This paper reports internal structures of a wide fault zone at Shenxigou,Dujiangyan,Sichuan province,China,and high-velocity frictional properties of the fault gouge collected near the coseismic slip zone during the 2...This paper reports internal structures of a wide fault zone at Shenxigou,Dujiangyan,Sichuan province,China,and high-velocity frictional properties of the fault gouge collected near the coseismic slip zone during the 2008 Wenchuan earthquake.Vertical offset and horizontal displacement at the trench site were 2.8 m(NW side up)and 4.8 m(right-lateral),respectively.The fault zone formed in Triassic sandstone,siltstone,and shale about 500 m away from the Yingxiu-Beichuan fault,a major fault in the Longmenshan fault system.A trench survey across the coseismic fault,and observations of outcrops and drill cores down to a depth of 57 m revealed that the fault zone consists of fault gouge and fault breccia of about0.5 and 250-300 m in widths,respectively,and that the fault strikes N62°E and dips 68° to NW.Quaternary conglomerates were recovered beneath the fault in the drilling,so that the fault moved at least 55 m along the coseismic slip zone,experiencing about 18 events of similar sizes.The fault core is composed of grayish gouge(GG) and blackish gouge(BG) with very complex slip-zone structures.BG contains low-crystalline graphite of about 30 %.High-velocity friction experiments were conducted at normal stresses of 0.6-2.1 MPa and slip rates of 0.1-2.1 m/s.Both GG and BG exhibit dramatic slip weakening at constant high slip rates that can be described as an exponential decay from peak friction coefficient lpto steadystate friction coefficient lssover a slip-weakening distance Dc.Deformation of GG and BG is characterized by overlapped slip-zone structures and development of sharp slickenside surfaces,respectively.Comparison of our data with those reported for other outcrops indicates that the high-velocity frictional properties of the Longmenshan fault zones are quite uniform and the high-velocity weakening must have promoted dynamic rupture propagation during the Wenchuan earthquake.展开更多
The title compound (E)-4-tert-butyl-N-(2,4-dichlorobenzylidene)-5-(1,2,4-triazol-1-yl)-thiazol-2-amine was synthesized by the reaction of 4-tert-butyl-5-(1,2,4-triazol-1-yl)-thiazol-2-amine with 2,4-dichlorobe...The title compound (E)-4-tert-butyl-N-(2,4-dichlorobenzylidene)-5-(1,2,4-triazol-1-yl)-thiazol-2-amine was synthesized by the reaction of 4-tert-butyl-5-(1,2,4-triazol-1-yl)-thiazol-2-amine with 2,4-dichlorobenzaldehyde, and its crystal structure was determined by singlecrystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.9748(4), b = 10.1803(5), c = 11.4603(6), α = 102.882(1), β = 100.253(1), γ = 104.457(1)°, V = 850.95(7)3, Z = 2, F(000) = 392, C16H15Cl2N5S, Mr = 380.29, Dc = 1.484 g/cm3, S = 1.095, μ = 0.512 mm-1, the final R = 0.0301 and wR = 0.0965 for 3334 observed reflections (I 〉 2σ(I)). The preliminary antitumor activity shows that for the title compound the IC50 of Hela is 0.175 μmol/mL and that of Bel7402 is 0.156 μmol/mL.展开更多
The title compound has been synthesized by the reaction of 4-tert-butyl-5-(1,2,4- triazol-1-yl)-2-aminothiazole with propionic anhydride, and its crystal structure was determined by single-crystal X-ray diffraction....The title compound has been synthesized by the reaction of 4-tert-butyl-5-(1,2,4- triazol-1-yl)-2-aminothiazole with propionic anhydride, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with α = 18.441(2), b = 8.3284(9), c = 19.257(2) A, Z = 8, V = 2957.5(5) A3, Mr = 279.37, Dc = 1.255 mg/m3, S = 1.033, μ =0.219 mm^-1, F(000) = 1184, the final R = 0.0349 and wR = 0.0876 for 2629 observed reflections (I 〉 2σ(I)). X-ray crystal structure presents the intermolecular N–H···N hydrogen bond, which plays an important role in stabilizing the crystal structure. The preliminary bioassay indicates that the title compound exhibits potent fungicidal activity against R. Solani (25 mg/L) with inhibition rate of 80.0%.展开更多
A new 1D coordination polymer [Co(bpp)3Cl2(H2O)2]n 1 (bpp = 1,3-bis(4-pyridyl)-propane) was synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction. The crystal bel...A new 1D coordination polymer [Co(bpp)3Cl2(H2O)2]n 1 (bpp = 1,3-bis(4-pyridyl)-propane) was synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system,space group Ibca with a = 16.569(9),b = 17.240(10),c = 27.087(16) ,V = 7738(8) 3,Z = 8,Dc = 1.306 g/cm3,Mr = 760.65,λ(MoKa) = 0.71073 ,μ = 0.623 mm1,F(000) = 3192,the final R = 0.0678 and wR = 0.2011. The Co(II) atom is coordinated in a slightly distorted octahedral CoN4Cl2 geometry by two Cl atoms in the axial positions,four N atoms from the two bridging bpp ligands and two pendant bpp ligands. The CoN4Cl2 octahedra are connected by the bridging bpp ligands to form a 1D neutral coordination polymer chain. The chains are linked by face-to-face π-π interactions between adjacent pendant bpp ligands to give rise to a 3D supramolecular architecture. The photoluminescent investigation indicates that the emission of 1 is attributed to ligand-centered emission. The variable-temperature magnetic susceptibility measurement shows weak antiferromagnetic behavior in the coπmplex.展开更多
