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Zhang Y Zhang X Zhou J Song B Bhadury PS Hu D Yang S 《Journal of separation science》2011,34(4):402-408
The direct HPLC enantioseparation of a novel series of chiral pyridazin-3(2H)-one derivatives with α-aminophosphonate moiety was performed on two immobilized polysaccharide chiral stationary phases (Chiralpak IA, Chiralpak IC) using n-hexane (n-Hex)/dichloromethane (DCM) mobile phase with 5% alcohol additive. Good baseline separation of the enantiomers was achieved using amylose tris-(3,5-dimethylphenylcarbamate) chiral stationary phases (Chiralpak IA) on analytical scale. The analytical method was further scaled up to semi-preparative loading to obtain small amounts of both the enantiomers of pyridazin-3(2H)-one derivative. The semi-preparative resolution of all compounds was successfully achieved with n-hexane/dichloromethane/ethanol (EtOH) as mobile phase using a semi-preparative Chiralpak IA column. The first fractions were isolated with purities of >99.9% (enantiomeric excess (e.e.), and the second fractions were obtained with purities of >98.2% (enantiomeric excess). The assignment of the absolute configuration was established for the F1 fraction of compound a-2 by single-crystal X-ray diffraction method. 相似文献
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Peng Lin Baoan Song Pinaki S. Bhadury Deyu Hu Yuping Zhang Linhong Jin Song Yang 《中国化学》2011,29(11):2433-2438
Mannich reactions of imine with acetylacetone were effectively catalyzed by the modified chiral cinchona alkaloid‐derived thiourea. The reactions led to chiral β‐amino carbonyl compounds in high yields and good enantioselectivities. The study demonstrated for the first time that Mannich reactions of unmodified acetylacetone with heterocyclic imine derived from benzothiazole can be promoted by chiral bifunctional organocatalyst. 相似文献
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Chen Z Xu W Liu K Yang S Fan H Bhadury PS Hu DY Zhang Y 《Molecules (Basel, Switzerland)》2010,15(12):9046-9056
Starting from 4-chlorobenzoic acid, 10 new 5-(4-chlorophenyl)-N-substituted-N-1,3,4-thiadiazole-2-sulfonamide derivatives were synthesized in six-steps. Esterification of 4-chlorobenzoic acid with methanol and subsequent hydrazination, salt formation and cyclization afforded 5-(4-chlorophen-yl)-1,3,4-thiadiazole-2-thiol (5). Conversion of this intermediate into sulfonyl chloride 6, followed by nucleophilic attack of the amines gave the title sulfonamides 7a-7j whose structures were confirmed by NMR, IR and elemental analysis. The bioassay tests showed that compounds 7b and 7i possessed certain anti-tobacco mosaic virus activity. 相似文献
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In this paper we investigate the following problem: Given two convex Pin, and Pout where Pin is completely contained in Pout, we wish to find a sequence of ‘guillotine cuts’ to cut out Pin from Pout such that the total length of the cutting sequence is minimized. This problem has applications in stock cutting where a particular shape or design (in this case the polygon Pin) needs to be cut out of a given piece of parent material (the polygon Pout) using only guillotine cuts and where it is desired to minimize the cutting sequence length to improve the cutting time required per piece. We first prove some properties of the optimal solution to the problem and then give an approximation scheme for the problem that, given an error range δ, produces a cutting sequence whose total length is atmost δ more than that of the optimal cutting sequence. Then it is shown that this problem has optimal solutions that lie in the algebraic extension of the field that the input data belongs to — hence due to this algebraic nature of the problem, an approximation scheme is the best that can be achieved. Extensions of these results are also studied in the case where the polygons Pin and Pout are non-convex. 相似文献
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Yi Jin Baoan Song Deyu Hu Xiangyang Li Pinaki S Bhadury Zhenchao Wang Song Yang 《Chemistry Central journal》2011,5(1):1-4
Background
Heteronucleophiles as well as carbanionic reagents can be used to react with α-amido sulfones, thus giving the opportunity to prepare a large array of amino derivatives. Since, novel 1,3,4-oxadiazole-2-thiol derivatives can serve as potent nucleophiles, we employed 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the nucleophilic source of nitrogen in the reaction with α-amido sulfones.Results
A series of N-substituted benzamides bearing 1,3,4-oxadiazol unit were prepared for the first time by the reaction of in situ generated protected imine from α-amido sulfones with 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the source of nitrogen nucleophile. Some of the synthesized products displayed favourable antiviral activity against cucumber mosaic virus (CMV) in preliminary antiviral activity tests. The title compounds 5c, 5o and 5r revealed curative activity of 42.2%, 48.7% and 40.5%, respectively against CMV (inhibitory rate) compared to the commercial standard Ningnanmycin (53.4%) at 500 μg/mL.Conclusion
A practical synthetic route to N-benzoyl-α-amido sulfones by the reaction of 5-subsititued phenyl-1,3,4-oxadiazole-2-thiols as the source of nitrogen nucleophiles with in situ generated protected imine from N-benzoyl-α-amido sulfones is presented. The reaction catalyzed by an inorganic base has considerable significance to exploit the potential of α-amido sulfones in organic synthesis. 相似文献17.
Jian Wu Song Yang Bao‐An Song Pinaki S. Bhadury De‐Yu Hu Song Zeng Hua‐Peng Xie 《Journal of heterocyclic chemistry》2011,48(4):901-906
A series of novel neonicotinoid analogs containing an amide moiety were synthesized, characterized, and subsequently evaluated for their insecticidal activity. According to the preliminary bioassay, the compounds 6c , 6e , 6f , 6j , 6n , and 6r exhibited > 50% activity against Nilaparvata lugens at 100 mg/L. Amongst the active compounds, 6f and 6r revealed insecticidal activities similar to that displayed by standard buprofezin. J. Heterocyclic Chem., (2011) 相似文献
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