Interaction of 5-(Morpholin-4-Yl)-2-(4-Phthal-Imidobutyl)- and 5-(Morpholin-4-Yl)-2-(5-Phthal-Imidopentyl)-1,3-Oxazole-4-Carbonitriles with Hydrazine Hydrate

5-Morpholino-1,3-oxazole-4-carbonitriles bearing 4-phthalimidobutyl or 5-phthalimidopentyl substi-tuent at position 2 of the oxazole ring were synthesized. Upon reaction with hydrazine hydrate, 5-(morpholin-4-yl)-2-(4-phthalimidobutyl)-1,3-oxazole-4-carbonitrile formed the recyclization product (3-amino-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-2-yl)(morpholin-4-yl)methanone, whereas for 5-(morpholin-4-yl)-2-(5-phthalimidopentyl)-1,3-oxazole-4-carbonitrile, the reaction stops at the stage of 2-(5-aminopentyl)-5-(morpholin-4-yl)-1,3-oxazole-4-carbonitrile after removal of the phthalimido protecting group.