A new ligand, 2-(2-hydroxyphenyl)-5,6-dichlorobenzimidazole, H2pbmCl2(1), and a novel MnIII complex, [MnIII(HpbmCl2)(pbmCl2)(DMF)2](2),(DMF = N,N-dimethylformamide), have been synthesized and characteriz...A new ligand, 2-(2-hydroxyphenyl)-5,6-dichlorobenzimidazole, H2pbmCl2(1), and a novel MnIII complex, [MnIII(HpbmCl2)(pbmCl2)(DMF)2](2),(DMF = N,N-dimethylformamide), have been synthesized and characterized. The crystal of compound 1(C13H8Cl2N2O, Mr = 279.12) belongs to the monoclinic system, space group P21 with a = 3.770(5), b = 25.20(3), c = 5.865(7) A, = 92.727(17)o, V = 556.6(12) A3, Z = 2, Dc = 1.665 g/cm^3, S = 1.137, μ= 0.568 mm^-1, F(000) = 284, the final R = 0.0876 and wR = 0.2334 for 1848 independent reflections. The molecule is planar due to the presence of a strong intramolecular hydrogen bond between O–H group of phenol and N atom of imidazole. H2pbmCl2(1) molecules are arranged into a one-dimensional linear chain through intermolecular hydrogen bonds(N–H…O and C–H…Cl). The crystal of complex 2(C32H27Cl4MnN6O4, Mr = 756.34) belongs to the monoclinic system, space group P21/c with a = 19.043(10), b = 10.808(5), c = 18.704(11)A, β= 115.540(6)°, V = 3473(3) A3, Z = 4, Dc = 1.446 g/cm^3, S = 1.3, μ = 0.733 mm-1, F(000) = 1544, the final R = 0.1219 and wR = 0.2681 for 7811 independent reflections. The Mn ion adopts a distorted octahedral geometry coordinated by two deprotonated H2pbmCl2 ligands and two DMF molecules. The [MnIII(HpbmCl2)(pbmCl2)(DMF)2] molecules are arranged into a three-dimensional structure through hydrogen bonds(N–H…N, C–H…N and C–H…Cl) and weak π···πinteractions. The activity measurements suggest that complex 2 is able to serve as a catalyst for H2O2 disproportionation reaction to form O2 in neutral water solution.展开更多
The title compound was synthesized by the reaction of 4-tert-butyl-5-(4-chlorobenzyl)-2-aminothiazole with 2,6-difluorobenzoic acid. The crystal structure of the title compound, C21H19ClF2N2OS, was determined by sin...The title compound was synthesized by the reaction of 4-tert-butyl-5-(4-chlorobenzyl)-2-aminothiazole with 2,6-difluorobenzoic acid. The crystal structure of the title compound, C21H19ClF2N2OS, was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group Pbca with a = 12.6479(13), b = 13.1204(13), c = 14.1341(15), Z = 4, V = 2011.5(4)3, Mr = 420.89, Dc = 1.390 g/cm3, S = 1.023, μ = 0.326 mm-1, F(000) = 872, the final R = 0.0365 and wR = 0.0880 for 6101 observed reflections(I 〉 2σ(I)), and R = 0.0507, wR = 0.0978 for 7779 independent reflections. X-ray crystal structure displays that the hydrogen bonding interactions observed link the molecules to form a dimeric unit. The preliminary biological test of the title compound shows good antitumor activity, with IC50 of 0.046 μmol/mL against the Hela cell line.展开更多
A novel Fe(II) coordination polymer [Fe(L)(trans-1,4-chdc)];~ has been hydrother- mally synthesized by using 1,4-cyclohexanedicarboxylic acid (1,4-H2chdc) and 2-(2-fluoro- phenyl)-lH-imidazo[4,5-f][1,10]phen...A novel Fe(II) coordination polymer [Fe(L)(trans-1,4-chdc)];~ has been hydrother- mally synthesized by using 1,4-cyclohexanedicarboxylic acid (1,4-H2chdc) and 2-(2-fluoro- phenyl)-lH-imidazo[4,5-f][1,10]phenanthroline (L). Crystallographic data: monoclinic, space group C2/c with a = 14.571(5), b = 32.389(6), c = 10.948(5)A, 18 = 115.186(5)°, V= 4676(3)A3, Z = 8, C27H21FFeN404, Mr = 540.33, De --- 1.535 g/cm3, F(000) = 2224, μ(MoKa) = 0.697 mmI, R = 0.0462 and wR = 0.1110. The two kinds of trans-l,4-chdc ligands link neighboring Fe(II) atoms to yield a two-dimensional layer structure. The π-π interactions between the L ligands of neighboring layers result in a three-dimensional supramolecular architecture. The IR and UV-vis spectra of the compound have been investigated in detail.展开更多
The title compound (E)-2-[(4-tert-butyl-5-(4-methoxybenzyl)thiazol-2-ylimino)methyl]phenol was synthesized by the reaction of 5-(4-methoxybenzyl)-4-tert- butylthiazol-2-amine with salicylaldehyde, and its crys...The title compound (E)-2-[(4-tert-butyl-5-(4-methoxybenzyl)thiazol-2-ylimino)methyl]phenol was synthesized by the reaction of 5-(4-methoxybenzyl)-4-tert- butylthiazol-2-amine with salicylaldehyde, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 5.9362(8), b = 11.5070(15), c = 29.460(4)A, β= 97.326(3)°, V = 1995.9(5) A^3, Z = 4, F(000) = 808, C22H24N2O2S, Mr= 380.49, De= 1.266 g/cm^3, S = 1.031,μ = 0.181 mm^-1, the final R = 0.0474 and wR = 0.1441 for 4327 observed reflections (I 〉 2σ(I)). Intramolecular O-H…N hydrogen bond is observed in the crystal. The preliminary bioassay showed that the title compound exhibits 95% inhibition rate against Rhizoctonia solani at the test concentration of 500 mg/L.展开更多
The title compounds, PhX2SnCHECHECO2Me (X = C1, 1a; Br, 1b; I, 1c), readily underwent transesterification into the corresponding analogues, PhX2SnCH2CH2CO2R when reacted with an alcohol ROH. The structural features ...The title compounds, PhX2SnCHECHECO2Me (X = C1, 1a; Br, 1b; I, 1c), readily underwent transesterification into the corresponding analogues, PhX2SnCH2CH2CO2R when reacted with an alcohol ROH. The structural features of these compounds were described, and the possible mechanism of the novel transesterification was suggested.展开更多
