3-Amino-thio-acrylamide prodn. - comprises heating thioacetamide with tris-aminomethane or orthoformate and amine

摘要

Prodn. of 3-amino-thioacrylamides of formula R4R5N-CH=CR1-C(S)-NR2R3 (I) comprises reacting a thioacetamide of formula R1CH2-C(S)-NR2R3 (II) with a) a trisaminomethane of formula HC(NR4R5)3 (III) or b) an orthoformate HC(OR6)3 (IV) and an amine HNR4R5 (V) at an elevated temp.. R1 = H; alkyl; aryl; or heteroaryl; R2-R5 = H; alkyl; or aryl; or R2+R3 or R4+R5 = alkylene opt. contg. a hetero atom (e.g. N, O or S); R6 = alkyl. USE/ADVANTAGE - (I) are intermediates for pharmaceuticals, e.g. 3-aminopyrrole anticonvulsants known from EP 0431371. In contrast to known processes using thioacetamides and formamide chlorides described e.g. in DD 206990, acidic by-prods. are not formed and hydro-perchlorates are not required for prod. isolation. Further, the method gives (I) in high yields (e.g. 68.6-99%) in short reaction times and provides access to certain cpds. (I) (unspecified) which previously could not be prepd. or could be prepd. only in impure form. Again, the method provides an economical and environmentally friendly recycling procedure for the prepn. of (III), as this liberates (V) on heating.