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Studies on indenopyridine derivatives and related compounds. II . Stereochemistry of 1‐substituted 9‐phenyl‐1,3,4,4a,9,9a‐hexahydro‐4‐hydroxy‐2 H ‐indeno[2,1 ‐b ] pyridines and their acetates
Author(s) -
Kurihara Takushi,
Hirano Hiroshi
Publication year - 1975
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.5570120201
Subject(s) - chemistry , piperidine , ring (chemistry) , stereochemistry , acetic anhydride , pyridine , chemical shift , group (periodic table) , medicinal chemistry , organic chemistry , catalysis
Chemical and catalytical reduction of 1‐methyl‐ or 1‐benzyl‐phenyl‐1,3,4,9‐tetrahydro‐2 H ‐indeno[2,1‐ b ]pyridin‐4‐ones (VIIa,b) afforded 1‐methyl‐ or 1‐benzyl‐9‐phenyl‐1,3,4,4a,9,9a‐ hexahydro‐4‐hydroxy‐2 H ‐indeno[2,1‐ b ]pyridines (IXa,b), which gave the corresponding acetates (Xa,b) by treatment with acetic anhydride and pyridine. Based upon a detailed study of 100 MHz nmr spectra of these compounds, it was concluded that the hydroxy group of IXa,b has an axial configuration taking B/C cis stable form which has the large aromatic group equatorial with respect to the piperidine ring, whereas the acetoxy group of Xa,b is equatorial taking an unfavorable B/C cis unstable form which has the large aromatic group axial with respect to the piperidine ring.