PROCESS FOR PREPARING 2-UNSUBSTITUTED IMIDAZOLES.

摘要

Prepn. of imidazoles unsubstituted at the 2-position and having formula (I), (where R1 and R2 are alkyl, H, cycloalkyl, aryl or aralkyl) comprises reaction of an alpha-hydroxy carbonyl compound of formula R1-CO-CHOH-R2 (II), with up to 2 moles of formamide at 100-170 deg.C., (pref. 130-140 deg.C) under an ammonia pressure of 5-15 kgf/cm2.G. The reaction produces formic acid, which after the reaction is removed either by driving it off at 100-250 deg.C., (pref. 120-200 deg.C.) or by esterifying it with an alcohol (pref. at 100-200 deg.C.). Any residue of formic acid remaining after this is removed by neutralisation with alkali (pref. an alkali(ne earth) hydroxide).