127801-92-7Relevant articles and documents
Reaction of 2-Aminothiazoles with Reagents containing a C-Halogen and a C=O Electrophilic Centre
Compton, Victoria J.,Meakins, G. Denis,Raybould, Amanda J.
, p. 2029 - 2032 (2007/10/02)
Seven reagents of different types having in common a C-Hal and a C=O electrophilic centre have been used in a study of their reactions with 2-aminothiazoles.Three reagents, CHBrAc2 and ROCHBrCO2Et (R = Me, Ph), gave imidazothiazoles, thus providing useful routes to the 5-acetyl and 5-ethoxycarbonyl derivatives.Unexpectedly, the solvent (acetone) was involved in the reaction of the fourth reagent, CHBr(CO2Et)2, with 2-aminothiazole which led to 5,5-di(ethoxycarbonyl)-6,6-dimethyl-5,6-dihydroimidazothiazole (yield 81percent).With the last three reagents (AcCHBrNO2, BzCHBrCN and ICH2CO2C6H4NO2-p) the outcome was simpler, viz., the formation of 2-amidothiazoles.It is proposed that electrophilic attack by the endo-N of the 2-aminothiazole is the first step in all cases.This occurs at the C-Hal centre of the first four reagents and is followed by cyclisation to the exo-N.In the last three electrophiles the presence of the groups well suited to leaving as stabilised anions favours addition to the C=O group; the intermediates so formed subsequently isomerise to the more stable exo-N substituted products.
