[Studies on pyrazine derivatives. XXVI. Synthesis and tuberculostatic activity of N-pyrazinylthiourea]

2-Amino-3-chloropyrazine and 2-amino-6-chloropyrazine were reacted with appropriate sodium alkoxides to give 2-aminopyrazine derivatives with the methoxy, benzyloxy, chlorobenzyloxy, dichlorobenzyloxy, bromobenzyloxy or dibromobenzyloxy group at positions 3 and 6 (I-XIV). The obtained compounds were converted into N-pyrazinyl-N'-benzoylthioureas (XV-XXXI) by reacting with benzoyl isothiocyanate. Their hydrolysis yielded N-pyrazinylthioureas XXXII-XLVII. Analogical reactions of alkoxyaminopyrazines with p-chlorophenyl isothiocyanate or 2,6-dichlorophenyl isothiocyanate afforded corresponding N-pyrazinyl-N'-(p-chlorophenyl)thioureas and N-pyrazinyl-N'- (2,6-dichlorophenyl)thioureas (XLVIII-LVIII). The obtained compounds were found to display tuberculostatic in vitro activity with MIC values from 8 meg/cm3 to 1000 mu meg/cm3.