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The utilization of chemical shift and spin‐lattice (T 1 ) relaxation time data for the discrimination of isomeric indenoisoxazoles
Author(s) -
Womack Charles H.,
Gampe Robert T.,
Lemke B. Kaye,
Sawhney Kailash N.,
Lemke Thomas L.,
Martin Gary E.
Publication year - 1982
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.5570190524
Subject(s) - chemistry , hydroxylamine , oxime , chemical shift , relaxation (psychology) , lattice (music) , spin–lattice relaxation , computational chemistry , medicinal chemistry , organic chemistry , condensed matter physics , paramagnetism , psychology , social psychology , physics , acoustics
Treatment of 2‐pivaloyl‐1,3‐indandione with hydroxylamine leads to the formation of a pair of isomeric indenoisoxazoles, the product formed dependent upon the cyclization conditions. Under acidic conditions, 8‐ t ‐butylindeno[1,2‐c]isoxazol‐7‐one ( 5 ) is formed while under neutral or basic conditions, an oxime, 2 , is generated which may then be cyclized under acidic conditions to give 3‐ t ‐butylindeno[1,2‐ c ]isoxazol‐4‐one ( 4 ). Although these isomeric indenoisoxazoles may be discriminated by chemical means, we were interested in developing an unequivocal method for distinguishing these and potentially other isomeric pairs by spectroscopic means. A 13 C‐nmr based method for the discrimination of these isomers which is based on the utilization of chemical shift arguments and spin‐lattice relaxation data is thus presented.