A. Srivastava et al., STEREOCHEMISTRY OF THE ADDITION PRODUCT OF N-AMINOSUCCINIMIDE MOIETY TO AN ACETYLENIC ESTER, Bulletin of the Chemical Society of Japan, 67(5), 1994, pp. 1386-1389
H-1, C-13 NMR and X-ray crystallography have demonstrated the azomethi
ne structure of the addition product obtained from -2,3-(9,10-dihydro-
9,10-anthracenediyl)succinimide and diethyl acetylenedicarboxylate. Th
e exo cyclic nitrogen exists in sp2-state and its lone pair lies in an
ti orientation while the diethyl succinate moiety has been demonstrate
d to be syn to the cage and orthogonal to the succinimide plane. On ac
etylation the product is transformed into N-acetyl derivative which ex
hibits restricted rotation about N-N bond and a preferred conformation
with N-acetyl in syn-orientation.