Unexpected Formation of 1,2‐Dihydro‐2‐azolyl‐ and ‐azinylisoquinolines by the Reduction of the Corresponding Isoquinolinium Salts with Sodium Borohydride in Methanol.

Abstract

Surprisingly, the reduction of isoquinolinonium chlorides (I) bearing an electron-withdrawing group (heterocycle) in position 2 of the isoquinolinium moiety affords 1,2-dihydroisoquinoline derivatives. These results are corroborated by reduction of 2-phenylisoquinolines like (If) and (III) having both, electron withdrawing and donating groups on the phenyl moiety. -(PRAUDA, I.; TOTH-LAURITZ, M.; REITER, J.; J. Heterocycl. Chem. 41 (2004) 6, 915-929; EGIS Pharm. Ltd., H-1475 Budapest, Hung.; Eng.) -Bartels 19-163