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Streptonigrin and related compounds III. Synthesis and microbiological activity of destrioxyphenylstreptonigrin and analogues
Author(s) -
Rao Koppaka V.
Publication year - 1977
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.5570140422
Subject(s) - chemistry , sodium azide , quinoline , halogenation , ring (chemistry) , tricyclic , stereochemistry , azide , combinatorial chemistry , organic chemistry
Synthesis of three tricyclic analogues of streptonigrin, based on the 2‐(2′‐pyridyl)quinoline‐5,8‐dione system and with the characteristic substitution pattern of rings A and C of streptonigrin is described. The C‐ring precursor, in the form of a substituted 2‐acetylpyridine was condensed with either 3‐hydroxy‐5‐methoxy‐2‐nitrobenzaldehyde or 3‐hydroxy‐4‐methoxy‐2‐nitrobenzaldehyde, followed by reductive cyclization and oxidation to the corresponding quinones 12 and 29 . The 7‐amino substitution was introduced in 12 via bromination and azidation. The 6‐amino substitution was introduced through direct reaction of 29 with sodium azide. Destrioxyphenylstreptonigrin 2 was twice as active and the 6‐amino‐7‐inethoxy analogue 4 was as active as streptonigrin in a microbiological assay. A 4′‐bromo analogue of 2 was 60% as active as streptonigrin.