Vibrational spectroscopy of 5-amino-3-methyl-4-isoxazolecarbohydrazide and its N-deuterated isotopologue

Both spectral and structural studies of 5-amino-3-methyl-4-isoxazolecarbohydrazide (HIX) were done and compared to calculated parameters using ab initio OFT methods. A detailed interpretation of the infrared and Raman spectra of title molecule is reported on the basis of the calculated potential energy distribution (PED). The conformational search for possible conformers and tautomers of title compound has been conducted and widely discussed. N-deuterated isotopologue of 5-amino-3-methyl-4-isoxazolecarbohydrazide (HIXD) was synthesized to eliminate disturbing frequencies in carbonyl region of IR and Raman. Besides, N-deutaration enabled the unambiguous assignment some bands to specific vibrations. Moreover, the stability of the 5-amino-3-methyl-4-isoxazolecarbohydrazide arising from hyper conjugative interactions has been studied using natural bond orbital (NBO) analysis. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.