The title compound, C9H9N5OS, was synthesized by the reaction of 3-(1H)-1,2,4 -triazole hydrazine with 3-methyl-2-thiophenecarboxaldehyde in ethanol. The single crystal structure has been determined by X-ray diffrac...The title compound, C9H9N5OS, was synthesized by the reaction of 3-(1H)-1,2,4 -triazole hydrazine with 3-methyl-2-thiophenecarboxaldehyde in ethanol. The single crystal structure has been determined by X-ray diffraction analysis. The crystal belongs to monoclinic system, space group P2 1/n with a = 9.5550(10), b = 11.9847(12), c = 10.1074(11) A,β= 112.995(2)° V= 1065.47(19) A^3, Z = 4,μ = 0.290 mm^-1, Mr= 235.27, Dc = 1.467 g/cm^3 and F(000) = 488. The structure was solved by direct methods and refined to R = 0.0449. The crystal structure involves intermolecular hydrogen bonds of N-H…O and N-H…N as well as intramolecular hydrogen bond of N-H…N. Its biological activity has also been determined showing this type of compounds has certain antibacterial activity.展开更多
This paper extends Le van's work to the case of nonlinear problem and the complicated configuration. The wrinkling stress distribution and the pressure effects are also included in our analysis. Pseudo-beam method is...This paper extends Le van's work to the case of nonlinear problem and the complicated configuration. The wrinkling stress distribution and the pressure effects are also included in our analysis. Pseudo-beam method is presented based on the inflatable beam theory to model the inflatable structures as a set of inflatable beam elements with a prestressed state. In this method, the discretized nonlinear equations are given based upon the virtual work principle with a 3-node Timoshenko's beam model. Finite element simulation is performed by using a 3-node BEAM189 element incorporating ANSYS nonlinear program. The pressure effect is equivalent included in our method by modifying beam element cross-section parameters related to pressure. A benchmark example, the bending case of an inflatable cantilever beam, is performed to verify the accuracy of our proposed method. The comparisons reveal that the numerical results obtained with our method are close to open published analytical and membrane finite element results. The method is then used to evaluate the whole buckling and the loadcarrying characteristics of an inflatable support frame subjected to a compression force. The wrinkling stress and region characteristics are also shown in the end. This method gives better convergence characteristics, and requires much less computation time. It is very effective to deal with the whole load-carrying ability analytical problems for large scale inflatable structures with complex configuration.展开更多
Two novel fluorine-containing cyclophanes 1 and 2 incorporating a 1,4-bismethylfluorophenylene subunits have been synthesized via the template-directed clipping methodology and their structure was characterized by ~1H...Two novel fluorine-containing cyclophanes 1 and 2 incorporating a 1,4-bismethylfluorophenylene subunits have been synthesized via the template-directed clipping methodology and their structure was characterized by ~1H NMR,^(13)C NMR, MALDI-TOF-MS and elemental analysis.X-ray diffraction analysis of the solid state molecular structure showed that the complex units are linked by non-classical C-H…F hydrogen bonding.展开更多
The title compound 2(C22H28N+O3)·H2O·2Cl-was synthesized by the reaction of 2-bromo-1-[4-(benzyloxy)phenyl]-1-pentone with 2,2'-azanediyldiethanol. The crystal determined by X-ray diffraction analysis ...The title compound 2(C22H28N+O3)·H2O·2Cl-was synthesized by the reaction of 2-bromo-1-[4-(benzyloxy)phenyl]-1-pentone with 2,2'-azanediyldiethanol. The crystal determined by X-ray diffraction analysis belongs to the monoclinic system, space group Pc with a = 18.312(3), b = 14.838(3), c = 7.6227(14) , β = 97.981(4)°, Z = 2, Mr = 797.82, V = 2051.1(6) 3, Dc = 1.292 g/cm3, S = 0.956, μ = 0.21 mm-1, F(000) = 852, the final R = 0.0625 and wR = 0.1428 for 5683 observed reflections (Ⅰ 〉 2σ(Ⅰ)). Flack parameter is 0.10(9). The title compound is composed by four non-coplanar ring systems, two benzenes and two morpholines. One morpholine ring (C(3)-C(4)-N(1)-C(1)-C(2)-O(1)) forms a chair conformation, while the other (C(4)-C(3)-O(2)-C(6)-C(5)-N(1)) assumes a boat conformation. X-ray crystal structure displays extensive N-H…Cl and O-H…Cl intermolecular hydrogen bonds. The preliminary antidepressant activity test indicates that the inhibition ratio of SERT (5-HT Transporter) was 35.9% at the dosage of 10.0 mg/L.展开更多
The title compound, N-(2-(1H-indol-3-yl)ethyl)-2-nitroaniline(C16H15N3O2, Mr = 281.31), has been synthesized by the multicomponent reaction of milder Ullmann, and its structure was characterized by 1H NMR, 13 C NMR, I...The title compound, N-(2-(1H-indol-3-yl)ethyl)-2-nitroaniline(C16H15N3O2, Mr = 281.31), has been synthesized by the multicomponent reaction of milder Ullmann, and its structure was characterized by 1H NMR, 13 C NMR, IR, H RMS(ESI) and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group I2/c with a = 15.0212(10), b = 9.4911(6), c = 20.3075(13) A, β = 100.776(7)o, V = 2844.1(3)A3, Z = 8, Dc = 1.314 g/cm3, F(000) = 1184.0, μ = 0.089 mm-1, the final R = 0.0574 and w R = 0.1688 for 1701 observed reflections(I 】 2σ(I)). X-ray analysis indicates three major N(2)–H(2)···O(2), C(13)–H(13)···O(2), N(2)–H(2)···N(3) hydrogen bonds and π-π stacking interactions in the crystal structure. The preliminary biological test shows that the title compound has a good antitumor activity against A549 in vitro with the IC50 value of 35 μmol/L.展开更多
