Chlorination chlorosuccinimide, imine

Secondary allylic amines 184 have been prepared from aldehydes 181 (R1 = H, Me or Ph R2 = Me, Et or H) by the following sequence treatment with an amine R3NH2 (R3 = i-Pr, t-Bu, cyclohexyl or PhCH2) yields an imine 182, which is chlorinated by N-chlorosuccinimide. Dehydrochlorination of the resulting chloro compound with potassium t-butoxide gives an allylic imine 183, which is reduced to the product by means of methanolic sodium borohydride191. 

The general method used for the preparation of enamides is the acylation of the imine624-627. The imine may be prepared by usual methods and also by chlorination of the amino group of an amine with N-chlorosuccinimide, and subsequent dehydrochlorination of the N-chloroamine62 8,629 (equation 43). 

A convenient way selectively to introduce a chlorine atom into the methyl group of a methyl ketone has been developed. It involves treatment of the imine, formed from the reaction of the methyl-keto-group with ethanolamine, with Af-chlorosuccinimide (see Part II, Chapter 1, ref. 311 and also refs. 149-151 and 156). Various 3-trifluoromethyl derivatives have been prepared by photolytic addition of trifluoroiodomethane across the A -double-bond. ... 

While for the synthesis of synoxazolidinone A (1), aldehyde 12 was chlorinated by using NCS (A-chlorosuccinimide) and stoichiometric amoimt of proline to obtained product 16 (Scheme 2). 2,4-Dimethoxybenzyl amine 13 was treated with chlorinated aldehyde 16 to make imine and then it was treated with acyl chloride 14 to perform acylation /cyclization cascade reaction. It yielded cyclized product 17 in a diastereomeric ratio of 4 1, which upon deprotection with TFA gave synoxazolidinone A (1). Further, analogues of synoxazolidinones A (1) and B (2) were prepared and screened for their antimicrobial activities as well [14],... 

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