Synthesis of fused pyran and arylbis(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)methane in ionic liquid

Promoted and mediated by an ionic liquid-[bmim][BF4], fused pyrans or arylbis（4-hydroxy-6-methyl-2-oxo-2H-pyran-3- yl）methanes were efficiently and selectively prepared from the reaction of aldehyde and 4-hydroxy-6-methyl-2-oxo-pyran with or without acetic anhydride. By using these novel procedures, pyrimidine nucleoside-fused pyran and arylbis（pyranon-3-yl）methane hybrids with potential biological activities were constructed.

Synthesis and Crystal Structure of N-tert-butyl-N′-(2,4-dichlorobenzoyl)-N- [1-(4-chlorophenyl)-1, 4-dihydro-6-methylpyridazine-4-oxo-3-carbonyl] hydrazine

The title compound N-tert-butyl-N(-(2,4-dichlorobenzoyl)-N-[1-(4-chlorophenyl)- 1,4-dihydro-6-methylpyridazine-4-oxo-3-carbonyl]hydrazine [(C23H_21N4O3Cl3)2·1.5H_2O, Mr = 1042.60] was prepared by the reaction of 1-(4-chlorophenyl)-1,4-dihydro-4-oxo-6- methylpyridazine-3-carboxylic acid with chloroformate ethyl ester, then with N′-tert-butyl-N- (2,4-dichlorobenzoyl) hydrazine in the present of triethylamine. The crystal structure has been determined by X-ray diffraction. The crystal belongs to Monoclinic, space group P21/c, with unit cell constants a =11.4948(9), b=12.7495(10), c=35.854(3) ?, β =92.964(2)°, Z=4, V=5247.6(7) ?3, Dc = 1.320 Mg/m3, F(000) = 2156 , μ (MoKa)= 0.385, R = 0.0661, wR = 0.1875, for 9151 observed reflections( I >2σ(I)). The structure is a dimer linked by intermolecular hydrogen bond which can be observed between N(1)- H...O(6), N(5)- H...O(3). The distances are 2.068 and 2.027? respectively.

Synthesis and Crystal Structure of Ethyl 3-(4-Chlorophenyl)-3,4-dihydro-6-methyl-4-oxo-2-(pyrrolidin-1-yl)furo[2,3-d]pyrimidine-5-carboxylate

The crystal structure of the title compound ethyl 3-（4-chlorophenyl）-3,4-dihydro-6- methyl-4-oxo-2-（pyrrolidin-1-yl）furo[2,3-d]pyrimidine-5-carboxylate （C20H20ClN3O4, Mr= 401.84） has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n with a = 20.6215（9）, b = 8.5311（4）, c = 21.6886（9） A^°, β = 91.607（1）°, V = 3814.0（3）A^°^3, Z = 8, Dc = 1.400 g/cm^3, F（000） = 1680, μ = 0.233 mm^-1, R = 0.0718 and wR = 0.1545 for 6717 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals two crystallographically independent molecules in the asymmetric unit.

The First Total Synthesis of 3-Oxo-11,12,13-trihydroxyeudesm-4-ene

The first total synthesis of 3-oxo-11,12,13-trihydroxyeudesm-4-ene,a highly oxygen- ated natural eudesmane, was described.

A Facile Synthesis of 3-Oxo-7αH-eudesma-4-ene-9β, 12-diol

A facile ndxture of the C-11 isomeric 3 - oxo-7αH-eudes ma-4-en- 9β, 1 2-diol has been achieved ffom oxycarvone. The C-11 configuration of natural product is established through comparison of IHNMR spectra between synthatic 1b, or the mixture of 1a and 1b, and natural diol.

A facile synthesis of novel unsymmetrical N-(4-oxo-2-phenyl-3(4H)-quinazolinoyl)-N-(aryl) acetamidines

A series of novel unsymmetrical N-（4-oxo-2-phenyl-3（4H）-quinazolinoyl）-N-（aryl） acetamidines was synthesized by reacting ethyl（1H）-N-（4-oxo-2-phenylquinazolin-3（4H）-y1）ethanimidoate（2） and suitable reactive aromatic amines.Structures＇ determination of the synthesized compounds was carried out using spectroscopic techniques including IR,~1H NMR,and mass spectrometry. Structural effects on reactivity were also studied.