The title compound has been synthesized by the reaction of 3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one oxime with 2-chlorobenzyl chloride, and then treated with 65~68% HNO3. Its crystal structure was determin...The title compound has been synthesized by the reaction of 3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one oxime with 2-chlorobenzyl chloride, and then treated with 65~68% HNO3. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 14.5481(8), b = 9.3351(5), c = 13.1911(7) , β = 98.9450(10)°, Z = 4, V = 1769.67(17) 3, Mr = 369.81, Dc = 1.388 g/cm3, S = 1.06, μ = 0.247 mm-1, F(000) = 776, the final R = 0.0352 and wR = 0.0960 for 3069 observed reflections (I 2σ(I)). X-ray crystal structure presents the intramolecular N–H…O hydrogen bond. The packing is nearly parallel without π-π stacking interactions between two adjacent phenyl rings and stabilized by Van der Waals force. The preliminary bioassay shows that the title compound possesses fungicidal activity against Gibberella zeae at the dosage of 25 mg/L.展开更多
Fifteen novel 2-(3-oxobenzo[d]isothiazol-2(3H)-yl)ethyl benzoates were synthesi- zed by the condensation of 2-(2-hydroxyethyl)benzo[d]isothiazol-3(2H)-one with substituted benzoic acids in dichloromethane. All...Fifteen novel 2-(3-oxobenzo[d]isothiazol-2(3H)-yl)ethyl benzoates were synthesi- zed by the condensation of 2-(2-hydroxyethyl)benzo[d]isothiazol-3(2H)-one with substituted benzoic acids in dichloromethane. All the compounds were characterized by elemental analysis, IR, ESI-MS and 1H NMR. The crystal structures for 2-(2-hydroxyethyl)benzo[d]isothiazol-3(2H)-one (2) and 2-(3-oxobenzo[d]isothiazol-2(3H)-yl)ethyl 2-methoxybenzoate (30) have been determined by X-ray crystal structure analysis. Compound 2 (C9H9NO2S) crystallizes in the monoclinic system, space group Pn with a = 10.552(3), b = 7.849(2), c = 10.765(4) A, β = 103.128(4)°, V= 868.3(5) A3, Mr = 195.24, Dc = 1.493 Mg.m-3, μ = 0.33 mm-1, F(000) = 408, Z = 4, R= 0.0314 and wR= 0.0628. Compound 30 (C17H15NO4S) crystallizes in the triclinic system, space group P1 with a = 8.028(2), b = 9.300(2), c = 10.430(3)A, V= 752.1(3)A3, Mr = 329.36, D,= 1.454 Mg.m-3, p = 0.24 mm-1, F(000) = 344, Z = 2, R = 0.0377 and wR = 0.0904. The preliminary biological test indicated that the title compounds show better growth inhibitory activity against the gram-positive bacteria than the gram-negative bacteria.展开更多
The title compound has been synthesized by the reaction of 1-bromo-3,3-dime- thyl- 1 - (1 H- 1,2,4-triazol- 1 -yl)butan-2-one with 1 -(2-fluorophenyl)thiourea, and its crystal struc- ture was determined by single-...The title compound has been synthesized by the reaction of 1-bromo-3,3-dime- thyl- 1 - (1 H- 1,2,4-triazol- 1 -yl)butan-2-one with 1 -(2-fluorophenyl)thiourea, and its crystal struc- ture was determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with a = 15.2568(6), b = 12.1533(5), c = 16.7307(7) A, Z = 8, V = 3102.2(2) A3, Mr = 317.39, Dc = 1.359 g/cm3, S = 1.05, μ = 0.223 mm-1, F(000) = 1328, the final R = 0.034 and wR = 0.097 for 2590 observed reflections (I 〉 2σ(I)). X-ray crystal structure presents the intramolecular N-H…N hydrogen bond, which plays an important role in stabilizing the crystal structure. In addition, the preliminary biological test on the title compound shows good antitumor activity, with IC50 of 0.122 μmol/mL against the Hela cell line.展开更多
A novel Zn(Ⅱ) complex, [ZnL2(H2O)4]·H2O(1, HL = 2-(nicotinoyloxy)acetic acid), was synthesized using Zn(OAc)2·2H2O and 2-(nicotinoyloxy)acetic acid as raw materials. Its structure has been eluci...A novel Zn(Ⅱ) complex, [ZnL2(H2O)4]·H2O(1, HL = 2-(nicotinoyloxy)acetic acid), was synthesized using Zn(OAc)2·2H2O and 2-(nicotinoyloxy)acetic acid as raw materials. Its structure has been elucidated by elemental analysis, IR and single-crystal X-ray diffraction. The structural analysis revealed that complex 1 crystallizes in triclinic, space group P1 and the Zn(Ⅱ) atom is six-coordinated with two N atoms from two different 2-(nicotinoyloxy)acetate anion ligands and four O atoms from coordinated water molecules. Complex 1 forms a 3D network structure by O–H···O hydrogen bonds. The antitumor activities of 2-(nicotinoyloxy)acetic acid ligand and its Zn(Ⅱ) complex were evaluated against human lung adenocarcinoma A549 cells, human hepatoma SMMC-7721 cells and human colon carcinoma Wi Dr cells.展开更多
The title compound 1-(3-amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one(3) was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one(1) and ~1H-[1,2,4]triazol-3-ylamine(2) with eq...The title compound 1-(3-amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one(3) was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one(1) and ~1H-[1,2,4]triazol-3-ylamine(2) with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227(8), b = 27.924(4), c = 6.2282(7) ?, β = 101.892(11)°, V = 973.9(2) ?~3, Z = 4, T = 180.00(10) K, μ(MoKα) = 0.087 mm^(-1), Dc = 1.243 g/cm^3, 3832 reflections measured(3.648≤θ≤26.022°), 1916 unique reflections(Rint = 0.0359, Rsigma = 0.0572) used in all calculations. The final R = 0.0557(I 〉 2σ(I)) and w R = 0.1276(all data). Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L(50 ppm) in soybeen(He Feng-50). Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.展开更多
