KINETIC FORMATION AND EQUILIBRATION OF ISOMERIC KETONE DIMETHYLHYDRAZONE LITHIO ANIONS
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Deprotonation of (Z)-[1-13C]-3-pentanone dimethylhydrazone (DMH) ((Z)-l) by lithium diethylamide and lithium diisopropylamide in THF was studied by 13C NMR spectroscopy. Low regioselectivity was observed, and no isomerization of (Z)-l to (E)-1 occurred during the deprotonation reaction.Proton-transfer reactions between 3-pentanone DMH (6), heptanal DMH (7), and 3-heptanone DMH (10) and the DMH lithio anions formed by deprotonation of these DMH's at 0 C were studied by alkylation and GC analysis of the alkylated products. These reactions occurred with half-lives of 2 to 8 h, while the deprotonation of ketone DMH's with lithium dialkylamide bases was complete within 0.5 h at0 C. These results show that there is little preference for deprotonation syn or anti to the lone pair of the C=N nitrogen in otherwise equivalent methylene groups in acyclic ketone DMH's. 1980, American Chemical Society. All rights reserved.
JOURNAL OF ORGANIC CHEMISTRY
author list (cited authors)
LUDWIG, J. W., NEWCOMB, M., & BERGBREITER, D. E.
complete list of authors
LUDWIG, JW||NEWCOMB, M||BERGBREITER, DE