Synthesis of 1,2,3,4-Tetrahydro-1-Indolizinones and 3-Methyl-1,2-dihydro-1-Pyrrolizinones

4-(1-Pyrrolyl)butanenitrile(4), the key intermediate for the synthesis of 1,2,3,4-tetrahydro-1-indolizinone, was prepared with Clauson-Kass reation. When pyrrole reacted with 4-bromobutanenitrile in PEG-400 dimethyl ether catalyzed by NaOH, 3-(1-pyrrolyl)butanenitrile was obtained. The nitriles were converted into the corresponding ketones by Hoesch reaction. Some of the ketone derivatives were prepared.

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.

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.

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 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,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.

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.

Synthesis of N1-Substituted-3-aryl-4-alkyl-4, 5-dihydro-1H-1-pyra-zolethiocarboxamide as Novel Small Molecule Inhibitors of Cysteine Protease of T.cruzi

A series of N1-substituted-3-aryl-4-alkyl-4, 5-dihydro-1H-1-pyrazolethiocarboxamide were prepared from the Mannich bases of aryl ketones in good yields. Some derivatives were found to be active against the cysteine protease of T.cruzi..

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.

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.

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.

Biomimetic transformation of gentiopicroside to erythrocentaurin

Biomimetic transformation of gentiopicroside was carded out by β-glucosidase at pH 7.0 for 3 days at 37 ℃. Two products, erythrocentaurin and 5,6-dihydro-5-formyl-6-methyl-1H,3H-pyrano[3,4-c]pyran-1-one were isolated and identified by ^1H NMR, ^13C NMR, UV, IR, MS and elemental analyse. The possible mechanisms were discussed.

Design,synthesis,in vitro evaluation of tetrahydropyrimidine-isatin hybrids as potential antibacterial,antifungal and anti-tubercular agents

A series of 5-substitued-3-（5-（4-（furan-2-yl）-6-methyl-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidin-5-yl）-1,3,4-thiadiazol-2- ylimino）indolin-2-one derivatives were synthesized,characterized and were screened for anti-bacterial,anti-fungal and antitubercular activity.

Synthesis and biological evaluation of dihydrotriazine derivatives as potential antibacterial agents

A series of 1,4-dihydro-1,3,5-triazine derivatives were designed and synthesized and their antibacterial and antifungal activities were evaluated. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains（including multidrug-resistant clinical isolates） and Gramnegative bacterial strains, with minimum inhibitory concentrations（MICs） in the range of 2.1–181.2 mmol/L. Compounds 7a and 7c presented the most potent inhibitory activities against Grampositive bacteria（e.g., Staphylococcus aureus 4220）, Gram-negative bacteria（e.g., Escherichia coli 1924）,and the fungus Candida albicans 7535, with MICs of 2.1 or 4.1 mmol/L. Especially, compound 7a was the most potent, with an MIC of 2.1 mmol/L against four multidrug-resistant, Gram-positive bacterial strains.The cytotoxic activity of the compound 7a, 7c and 7f was assessed in HepG2 cells, and the results suggest that 1,4-dihydro-1,3,5-triazine derivatives bearing a 6-benzyloxynaphthalen moiety are interesting scaffolds for the development of novel antibacterial agents.

Cytotoxic diaporindene and tenellone derivatives from the fungus Phomopsis lithocarpus

Nine new compounds,including five natural rarely-occurring 2,3-dihydro-1H-indene derivatives named diaporindenes E−I(1−5),and four new benzophenone analogues named tenellones J−M(6−9)were isolated from the deep-sea sediment-derived fungus Phomopsis lithocarpus FS508.All the structures for these new compounds were fully characterized on the basis of spectroscopic data,NMR spectra,and ECD calculation and single-crystal X-ray diffraction analysis.The potential anti-tumor activities of compounds 1−9 against four tumor cell lines SF-268,MCF-7,HepG-2,and A549 were evaluated using the SRB method.Compound 7 exhibited cytotoxic activity against the SF-268 cell line with an IC50 value of 11.36μmol·L^(−1).