2-[1-芳酰基-1-(芳基偶氮) 亚甲基] 苯并噻唑啉的合成

本实验通过2-(1-芳甲酰基亚甲基)苯并噻唑啉和芳基重氮盐反应, 高产率地制得一系列2-[1-芳酰基-1-(芳基偶氮)亚甲基]苯并噻唑啉。     

Oxidation and chlorination reactions of perfluoroketene-N,S-acetals

The paper presents the results of the investigation of oxidation and chlorination reactions of perfluoroketene-N,S-acetals. Oxidation reactions of perfluoroketene-N,S-acetals proved to be dependent on the nature of oxidizing agent and led to the formation of corresponding sulfone in the case of m-chloroperbenzoic acid or amides of α-H-perfluoroalkane carboxylic acids in the case of tert-butyl hydroperoxide or hydrogen peroxide. Reaction of 1-tert-butylsulfanyl-2,3,3,4,4,4-hexafluoro-1-[N-methyl,N-((S)-α-methylbenzyl)amino]-but-1-ene with sulfuryl chloride demonstrated the chlorination of perfluoroketene-N,S-acetals as a new approach in the synthesis of chiral α-chloro perfluoroalkane carboxylic acid amides.     

Diastereoselectivity in Reactions of Lithiated 2-Phenylthiomethylthiotetrahydropyrans

Diastereoselectivities of up to 95:5 in alkylations of lithiated O,S,S-acetals are rationalized by the locked conformation of the five-membered ring caused by lithium-to-oxygen coordination. The relative configurations of the two diastereomers obtained in benzylation of lithiated 2-(phenylthiomethylthio)tetrahydropyran were confirmed by comparison with reference compounds of known stereochemistry obtained by benzylic reduction of crystalline hydroxyalkylated derivatives.     

Strong Axial Preference of 2-S Substituents in 3,4-Dihydro-2 H -1-Benzopyrans

The synthesis and crystal structure of a O,S,S-acetal derivative (1 R *,2 R *,2' S *)-1-(3,4-dihydro-2 H -1-benzopyran-2-ylthio)-2-phenyl-1-phenylthiopropan-2-ol 4 are reported. The 2-S-sidechain orientation in solution determined by OCHS signals in 1 H NMR spectra is mainly axial in all the 3,4-dihydro-2 H -1-benzopyran derivatives. Compound 4 crystallizes in the triclinic space group P 1 with an axial 2-S-sidechain and an intramolecular hydrogen bond between the OH and the ether oxygen with the O;;;O distance of 2.799(3) Å.