Unexpected substitution of the acyl group in isothiazole-ring formation. Attempted conversion of 1-acyl-2,2-diaminoethylenes into 2-acyl-3,3-diaminoacrylonitriles
作者:Srinivasachari Rajappa、Mohan D. Nair、Bhagwan G. Advani、Ramaswami Sreenivasan
DOI:10.1039/p19810003161
日期:——
2-(Acylmethylene) hexahydropyrimidines (7) have been converted into the corresponding benzoyl isothiocyanate adducts (8), treatment of which with sulphuryl chloride gave the 3-chloroisothiazolo[2,3-a]pyrimidine (10) instead of the expected 3-acyl compound (9). Oxidation of the adduct (8c) by bromine gave the isothiazolo[2,3-a]-pyrimidine (9c) in low yield; this failed to undergo base-catalysed fragmentation
2-(酰基亚甲基)六氢嘧啶(7)已转化为相应的苯甲酰基异硫氰酸酯加合物(8),用硫酰氯处理可得到3-氯异噻唑并[2,3- a ]嘧啶(10),而不是预期的3-酰基化合物(9)。溴将加合物(8c)氧化后,异噻唑并[2,3- a ]-嘧啶(9c)的收率低;这未能进行碱催化的腈裂解(13c)。最后,通过与1-甲基-2-甲硫基-1,4,5,6-四氢嘧啶(12)缩合,由苯甲酰基-和2-巯基甲基-氰化物(11)制备α-酰基-α-氰基亚甲基六氢嘧啶(13)。 )。