Analogs of cannabinoids: synthesis of some 7<i>H</i>-indolo-, 5<i>H</i>-imidazolo, 7<i>H</i>-benzimidazolo[1,2-<i>c</i>] [1,3]benzoxazines – novel ring systems

Abstract

Tetrahydrocannabinol 1, the active constituent of CannabissativaLinn, is a well-known CNS-active compound and introduction of a nitrogen atom at the ring junction of the pyran and alicyclic ring is of considerable interest. This prompted the synthesis of 7H-indolo[1,2-c] [1,3]-, 5H-imidazolo[1,2-C] [1,3],- and 7H-benzimidazolo[1,2-c] [1,3]-benzoxazine, a novel heterocyclic system. 2-(2′-Hydroxyphenyl) indoles, 2-(2′-hydroxyphenyl) imidazoles, and 2-(2′-hydroxyphenyl) benzimidazoles are suitable intermediates for the preparation of this type of benzoxazines, as the second heterocycle (ring B) can then be constructed by introduction of a methylene bridge between the hydroxyl of the 2′-hydroxy phenyl substituent and the imino group of the heterocyclic system.