13C nuclear magnetic resonance studies on pyrano- and dihydropyrano-1,3- diphenylprop-2-enones
作者:V. S. Parmar、S. K. Sharma、A. Vardhan、R. K. Sharma、S. Gupta、S. Malhotra、P. M. Boll
DOI:10.1002/mrc.1260300619
日期:1992.6
The 13C NMR spectra of 19 differently substituted pyrano- and dihydropyrano-1,3-diphenylprop-2-enones were recorded and the results are discussed. The data will be useful in the identification of new and natural chalcones.
New fragmentation pathways in the electron impact mass spectrometry of derivatized pyrano-1,3-diphenylprop-2-enones
作者:Virinder S. Parmar、Sunil K. Sharma、Anand Vardhan、Rakesh K. Sharma、Jørgen Møller、Per M. Boll
DOI:10.1002/oms.1210280106
日期:1993.1
AbstractThe fragmentation patterns of closely related chalcones, cinnamoylchromans and cinnamoylchromenes, are reported to be strikingly different. The mass spectra of the first group show peaks typical of the fragmentation of simple chalcones balanced by additional fragmentation routes competing effectively with the typical chalcone fragmentation. For the other group with the introduced double bond the fragmentation is considerably changed. Initial loss of a methyl group gives rise to formation of the base peak in three of four examples. The [M – CH3]+ ion decomposes further, eliminating a styrene yielding the m/z 187 ion. This process may be rationalized as a retro‐Diels–Alder fragmentation of a flavanone formed on intramolecular rearrangement of the molecular ion.
Parmar, V. S.; Vardhan, Anand; Sharma, S. K., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1994, vol. 33, # 1, p. 17 - 26
作者:Parmar, V. S.、Vardhan, Anand、Sharma, S. K.、Sharma, N. K.、Bisht, K. S.