Synthesis of Sodium 2-[4(S)-4-Amido-3-oxo-2-isoxazolidinyl]-5-oxo-2-tetrahydrofurancarboxylate and Its Antibacterial Activities

Lactivicin,a novel inhibitor of bacterial cell wall synthesis,was isolated from the culture fil-trates of microorganism YK-258 and YK-422.It exhibits biological activities similar to those ofthe β-lactam antibiotics,although it does not have a β-lactam ring in its molecule.Since the discovery of lactivicin,hundreds of its derivatives have been synthesized.

Synthesis and Crystal Structure of Ethyl 2-(6-(1,3-Dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl) Butanoate

The title compound ethyl 2-（6-（1,3-dioxo-4,5,6,7-tetrahydro-lH-isoindol-2（3H）- yl）-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4（3H）-yl） butanoate 3 was synthesized by the reaction of ethyl 2-（6-amino-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4（3H）-yl） butanoate with 4,5,6,7- tetraydrophthalic anhydride, and its structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P2 1/n with a = 9.3469（2）, b = 16.7715（5）, c = 13.7153（4） A, β= 104.9680（10）°, μ = 0.107 mm^-1, Mr = 430.42, V= 2077.08（10） ,A3, Z= 4, Dc = 1.376 g/cm3, F（000） = 904, T= 296（2） K, R = 0.0508 and wR = 0.1478.

Formation of (2E)-4-Hydroxy-2-nonenal and (2E)-4-Hydroxy-2-hexenal by Plant Enzymes: A Review Suggests a Role in the Physiology of Plants

It is demonstrated that (3Z)-nonenal (NON) and (3Z)-hexenal (HEX) are oxidized in a cascade by lipoxygenase (LOX) and hydroperoxide peroxygenase (HP peroxygenase) into (2E)-4-hydroxy-2- nonenal (HNE) and (2E)-4-hydroxy-2-hexenal (HHE), respectively. In turn, HNE inactivates LOX terminating the cascade. The hydroxy-alkenals produced serve to inhibit plant pathogens, which initiated the cascade. In addition to LOX, other unknown oxygenases may be involved in the cascade.

Cascade reaction of 3-formylchromones:Highly selective synthesis of 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes

A novel method for the preparation of highly functionalized 4-oxo-3-(1H-pyrrol-3-yl)-4H-chromenes(OPCMs)from 3-formylchromones andα-isocyanoacetates via an unprecedented three-component[1+1+3]cycloaddition reaction in one pot was developed.The three-component cascade reaction was enabled by refluxing a mixture of the substrates in 1,4-dioxane in the presence of Ag_(2)CO_(3) as a Lewis acid promoter.As a result,a series of functionalized pyrroles(OPCMs,3),was prepared regioselectively and in high yields(80%-88%)through the formation of three bonds.This protocol can be used in the synthesis of OPCMs rather than through conventional,multi-step reactions and is suitable for both combinatorial and parallel syntheses of pyrroles.

Synthesis and Fungicidal Activity of （E）-5-[1-（2-Oxo- 1 -oxaspiro[4,5]dec/non-3-en-3-yl）ethylidene]-2- aminoimidazolin-4-one Derivatives

The novel fungicidal agents, （E）-5-[1-（2-oxo-l-oxaspiro[4,5]dec/non-3-en-3-yl）ethylidene]-2-aminoimidazolin- 4-one derivatives, were designed and synthesized in moderate to excellent yields in four steps using a-hydroxyketone and diketene as raw materials and characterized by HR-ESI-MS, 1H NMR and X-ray diffraction. The preliminary bioassay showed that some of these compounds, such as 5e, 6a, 6e, and 7h exhibit 87.8%, 91.3%, 89.9% and 87.8% inhibition rates against Sclerotinia scleotiorum, 3b, 3c, 4c and 7h exhibit 96.4%, 92.5%, 90.3% and 76.9% inhibition rates against Phytophthora capsici at the concentration of 50 μg/mL, respectively. These compounds exhibited significant fungicidal activities against S. scleotiorum and P. capsici with EC50 values of 2.56 --11.60 μg/mL, and compounds 6e and 7h exhibited weak inhibition against the spore germination of S. scleoti- orum, while the spore germination ofP. capsici was strongly inhibited by compound 7h solution. Scanning electron microscopy （SEM） and transmission electron microscopy （TEM） observation indicated that compound 7h had a significant impact on the structure and function of the hyphal cell wall ofP. capsici mycelium.

