Photocatalytic hydrogen-evolution dimerization of styrenes to synthesize 1,2-dihydro-1-arylnaphthalene derivatives using Acr^+-Mes and cobaloxime catalysts

We report a hydrogen-evolution dimerization of styrenes via the synergistic merger of Acr＋-Mes photocatalyst and cobaloxime proton reduction catalysts. By utilizing this dual catalyst system, 1,2-dihydro-1-arylnaphthalene derivatives can be directly constructed from commercially available styrenes. Our reaction proceeds smoothly under mild conditions without the need for oxidants or hydrogen atom transfer reagents, and the sole byproduct is hydrogen gas. Mechanistic investigation suggests that the reaction is initiated by photoinduced electron transfer under visible-light irradiation.

Selenium-catalyzed oxidative carbonylation of 2-aminobenzyl alcohol to give 1,4-dihydro-2H-3,1-benzoxazin-2-one

An efficient,economical,and phosgene-free approach was developed for the preparation of l,4-dihydro-2H-3,l-benzoxazin-2-one from 2-aminobenzyl alcohol.In terms of its key features,this reaction uses the cheap and recyclable non-metal selenium as a catalyst instead of the noble metal palladium;carbon monoxide as a carbonylation agent instead of virulent phosgene or one of its derivatives;and oxygen as an oxidant.The selenium-catalyzed oxidative carbonylation reaction of2-aminobenzyl alcohol proceeded efficiently in a single pot in the presence of triethylamine to afford l,4-dihydro-2H-3,l-benzoxazin-2-one in 87%yield.Furthermore,the selenium catalyst was readily recovered and recycled,affording a product yield of 80%after five cycles.

A facile synthesis of 2,3-dihydro-2-aryl-4(1H)-quinazolinones catalyzed by scandium(Ⅲ) triflate

2,3-Dihydro-2-aryl-4（1H）-quinazolinones were prepared in good yields via condensation of o-aminobenzamide with aldehydes promoted by a catalytic amount of Sc（OTf）3 under mild conditions.

Synthesis of Some Potential Antiangiogenic 1,3-Dihydro-1,3-dioxo-2H-isoindole Derivatives

Based on the structure-activity relationships of RGD-containing peptides, a series of 1,3-dihydro-1,3-dioxo-2H-isoindole derivatives were synthesized. All of them were first reported. Their structures were confirmed by spectral data and elemental analysis. Their ability to inhibit angiogenesis were evaluated in the chick embryo chorioallantoic membrane assay at 10-5 mol/L. Compounds 5b and 5e displayed obviously antiangiogenic activity.

Potassium iodide catalyzed reductive dehalogenation ofα-halo-ketones using Hantzsch ester diethyl 1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylate as reductant

In the presence of diethyl 1,4-dihydro-2,6-dimethylpyridine-3,5-dicarboxylate（DHP） and a catalytic amount of potassium iodide,severalα-halo ketones were easily reduced to the corresponding ketones in acetone media.The procedure presented here showed several merits such as short reaction time,practical experimental and isolated procedure,and excellent yields of products.

Synthesis,Crystal Structure and Cytotoxic Activities of 1-(Prop-2-yn-1-yl)-7,8-dihydro-1H-benzo[d][1,3]-thiazine-2,5(4H,6H)-dione Derivatives

The important synthetic precursor（Ⅲ）, 1-（prop-2-yn-1-yl）-7,8-dihydro-1Hbenzo[d][1,3]thiazine-2,5（4H,6H）-dione（C（11）H（11）NO2S）, was prepared through a three-component reaction, which was further transferred into cytotoxic triazoles by alkylation and ＂click＂ synthesis in satisfactory yields of 87%^95%. Their structures were characterized by IR, H-RESI-MS and NMR analysis. Meanwhile, the crystal of Ⅲ was obtained and determined by X-ray single-crystal diffraction. Crystal data： orthorhombic system, space group P212121, a = 5.189（4）, b = 8.661（6）, c = 23.498（17） A, V = 1056.2（13） A^3, Z = 4, F（000） = 464, Dc = 1.392 g/cm^3, μ =0.284 mm^-1, R = 0.0637 and wR = 0.1668 for 8182 independent reflections（R（int） = 0.1580） and 2166 observed ones（I 〉 2σ（I））.

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.

Synthesis of 5-Aryl-1, 2-dihydro-1-pyrrolizinones

In order to search for new potent anti-inflammatory and analgesic agents in pyrrolizinones, the title compounds were designed and synthesized. A series of the compounds were prepared with two different synthetic schemes. Some of the compounds showed remarkable anti-inflammatory and/or analgesic activities on mice.

A New Approach to 2,3-Dihydro-1H-1,5-Benzodiazepines from the Reaction of o-Nitrophenylazide with α,β-Unsaturated Ketones Promoted by Samarium Diiodide

o-Nitrophenylazide was reduced by SmI2 in anhydrous THF at room temperature to produce active intermediate 2 (samarium amide), "living" double-anion in situ which reacted smoothly with α，β-unsaturated ketones to afford 2,3-dihydro-1H-1,5-benzodiazepines in good yields under mild and neutral conditions.

