Analogs of cannabinoids: synthesis of some 7H-indolo-, 5H-imidazolo, 7H-benzimidazolo[1,2-c] [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.

NMR analysis of a series of imidazobenzoxazines

“…The imidazobenzoxazines reported in this study were prepared in our laboratories as previously described 4…”

“…The synthetic route employed to obtain the imidazobenzoxazines 1–6 allowed to the formation of two regioisomers, separated and isolated. These new polycyclic heterocycles have been described by Mahesh only in 19854 and detailed information about 1 H and 13 C NMR signals of this class of compounds is still lacking. Thus, the present study deals with the complete 1 H and 13 C assignments of these structures, also focusing on the identification of the regioisomers obtained.…”

Synthesis and characterization of phenanthroimidazole derivatives for applications in organic electroluminescent devices

“…The starting material 2-(5-bromothiophen-2-yl)-1-(4-tert-butylphenyl)-1H-phenanthro [9,10-d] imidazole was prepared according to the literature. 15 Compounds 2a-2e were prepared through Suzuki coupling reactions. 16 2.2.…”

Chemoselective and diastereoselective synthesis of halogenated [1,3] oxazino [2,3‐a] isoquinoline derivatives

“…The chemistry of [1,3] oxazines has long kept a special place among N , O ‐heterocycles . Subunits of those, fused [1,3] oxazines with a bridgehead nitrogen atom and susceptible to biological and medicinal properties, are of interest to chemists .…”