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Mannich reactions. Synthesis of 4,5‐dihydropyrrolo[l,2‐a]quinoxalines, 2,3,4,5‐tetrahydro‐l H ‐pyrrolo[l,2‐a] [l,4]diazepines and 5,6‐dihydro‐4 H ‐pyrrolo[ 1,2‐a] [ 1,4]benzodiazepines
Author(s) -
Raines Stephen,
Chai Sie Yearl,
Palopoli Frank P.
Publication year - 1976
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570130406
Subject(s) - chemistry , hydrochloric acid , pyrrole , medicinal chemistry , hydrochloride , base (topology) , organic chemistry , mathematical analysis , mathematics
l‐(2‐Aminophenyl)pyrrole (I) and l‐[2‐(aminomethyl)]phenylpyrrole hydrochloride (III) undergo cyclization reactions with aldehydes and ketones to form 4,5‐dihydropyrrolo[l,2‐a]‐ quinoxalines and 5,6‐dihydropyrrolo[l,2‐a][l,4]benzodiazepines, respectively. It was also found that the use of the free base of compounds corresponding to III do not cyclize directly but lead instead to the intermediate Schiff bases which are subsequently cyclized to the desired benzodiazepines by treatment with hydrochloric acid.