Cyclic guanidines. IV. Synthesis of hypoglycemic N-benzhydryl bicyclic guanidines.

Abstract
N-benzhydryl bicyclic guanidines (12) were synthesized. The key intermediates, 1-benzhydryl-2-N- or 3-(.omega.-hydroxyalkyl)-2-imino-1,3-diazacycloalkanes (4) and (9) were prepared. The intramolecular cyclization of 4 to 12 resulted in low yield. Intramolecular cyclization of 9 to 12 was successful. Imidazo[1,2-a][1,3,5]oxadiazocine derivative (11), a new ring system, and N1-benzhydryl-N1-[2-(1-pyrrolidinyl)ethyl]urea (13) were isolated as byproducts. The N-benzhydryl bicyclic guanidines (12) showed potent hypoglycemic activity in rats.