On the basis of the interesting structures and biological activities exhibited by several heterocyclic systems possessing the pyridone nucleus such as mappcine and camptothecin, we have planed to design the synthesis,...On the basis of the interesting structures and biological activities exhibited by several heterocyclic systems possessing the pyridone nucleus such as mappcine and camptothecin, we have planed to design the synthesis, crystal studies and antibacterial activity of the new 1-((2- chloroquinolin-3yl)-methyl)-pyridine-2(1H)-one building block. An X-ray analysis has provided valuable insight into the effect of steric factors on the three-dimensional shape of this compound which serves as a useful advanced intermediate in the synthesis of these biologically active molecules. A multistep synthesis of camptothecin (5) has been designed by retrosynthetic analysis as part of an ongoing program on lead anticancer drug.展开更多
基金supported by State Key Laboratory of Earthquake Dynamics (project No.LED2010A03)Wenchuan Earthquake Fault Scientific Drilling Project (WFSD-09)
文摘This paper reports internal structures of a wide fault zone at Shenxigou,Dujiangyan,Sichuan province,China,and high-velocity frictional properties of the fault gouge collected near the coseismic slip zone during the 2008 Wenchuan earthquake.Vertical offset and horizontal displacement at the trench site were 2.8 m(NW side up)and 4.8 m(right-lateral),respectively.The fault zone formed in Triassic sandstone,siltstone,and shale about 500 m away from the Yingxiu-Beichuan fault,a major fault in the Longmenshan fault system.A trench survey across the coseismic fault,and observations of outcrops and drill cores down to a depth of 57 m revealed that the fault zone consists of fault gouge and fault breccia of about0.5 and 250-300 m in widths,respectively,and that the fault strikes N62°E and dips 68° to NW.Quaternary conglomerates were recovered beneath the fault in the drilling,so that the fault moved at least 55 m along the coseismic slip zone,experiencing about 18 events of similar sizes.The fault core is composed of grayish gouge(GG) and blackish gouge(BG) with very complex slip-zone structures.BG contains low-crystalline graphite of about 30 %.High-velocity friction experiments were conducted at normal stresses of 0.6-2.1 MPa and slip rates of 0.1-2.1 m/s.Both GG and BG exhibit dramatic slip weakening at constant high slip rates that can be described as an exponential decay from peak friction coefficient lpto steadystate friction coefficient lssover a slip-weakening distance Dc.Deformation of GG and BG is characterized by overlapped slip-zone structures and development of sharp slickenside surfaces,respectively.Comparison of our data with those reported for other outcrops indicates that the high-velocity frictional properties of the Longmenshan fault zones are quite uniform and the high-velocity weakening must have promoted dynamic rupture propagation during the Wenchuan earthquake.
基金Supported by the Natural Science Foundation of Hunan Province (No. 07JJ302)
文摘The title compound (E)-4-tert-butyl-N-(2,4-dichlorobenzylidene)-5-(1,2,4-triazol-1-yl)-thiazol-2-amine was synthesized by the reaction of 4-tert-butyl-5-(1,2,4-triazol-1-yl)-thiazol-2-amine with 2,4-dichlorobenzaldehyde, and its crystal structure was determined by singlecrystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.9748(4), b = 10.1803(5), c = 11.4603(6), α = 102.882(1), β = 100.253(1), γ = 104.457(1)°, V = 850.95(7)3, Z = 2, F(000) = 392, C16H15Cl2N5S, Mr = 380.29, Dc = 1.484 g/cm3, S = 1.095, μ = 0.512 mm-1, the final R = 0.0301 and wR = 0.0965 for 3334 observed reflections (I 〉 2σ(I)). The preliminary antitumor activity shows that for the title compound the IC50 of Hela is 0.175 μmol/mL and that of Bel7402 is 0.156 μmol/mL.
基金supported by the Natural Science Foundation of Hunan Province(No.12jj3012)
文摘The title compound has been synthesized by the reaction of 4-tert-butyl-5-(1,2,4- triazol-1-yl)-2-aminothiazole with propionic anhydride, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with α = 18.441(2), b = 8.3284(9), c = 19.257(2) A, Z = 8, V = 2957.5(5) A3, Mr = 279.37, Dc = 1.255 mg/m3, S = 1.033, μ =0.219 mm^-1, F(000) = 1184, the final R = 0.0349 and wR = 0.0876 for 2629 observed reflections (I 〉 2σ(I)). X-ray crystal structure presents the intermolecular N–H···N hydrogen bond, which plays an important role in stabilizing the crystal structure. The preliminary bioassay indicates that the title compound exhibits potent fungicidal activity against R. Solani (25 mg/L) with inhibition rate of 80.0%.
基金supported by the National High Technology Research and Development Program of China (863 Program) (No. SQ2008AA03Z2470974)the National Natural Science Foundation of China (Nos. 50572030 and 50372022)the Young Talent Program of Fujian Province (No. 2007F3060)
文摘A new 1D coordination polymer [Co(bpp)3Cl2(H2O)2]n 1 (bpp = 1,3-bis(4-pyridyl)-propane) was synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system,space group Ibca with a = 16.569(9),b = 17.240(10),c = 27.087(16) ,V = 7738(8) 3,Z = 8,Dc = 1.306 g/cm3,Mr = 760.65,λ(MoKa) = 0.71073 ,μ = 0.623 mm1,F(000) = 3192,the final R = 0.0678 and wR = 0.2011. The Co(II) atom is coordinated in a slightly distorted octahedral CoN4Cl2 geometry by two Cl atoms in the axial positions,four N atoms from the two bridging bpp ligands and two pendant bpp ligands. The CoN4Cl2 octahedra are connected by the bridging bpp ligands to form a 1D neutral coordination polymer chain. The chains are linked by face-to-face π-π interactions between adjacent pendant bpp ligands to give rise to a 3D supramolecular architecture. The photoluminescent investigation indicates that the emission of 1 is attributed to ligand-centered emission. The variable-temperature magnetic susceptibility measurement shows weak antiferromagnetic behavior in the coπmplex.
