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Curtius rearrangement in the 5‐phenyl‐1,4‐benzodiazepine series. Unprecedented participation by an imine nitrogen
Author(s) -
Bock Mark G.,
Dipardo Robert M.,
Carson Kenneth G.,
Freidinger Roger M.
Publication year - 1990
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.5570270329
Subject(s) - curtius rearrangement , chemistry , isocyanate , imine , benzodiazepine , ring (chemistry) , medicinal chemistry , stereochemistry , nitrogen , organic chemistry , catalysis , receptor , biochemistry , polyurethane
The previously unknown 3‐aminomethyl‐1,3‐dihydro‐5‐(2′‐fluorophenyl)‐2 H ,4‐benzodiazepin‐2‐one, 3a, was synthesized in two steps as a racemate. In the chiral series, 3( S )‐azidocarbonylmethyl‐1,3‐dihydro‐5‐phenyl‐2 H ‐1,4‐benzodiazepin‐2‐one, 12b, was prepared from N α‐Cbz‐β‐methylaspartate in five synthetic operations and subjected to Curtius rearrangement. The intermediate isocyanate was trapped intramolecularly by the 5‐imine nitrogen of the benzodiazepine ring in 12b. This unanticipated result runs counter to the generally held dictum that the isocyanate group has a strictly linear shape.