A Green and Novel Method for the Synthesis of 4,4-Difluoro-3- oxo-2-（triphenylphosphoranylidene） 5-Lactones by Reformatsky Reaction

In the presence of In/CuCl, ethyl 4-bromo-4,4-difluoro-3-oxo-2-（triphenylphosphoranylidene）butanoate reacted with various aldehydes in aqueous medium at room temperature to give the a,a-difluorinated β-hydroxy carbonyl compounds. Furthermore, treating Reformatsky addition compounds with 1 equiv, of sodium hydroxide in the mixture of tetrahydrofuran and water afforded gem-difluoromethylenated 2-triphenylphosphoranylidene δ-lactones in excellent yields.

苏木心材中一个新黄酮类化合物

目的:从苏木Caesalpinia sappan中寻找新的活性成分。方法:用溶剂萃取及硅胶正相色谱进行活性成分的分离纯化,根据理化性质、光谱数据进行结构鉴定。结果:从苏木95%乙醇提取物中分离得到了9个化合物:3,8-dihydroxy-4,10-dimethoxy-7-oxo-[2]benzopyrano[4,3-b][1]benzopyran-7-(5H)-one(1),3-deoxysappanchal-cone(2),sappanchalcone(3),3-deoxysappanone B(4),鼠李素(rhamnetin,5),原苏木素C(protosappanin C,6),3,7-di-hydroxy-chroman-4-one(7),己二酸二甲酯(8),胡萝卜苷(daucosterin,9)。结论:化合物1为新化合物,化合物7,8为首次从该植物中分离得到。药理筛选结果表明,化合物3对多种癌细胞株具有一定的抑制活性。

Synthesis and Characterization of a Novel Galactosylated Cholesterol

A novel galactosylated cholesterol with mono-galactoside moiety, （5-cholesten-3-yl）-4-oxo-4-[2-（lactobionylamido）ethylamido]butanoate 6 was synthesized. Its chemical structure was characterized by IR, ESI-MS, ^13C NMR, ^1H NMR. Doxorubicin entrapped in the liposomes containing 10% mol/mol 6 was rapidly accumulated in liver and mainly uptake by parenchymal cells in mice.

Synthetic Studies of an Analogue of HIV-1 Protease Inhibitors of Didemnaketals:Construction of the C1-C8 Intermediate

A convenient and stereoselective approach to the synthesis of(3S. 4R. 6S)- 2-oxo-3, 4-dihydroxy-6-methyl-octanate derivative, a key intermediate for the synthesis of HIV-1 protease inhibitor of didemnaketals analogue, has been developed successfully from L-(-)-menthone.

Three pairs of alkaloid enantiomers from the root of Isatis indigotica

Three pairs of enantiomerically pure alkaloids with diverse structure features, named isatindigoticoic acid A and epiisatindigoticoic acid A [(—)-1 and(+)-1], phaitanthrin A and epiphaitanthrin A [(—)-2 and(+)-2], and isatindopyrromizol A and epiisatindopyrromizol A [(—)-3and(+)-3], respectively, were isolated from an aqueous extract of the roots of Isatis indigotica. Racemic and scalemic mixtures of these enantiomers were separated by HPLC on a chiral semi-preparative column.Their structures including absolute configurations were determined by extensive spectroscopic analysis in conjunction with the calculation of electronic circular dichroism(ECD) spectra. The enantiomer pairs possess parent structures of 2-oxo-1,2,3,4-tetrahydroquinoline-4-carboxylic acid, indolo[2,1-b]quinazolinone, and 3-thioxohexahydro-1H-pyrrolo[1,2-c]imidazol-1-one, respectively. Except for phaitanthrin A[(—)-2] which the configuration was previously undetermined, these compounds are new enantiomeric natural products.