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The synthesis, configuration, and conformation of cis ‐ and trans ‐3‐amino‐3,4‐dihydro‐1‐hydroxy‐4‐methylcarbostyrils and other configurationally related compounds
Author(s) -
Mccord Tommy J.,
Smith Sherrel C.,
Tabb David L.,
Davis Alvie L.
Publication year - 1981
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.5570180536
Subject(s) - chemistry , diastereomer , butyric acid , amino acid , stereochemistry , yield (engineering) , catalysis , proton nmr , organic chemistry , biochemistry , materials science , metallurgy
The cis ‐ and trans ‐3‐amino‐3,4‐dihydro‐1‐hydroxy‐4‐methylcarbostyrils (Ia and Ib) were synthesized by catalytic hydrogenation of erythro ‐ and threo ‐α‐amino‐β‐( o ‐nitrophenyl)butyric acid hydrochlorides, IIIa and IIIb, respectively, under acidic conditions. The free bases of IIIa and IIIb were catalytically hydrogenated under neutral conditions to yield the erythro ‐ and threo ‐α‐amino‐β‐( o ‐aminophenyl)butyric acids (VIa and VIb), which were converted by acidification to their corresponding lactams, cis ‐ and trans ‐3‐amino‐3,4‐dihydro‐4‐methylcarbostyrils, IIa and IIb. The erythro and threo isomers of α‐amino‐β‐( o ‐nitrophenyl)‐butyric acid were prepared and separated by liquid chromatography via a diastereomeric mixture of (V) of methyl α‐acetamido‐β‐( o ‐nitrophenyl)butyrates. The configurations and conformational assignments of the cyclic hydroxamic acids Ia and Ib were first established by analysis of the proton nmr spectra. In turn, the configurations of the o ‐nitroaromatic amino acids IIIa and IIIb were assigned as well as the other structurally related compounds (VIa, VIb, IIa and IIb) derived therefrom.