Syntheses of β-lactams from acetic acids and imines induced by phenyl dichlorophosphate reagent
作者:Ana Arrieta、Fernando P. Cossio、Claudio Palomo
DOI:10.1016/s0040-4020(01)96484-1
日期:——
Among the reagents known to produce β-lactams from imines and acetic acids, only phenyl dichlorophosphate and 1-methyl-2-chloropyridinium iodide are suitable for the synthesis of vinylamino- β-lactams. Reaction of acetic acids with ethanolimine derivatives promoted by phenyl dichlorophosphate affords oxazolidines instead β-lactams. Protection of the hydroxyl group as the trimethylsilyl ether in the
N,N-Dimethylchlorosulfitemethaniminium chloride (SOCl2-DMF) a versatile dehydrating reagent.
作者:A Arrieta、J.M Aizpurua、C Palomo
DOI:10.1016/s0040-4039(01)81386-1
日期:1984.1
N,N-dimethylchlorosulfitemethaniminium chloride formed from thionyl chloride and dimethylformamide was found and efficient reagent for the synthesis of acyl azides fromcarboxylicacids and nitriles from oximes. It is also highly efficient for the directsynthesis of beta-lactams fromcarboxylicacids and imines avoiding the use of acidchlorides.
An improved method for the stereoselective synthesis of β-lactams from carboxylic acids and imines
作者:Gunda I. Georg、Peter M. Mashava、Xiangming Guan
DOI:10.1016/s0040-4039(00)74832-5
日期:1991.1
Carboxylic acids activated with Mukaiyama's reagent (2-chloro-N-methylpyridinium iodide) reacted with imines to produce β-lactams in good yields and with high stereoselectivity. The utilization of three equivalents of tripropylamine as the base was necessary to obtain high chemical yield and good stereoselectivity.