基金supported by the National Natural Science Foundation of China(No.20973186 and 31070216)
文摘A new ligand, 2-(2-hydroxyphenyl)-5,6-dichlorobenzimidazole, H2pbmCl2(1), and a novel MnIII complex, [MnIII(HpbmCl2)(pbmCl2)(DMF)2](2),(DMF = N,N-dimethylformamide), have been synthesized and characterized. The crystal of compound 1(C13H8Cl2N2O, Mr = 279.12) belongs to the monoclinic system, space group P21 with a = 3.770(5), b = 25.20(3), c = 5.865(7) A, = 92.727(17)o, V = 556.6(12) A3, Z = 2, Dc = 1.665 g/cm^3, S = 1.137, μ= 0.568 mm^-1, F(000) = 284, the final R = 0.0876 and wR = 0.2334 for 1848 independent reflections. The molecule is planar due to the presence of a strong intramolecular hydrogen bond between O–H group of phenol and N atom of imidazole. H2pbmCl2(1) molecules are arranged into a one-dimensional linear chain through intermolecular hydrogen bonds(N–H…O and C–H…Cl). The crystal of complex 2(C32H27Cl4MnN6O4, Mr = 756.34) belongs to the monoclinic system, space group P21/c with a = 19.043(10), b = 10.808(5), c = 18.704(11)A, β= 115.540(6)°, V = 3473(3) A3, Z = 4, Dc = 1.446 g/cm^3, S = 1.3, μ = 0.733 mm-1, F(000) = 1544, the final R = 0.1219 and wR = 0.2681 for 7811 independent reflections. The Mn ion adopts a distorted octahedral geometry coordinated by two deprotonated H2pbmCl2 ligands and two DMF molecules. The [MnIII(HpbmCl2)(pbmCl2)(DMF)2] molecules are arranged into a three-dimensional structure through hydrogen bonds(N–H…N, C–H…N and C–H…Cl) and weak π···πinteractions. The activity measurements suggest that complex 2 is able to serve as a catalyst for H2O2 disproportionation reaction to form O2 in neutral water solution.
基金Project supported by the National Technology R&D Program(No.2011 BAE06B01)
文摘The title compound was synthesized by the reaction of 4-tert-butyl-5-(4-chlorobenzyl)-2-aminothiazole with 2,6-difluorobenzoic acid. The crystal structure of the title compound, C21H19ClF2N2OS, was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group Pbca with a = 12.6479(13), b = 13.1204(13), c = 14.1341(15), Z = 4, V = 2011.5(4)3, Mr = 420.89, Dc = 1.390 g/cm3, S = 1.023, μ = 0.326 mm-1, F(000) = 872, the final R = 0.0365 and wR = 0.0880 for 6101 observed reflections(I 〉 2σ(I)), and R = 0.0507, wR = 0.0978 for 7779 independent reflections. X-ray crystal structure displays that the hydrogen bonding interactions observed link the molecules to form a dimeric unit. The preliminary biological test of the title compound shows good antitumor activity, with IC50 of 0.046 μmol/mL against the Hela cell line.
基金Supported by the Institute Foundation of Siping City(No.2009011)
文摘A novel Fe(II) coordination polymer [Fe(L)(trans-1,4-chdc)];~ has been hydrother- mally synthesized by using 1,4-cyclohexanedicarboxylic acid (1,4-H2chdc) and 2-(2-fluoro- phenyl)-lH-imidazo[4,5-f][1,10]phenanthroline (L). Crystallographic data: monoclinic, space group C2/c with a = 14.571(5), b = 32.389(6), c = 10.948(5)A, 18 = 115.186(5)°, V= 4676(3)A3, Z = 8, C27H21FFeN404, Mr = 540.33, De --- 1.535 g/cm3, F(000) = 2224, μ(MoKa) = 0.697 mmI, R = 0.0462 and wR = 0.1110. The two kinds of trans-l,4-chdc ligands link neighboring Fe(II) atoms to yield a two-dimensional layer structure. The π-π interactions between the L ligands of neighboring layers result in a three-dimensional supramolecular architecture. The IR and UV-vis spectra of the compound have been investigated in detail.
基金the National Project of Scientific and Technical Supporting Programs and Ministry of Science & Technology of China (No.2006BAE01A01-4)
文摘The title compound (E)-2-[(4-tert-butyl-5-(4-methoxybenzyl)thiazol-2-ylimino)methyl]phenol was synthesized by the reaction of 5-(4-methoxybenzyl)-4-tert- butylthiazol-2-amine with salicylaldehyde, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 5.9362(8), b = 11.5070(15), c = 29.460(4)A, β= 97.326(3)°, V = 1995.9(5) A^3, Z = 4, F(000) = 808, C22H24N2O2S, Mr= 380.49, De= 1.266 g/cm^3, S = 1.031,μ = 0.181 mm^-1, the final R = 0.0474 and wR = 0.1441 for 4327 observed reflections (I 〉 2σ(I)). Intramolecular O-H…N hydrogen bond is observed in the crystal. The preliminary bioassay showed that the title compound exhibits 95% inhibition rate against Rhizoctonia solani at the test concentration of 500 mg/L.
基金This work was supported by the National Natural Science Foundation of China(No.20173050)Natural Science Foundation of Shandong Province(No.Z2002F01).
文摘The title compounds, PhX2SnCHECHECO2Me (X = C1, 1a; Br, 1b; I, 1c), readily underwent transesterification into the corresponding analogues, PhX2SnCH2CH2CO2R when reacted with an alcohol ROH. The structural features of these compounds were described, and the possible mechanism of the novel transesterification was suggested.
