Stereochemical assignment through intramolecular hydrogen bonded stabilized conformation about N-C (aryl) bond: An H-1 NMR study

One of the carbonyls of the succinimidyl ring in a tricyclic system, 2,3-(9 ',10'-dihydroanthracene-9', 10'-diyl)succinimide, is transformed into -CHOH group when reduced with sodium borohydride in methanol. The stereochemistr y of the -OH group has been ascertained to be exo by its capability of form ing an intramolecularly hydrogen bonded cyclic conformation about the N-C ( aryl) bond. Nsp(2) lone-electron pair of pyridyl moiety which remains only in anti-orientation would interact with 2-OH in exo-position. N-2 "-pyridyl and N-2 "-OCH3 phenyl moieties have been demonstrated to be effective prob es in stereochemical assignment.