Determination of Trace Silver( Ⅰ ) in Basic Aqueous Solution by Electrochemiluminescence of a New Reagent 6-(2-Hydroxy-4-Diethylaminophenylazo)-2,3-Dihydro-1,4-Phthalazine-1,4-Dione

The electrochemiluminescence (ECL) of a new reagent 6- (2-hydroxy- 4 diethy laminophenylazo)-2,3-dihydro-1 ,4-phthalazine-1,4-dione (HDEA) in a basic aqueous so lution was studied by using the apparatus designed by ourselves. Trace amounts of silver ( Ⅰ ) shows a significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the solution. The linear relationship between the light intensity and the concentration of silver( Ⅰ ) occurs in the range of 5. 0×10-8 to 3. 0×10-8 mol/L Ag(Ⅰ ) in a medium of KOH-KCl-HDEA (pH= 12. 8). The detection limit of the method is 2. 0×10-8 mol/LAg( Ⅰ ), and the r. s. d. for 1.0×10-7 mo)/L Ag ( Ⅰ ) is 5%. Of 21 metal ions concerned, only nickel( Ⅱ ), cerium( Ⅳ ) and cobalt( Ⅱ ) interfere the silver detection seriously; Ⅰ and Br also have some interference.

Synthesis and Crystal Structure of a New Quinazolinone Compound 2,3-Dihydro-2-(2-hydroxyphenyl)-3-phenyl-quinazolin-4(1H)-one

A new quinazolinone compound 2,3-dihydro-2-(2-hydroxyphenyl)-3-phenyl- quinazolin-4(1H)-one 3 ([C20H16O2N2]?C2H5OH, Mr = 362.42) and compound 2-(2-hydroxy- benzylidene-amino)-N-phenyl-benzamide 2 (C20H16O2N2, Mr = 316.34) were prepared from a precursor of 2-amino-N-phenyl-benzamide 1 (C13H12ON2, Mr = 212.25). Compound 3 was characterized by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombic, space group Pbca with a = 1.2889(11), b = 1.6170(14), c = 1.7729(15) nm, V = 3.695(6) nm3, Z = 8, F(000) = 1536, Mr = 362.42, Dc = 1.303 g/cm3, μ(MoKα) = 0.087 mm-1, R = 0.0447 and wR = 0.0879. The crystal structure analysis indicates that the title compound has a two-dimensional network structure formed by hydrogen bonds and electrostatic interactions.

Synthesis and Crystal Structure of Tert-butyl 4-[(E)-4-(1,3-Dioxo-1,3-dihydro-2H-isoindol-2-yl)-1-butenyl] Benzoate

The title compound tert-butyl 4-[（E）-4-（1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl）- 1-butenyl] benzoate has been synthesized and characterized by X-ray crystallography. It crystallizes in monoclinic, space group C2/c with a = 14.875（3）, b = 8.9796（13）, c = 34.736（6） A°, β = 95.981（4）°, V= 4614.4（14）A°^3, Z= 8, Dc = 1.213 g/cm^3, F（000） = 1792,μ（MoKα） = 0.084 mm^-1, R = 0.0602 and wR = 0.1445 for 4613 unique reflections with 2272 observed ones （I〉 2σ（I））. The results of crystal structure determination show that the title compound has a layer structure, and the two benzene rings in molecule are parallel to each other.

Study on the regioselective alkylation of 2-thiopyrimidine

Aim To investigate the alkylation of 2-thiopyrimidine. Methods Treating the starting material 2-thiopyrimidine with chloromethyl ethers via a procedure of K2CO3 in DMF or with alkyl halide in CH3ONa-CH3OH at room temperature, to obtain the corresponding regioselective 2-S-allkyl pyrimidines. The products were determined by JH NMR, 2D NMR, IR and MS spectra. Results 2-S-alkyl-pyrimidines were regioselectively synthesized. Conclusion In different conditions with different alkyl halides, 2- thiouracil could be converted into the corresponding 2-S-alkylpyrimidines regioselectively.

Vasorelaxant effect of 3,4-dihydro-2-(4-morpholinylmethy)-1(2H)-naphthalenone on the vascular smooth muscle of rabbits

The purpose of this study was to examine the relaxation effect of CY on the vascular smooth muscle （VSM） from rabbits. Experiments were carried out on isolated thoracic aorta of rabbits. CY （3 x 103 mM- 3 mM） could relax the VSM preparations pre-contracted by adrenaline （AD）, noradrenaline （NE）, high-K^＋ solution or BaCl2 with respective EC50 values of （0.3 1±0.11） mM, 0.19±0.03 mM, 0.20±0.04 mM and 0.25±0.04 mM. Moreover, CY （10-2 mM, 0.1 mM and 1 mM） inhibited norepinephrine （NE）, CaCl2 and KCl-induced vasoconstriction in a concentration dependent manner. The phasic contraction produced by NE was concentration dependently attenuated with CY （10^-2 mM, 0.1 mM and 1 mM） in calcium-free medium, similar to that caused by verapamil. The present findings suggest that CY relaxed thoracic aortic rings by blocking voltage-dependent Ca^2＋ channels. The inhibition of intracellular Ca^2＋ release may be one of the main vasorelaxant mechanisms of CY.

