Condensed Isoquinolines. Part 16. Enamine Properties of Benzo[4,5]imidazo[1,2‐b]isoquinolin‐11(5H)‐one in Terms of Its Acylation Reactions.

Abstract

Fused pyridine derivatives R 0450Condensed Isoquinolines. Part 16. Enamine Properties of Benzo[4,5]imidazo[1,2-b]isoquinolin-11(5H)-one in Terms of Its Acylation Reactions. -The acylation direction of the title compounds (I) depends on the nature of the carboxylic acid chloride (II) used leading either to C6-acylation products (III) or to a mixture of compounds (III) with N5-acylation products (IV). The cyclization of compound (IIIb) in the presence of iPr-ONa is accompanied by fission at the N6-C7 bond, while the use of NEt3 allows to prepare the desired cyclopentafluorene (VII) in good yield. The reaction of compound (I) with Ar-NCO gives rise to the 6-carbamoyl derivatives (X), whereas the analogous reaction with Ph-NCS leads unexpectedly to the dimeric product (XI).-(POTIKHA, L. M.; SHKILNA, N. V.; KISIL, V. M.; KOVTUNENKO, V. O.; Chem. Heterocycl. Compd. (N. Y.) 40 (2004) 5, 603-615; Taras Shevchenko Kiev. Natl. Univ., Kiev 252601, Ukraine; Eng.) -R. Staver