NOVEL SYNTHESIS OF HETEROCYCLIC ARYL AMIDINES

We have developed a novel amidine synthesis that allows the preparatio n of heterocyclic amidines that were previously unknown and difficult to prepare by published methods. The route involves the lithiation of heterocycles by the action of n-BuLi followed by reaction with carbon disulfide and trapping with methyl iodide, yielding a dithioate eater. The latter, when heated in 20% methanolic ammonia at 80 degrees C in a sealed tube provides the heterocyclic amidines directly, in good yie ld. The products are isolated by crystallization of the respective hyd rochloride salts. (C) 1998 Elsevier Science Ltd. All rights reserved.