... (6) See: Clapp, L. B. "Advances in Heterocyclic Chemistry"; Ka- tritzky ... Without base, no reaction took place. With organic bases such as triethylamine and 1,4-diazabicyclo- [2.2.2]octane, no evidence of reaction was observed. ... See: Korbonits, D.; Bakb, E. M.; Korvith, K. J. Chem. ...