| 1H-Benzotriazole is a versatile synthetic auxiliary, and has widely been applied to many organic syntheses. In our continuous work on the methodology, we have developed convenient and efficient methods for preparation of heterocyclic compounds.; In chapter 2, formation of imidazolidine rings by the Mannich reaction involving 1H-benzotriazole as a nucleophile is described, and followed by nucleophilic substitution of the benzotriazole group utilizing Grignard reagents to give unsymmetrical imidazolidines.; In chapter 3, the study of the imidazolidines was further expanded to preparation of multi-cyclic compounds hexahydroimidazo[1,5-b]isoquinolines and tetrahydroimidazo[1,5-b]isoquinolin-1(5H)-ones. These heterocycles are synthesized via iminium cation cyclizations in the presence of AlCl3.; In chapter 4, N-acylbenzotriazole is introduced as neutral acylating reagents for the preparation of primary, secondary, and tertiary amides. Reaction of N-acylbenzotriazoles with various amines under mild conditions is discussed.; In chapter 5, syntheses of di-, tri-, and tetra-peptides is demonstrated utilizing N-(Z-aminoacyl)benzotriazoles with unprotected amino acids in aqueous solution. N-(Z-Aminoacyl)benzotriazoles are prepared from N-Z-amino acids and an intemediate obtained by reaction of 1H-benzotriazole and thionyl chloride.; In chapter 6, N-acylbenzotriazoles are applied to C-acylatinn under Friedel-Crafts conditions using heterocyclic compounds such as pyrrole, N-methylpyrrole, indole, N-methylindole, 2-methylfuran, and thiophene. This method provides heteroaromatic ketones, and is especially useful when the acid chlorides corresponding to N-acylbenzotriazoles are not readily available. |