Eco-friendly synthesis of 2-substituted-2,3-dihydro-4(1H)-quinazolinones in water

2-Substituted-2,3-dihydro-4（1H）-quinazolinones were synthesized in high yield by condensation of 2-anthranilamide with aromatic aldehydes or ketones in refluxing water without catalyst.This protocol has advantages of high yield,simple work-up and environmental friendly procedure.

Reaction of 2,3-Dihydro-1,5-benzothiazepines and Phenylacetyl Chloride in the Presence of Triethylamine:A New Aspect on the Formation Mechanism of Dihydro-1,3-oxazin-4-one Derivatives

2a,4-Disubstituted 2,2a,3,4-tetrahydro-2-phenyl-1H-azeto[2,1-d][1,5]benzothiazepin-1-ones, as well as 2-substi- tuted 2,3-dihydro-3-phenylacetyl-2-styryl-benzothiazoles and 4a,6-disubstituted 3-benzyl-4a,5-dihydro-2-phenyl- 1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, were obtained from the reaction of 2,4-disubstituted 2,3-dihydro-1,5-benzothiazepines with phenylacetyl chloride in the presence of triethylamine. The mechanism for the formation of 4a,5-dihydro-1H,6H-[1,3]oxazino[2,3-d][1,5]benzothiazepin-1-ones, 2,3-dihydro-1,3-oxazin-4-one derivatives, was suggested.

Design, synthesis and MAO inhibitory activity of 2-(arylmethylidene)-2,3-dihydro-1-benzofuran-3-one derivatives

A series of 2-（arylmethylidene）-2,3-dihydro-1-benzofuran-3-one derivatives（aurones, 1–20） were synthesized and screened for their inhibitory activity against h MAO. Seventeen compounds（1–5, 7–17,19） were found to be selective towards h MAO-B, while two were non-selective（6 and 20） and one（18）selective towards h MAO-A. Compound 17（Ki = 0.10 0.01 mmol/L） was found to be equally potent and selective towards h MAO-B, when compared with the standard drug Selegiline（Ki = 0.12 0.01 mmol/L）.Nature and position of substitution in aryl ring at 2nd position of benzofuranone influences h MAO-B inhibitory potency, while their structural bulkiness influences selectivity between h MAO-A and h MAO-B.Molecular docking simulation was also carried out to understand the interaction of inhibitor with the enzyme at molecular level, and we found the docking results were in good agreement with the experimental values. Comparison of the activity profile of the aurones with their corresponding flavones reported earlier by our group revealed that there exists no difference in potency as well as selectivity.

Nitrative and oxidative DNA damage in intrahepatic cholangiocarcinoma patients in relation to tumor invasion

AIM： Nitrative and oxidative DNA damage such as 8-nitroguanine and 8-oxo-7,8-dihydro-2＇-deoxyguanosine （8-oxodG） formation has been implicated in initiation and/ or promotion of inflammation-mediated carcinogenesis. The aim of this study is to clarify whether these DNA lesions participate in the progression of intrahepatic cholangiocarcinoma. METHODS： We investigated the relation of the formation of 8-nitroguanine and 8-oxodG and the expression of hypoxia-inducible factor-1α （HIF-1α） with tumor invasion in 37 patients with intra-hepatic cholangiocarcinoma. RESULTS： Immunohistochemical analyses revealed that 8-nitroguanine and 8-oxodG formation occurred to a much greater extent in cancerous tissues than in non-cancerous tissues. HIF-1α could be detected in cancerous tissues in all patients, suggesting low oxygen tension in the tumors. HIF-1α expression was correlated with inducible niltric oxide synthase （iNOS） expression （r = 0.369 and P = 0.025） and 8-oxodG formation （r = 0.398 and P = 0.015）. Double immunofluorescence study revealed that iNOS and HIF-1α co-localized in cancerous tissues. Notably, the formation of 8-oxodG was correlated significantly with lymphatic invasion （r = 0.386 and P = 0.018）. Moreover, 8- nitroguanine and 8-oxodG in non-cancerous tissues were associated significantly with neural invasion （P = 0.042 and P = 0.026, respectively）. These results suggest that reciprocal activation between HIF-1α and iNOS mediates persistent DNA damage, which induces tumor invasiveness via mutations, resulting in poor prognosis. CONCLUSION： The formation of 8-nitroguanine and 8-oxodG plays an important role in multiple steps of genetic changes leading to tumor progression, including invasiveness.

A New Daphnane Diterpene from Daphne tangutica

A new daphnane diterpene was isolated from the root barks of Daphne tangutica Maxim. Its structure was elucidated as 1, 2α-dihydro-20-palimoyldaphnctoxin by the spectroscopic evidence including 2D-NMR.