基金This work was supported by the Natural Science Foundation of Zhejiang Province (No. M203115) and Scientific Research Fund of Zhejiang Provincial Education Department(NO.20050057)
文摘The title compound, C9H9N5OS, was synthesized by the reaction of 3-(1H)-1,2,4 -triazole hydrazine with 3-methyl-2-thiophenecarboxaldehyde in ethanol. The single crystal structure has been determined by X-ray diffraction analysis. The crystal belongs to monoclinic system, space group P2 1/n with a = 9.5550(10), b = 11.9847(12), c = 10.1074(11) A,β= 112.995(2)° V= 1065.47(19) A^3, Z = 4,μ = 0.290 mm^-1, Mr= 235.27, Dc = 1.467 g/cm^3 and F(000) = 488. The structure was solved by direct methods and refined to R = 0.0449. The crystal structure involves intermolecular hydrogen bonds of N-H…O and N-H…N as well as intramolecular hydrogen bond of N-H…N. Its biological activity has also been determined showing this type of compounds has certain antibacterial activity.
基金supported by the Specialized Fund for the Doctoral Program of Higher Education of China (200802131046)China Postdoctoral Science Foundation Funded Major Project (200801290)+1 种基金Development Program of Outstanding Young Teachers in Harbin Institute of Technology (HITQNJS.2008.004)Specialized Fund for Innovation Talents of Science and Technology in Harbin (2008RFQXG057).
文摘This paper extends Le van's work to the case of nonlinear problem and the complicated configuration. The wrinkling stress distribution and the pressure effects are also included in our analysis. Pseudo-beam method is presented based on the inflatable beam theory to model the inflatable structures as a set of inflatable beam elements with a prestressed state. In this method, the discretized nonlinear equations are given based upon the virtual work principle with a 3-node Timoshenko's beam model. Finite element simulation is performed by using a 3-node BEAM189 element incorporating ANSYS nonlinear program. The pressure effect is equivalent included in our method by modifying beam element cross-section parameters related to pressure. A benchmark example, the bending case of an inflatable cantilever beam, is performed to verify the accuracy of our proposed method. The comparisons reveal that the numerical results obtained with our method are close to open published analytical and membrane finite element results. The method is then used to evaluate the whole buckling and the loadcarrying characteristics of an inflatable support frame subjected to a compression force. The wrinkling stress and region characteristics are also shown in the end. This method gives better convergence characteristics, and requires much less computation time. It is very effective to deal with the whole load-carrying ability analytical problems for large scale inflatable structures with complex configuration.
基金support from the National Natural Science Foundation of China(No.20872051)
文摘Two novel fluorine-containing cyclophanes 1 and 2 incorporating a 1,4-bismethylfluorophenylene subunits have been synthesized via the template-directed clipping methodology and their structure was characterized by ~1H NMR,^(13)C NMR, MALDI-TOF-MS and elemental analysis.X-ray diffraction analysis of the solid state molecular structure showed that the complex units are linked by non-classical C-H…F hydrogen bonding.
基金Project supported by the National Technology R&D Program (No. 2011 BAE06B01)
文摘The title compound 2(C22H28N+O3)·H2O·2Cl-was synthesized by the reaction of 2-bromo-1-[4-(benzyloxy)phenyl]-1-pentone with 2,2'-azanediyldiethanol. The crystal determined by X-ray diffraction analysis belongs to the monoclinic system, space group Pc with a = 18.312(3), b = 14.838(3), c = 7.6227(14) , β = 97.981(4)°, Z = 2, Mr = 797.82, V = 2051.1(6) 3, Dc = 1.292 g/cm3, S = 0.956, μ = 0.21 mm-1, F(000) = 852, the final R = 0.0625 and wR = 0.1428 for 5683 observed reflections (Ⅰ 〉 2σ(Ⅰ)). Flack parameter is 0.10(9). The title compound is composed by four non-coplanar ring systems, two benzenes and two morpholines. One morpholine ring (C(3)-C(4)-N(1)-C(1)-C(2)-O(1)) forms a chair conformation, while the other (C(4)-C(3)-O(2)-C(6)-C(5)-N(1)) assumes a boat conformation. X-ray crystal structure displays extensive N-H…Cl and O-H…Cl intermolecular hydrogen bonds. The preliminary antidepressant activity test indicates that the inhibition ratio of SERT (5-HT Transporter) was 35.9% at the dosage of 10.0 mg/L.
基金supported by the Fundamental Research Funds for the Central Universities(lzujbky-2010-137)Lanzhou Science and Technology Bureau Program Funds(2012-2-90)
文摘The title compound, N-(2-(1H-indol-3-yl)ethyl)-2-nitroaniline(C16H15N3O2, Mr = 281.31), has been synthesized by the multicomponent reaction of milder Ullmann, and its structure was characterized by 1H NMR, 13 C NMR, IR, H RMS(ESI) and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group I2/c with a = 15.0212(10), b = 9.4911(6), c = 20.3075(13) A, β = 100.776(7)o, V = 2844.1(3)A3, Z = 8, Dc = 1.314 g/cm3, F(000) = 1184.0, μ = 0.089 mm-1, the final R = 0.0574 and w R = 0.1688 for 1701 observed reflections(I 】 2σ(I)). X-ray analysis indicates three major N(2)–H(2)···O(2), C(13)–H(13)···O(2), N(2)–H(2)···N(3) hydrogen bonds and π-π stacking interactions in the crystal structure. The preliminary biological test shows that the title compound has a good antitumor activity against A549 in vitro with the IC50 value of 35 μmol/L.
基金Supported by the Central University Basic Scientific Research Fund of Hunan University (2009)the Key Scientific and Technological Project of Changsha, Hunan Province (No. 0901077-31)
文摘The title compound has been synthesized by the reaction of 3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one oxime with 2-chlorobenzyl chloride, and then treated with 65~68% HNO3. Its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/c with a = 14.5481(8), b = 9.3351(5), c = 13.1911(7) , β = 98.9450(10)°, Z = 4, V = 1769.67(17) 3, Mr = 369.81, Dc = 1.388 g/cm3, S = 1.06, μ = 0.247 mm-1, F(000) = 776, the final R = 0.0352 and wR = 0.0960 for 3069 observed reflections (I 2σ(I)). X-ray crystal structure presents the intramolecular N–H…O hydrogen bond. The packing is nearly parallel without π-π stacking interactions between two adjacent phenyl rings and stabilized by Van der Waals force. The preliminary bioassay shows that the title compound possesses fungicidal activity against Gibberella zeae at the dosage of 25 mg/L.
基金Supported by the National Natural Science Foundation of China (No. 20962007)
文摘Fifteen novel 2-(3-oxobenzo[d]isothiazol-2(3H)-yl)ethyl benzoates were synthesi- zed by the condensation of 2-(2-hydroxyethyl)benzo[d]isothiazol-3(2H)-one with substituted benzoic acids in dichloromethane. All the compounds were characterized by elemental analysis, IR, ESI-MS and 1H NMR. The crystal structures for 2-(2-hydroxyethyl)benzo[d]isothiazol-3(2H)-one (2) and 2-(3-oxobenzo[d]isothiazol-2(3H)-yl)ethyl 2-methoxybenzoate (30) have been determined by X-ray crystal structure analysis. Compound 2 (C9H9NO2S) crystallizes in the monoclinic system, space group Pn with a = 10.552(3), b = 7.849(2), c = 10.765(4) A, β = 103.128(4)°, V= 868.3(5) A3, Mr = 195.24, Dc = 1.493 Mg.m-3, μ = 0.33 mm-1, F(000) = 408, Z = 4, R= 0.0314 and wR= 0.0628. Compound 30 (C17H15NO4S) crystallizes in the triclinic system, space group P1 with a = 8.028(2), b = 9.300(2), c = 10.430(3)A, V= 752.1(3)A3, Mr = 329.36, D,= 1.454 Mg.m-3, p = 0.24 mm-1, F(000) = 344, Z = 2, R = 0.0377 and wR = 0.0904. The preliminary biological test indicated that the title compounds show better growth inhibitory activity against the gram-positive bacteria than the gram-negative bacteria.
基金Project supported by the National Technology R&D Program (No. 2011 BAE06B01)
文摘The title compound has been synthesized by the reaction of 1-bromo-3,3-dime- thyl- 1 - (1 H- 1,2,4-triazol- 1 -yl)butan-2-one with 1 -(2-fluorophenyl)thiourea, and its crystal struc- ture was determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with a = 15.2568(6), b = 12.1533(5), c = 16.7307(7) A, Z = 8, V = 3102.2(2) A3, Mr = 317.39, Dc = 1.359 g/cm3, S = 1.05, μ = 0.223 mm-1, F(000) = 1328, the final R = 0.034 and wR = 0.097 for 2590 observed reflections (I 〉 2σ(I)). X-ray crystal structure presents the intramolecular N-H…N hydrogen bond, which plays an important role in stabilizing the crystal structure. In addition, the preliminary biological test on the title compound shows good antitumor activity, with IC50 of 0.122 μmol/mL against the Hela cell line.
基金supported by the National Natural Science Foundation of China(No.21171132)the Project of Shandong Province Higher Educational Science and Technology Program(J14LC01)Science Foundation of Weifang
文摘A novel Zn(Ⅱ) complex, [ZnL2(H2O)4]·H2O(1, HL = 2-(nicotinoyloxy)acetic acid), was synthesized using Zn(OAc)2·2H2O and 2-(nicotinoyloxy)acetic acid as raw materials. Its structure has been elucidated by elemental analysis, IR and single-crystal X-ray diffraction. The structural analysis revealed that complex 1 crystallizes in triclinic, space group P1 and the Zn(Ⅱ) atom is six-coordinated with two N atoms from two different 2-(nicotinoyloxy)acetate anion ligands and four O atoms from coordinated water molecules. Complex 1 forms a 3D network structure by O–H···O hydrogen bonds. The antitumor activities of 2-(nicotinoyloxy)acetic acid ligand and its Zn(Ⅱ) complex were evaluated against human lung adenocarcinoma A549 cells, human hepatoma SMMC-7721 cells and human colon carcinoma Wi Dr cells.
基金supported by the National Natural Science Foundation of China(No.2012BAD20B04)
文摘The title compound 1-(3-amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one(3) was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one(1) and ~1H-[1,2,4]triazol-3-ylamine(2) with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227(8), b = 27.924(4), c = 6.2282(7) ?, β = 101.892(11)°, V = 973.9(2) ?~3, Z = 4, T = 180.00(10) K, μ(MoKα) = 0.087 mm^(-1), Dc = 1.243 g/cm^3, 3832 reflections measured(3.648≤θ≤26.022°), 1916 unique reflections(Rint = 0.0359, Rsigma = 0.0572) used in all calculations. The final R = 0.0557(I 〉 2σ(I)) and w R = 0.1276(all data). Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L(50 ppm) in soybeen(He Feng-50). Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.
基金supported by the Department of Science & Technology Government of India (No. SR/FTP/CS-99/2006)
文摘On the basis of the interesting structures and biological activities exhibited by several heterocyclic systems possessing the pyridone nucleus such as mappcine and camptothecin, we have planed to design the synthesis, crystal studies and antibacterial activity of the new 1-((2- chloroquinolin-3yl)-methyl)-pyridine-2(1H)-one building block. An X-ray analysis has provided valuable insight into the effect of steric factors on the three-dimensional shape of this compound which serves as a useful advanced intermediate in the synthesis of these biologically active molecules. A multistep synthesis of camptothecin (5) has been designed by retrosynthetic analysis as part of an ongoing program on lead anticancer drug.