Synthesis of 3‐Aminopyrido[2,1‐a]isoquinolin‐4‐one Derivatives via Condensation of Azlactones with 1‐Alkyl‐3,4‐dihydroisoquinolines.

Reactions of available 1‐alkyl‐3,4‐dihydroisoquinolines with 4‐(2,2,2‐trifluoroacetyl)‐, 4‐acetyl‐ or 4‐(ethoxy‐methylene)‐2‐aryloxazol‐5(4H)‐ones were studied. A series of new 3‐amino‐6,7‐dihydro‐4H‐pyrido[2,1‐a]isoquinolin‐4‐one derivatives was synthesized. The intermediates formed as a result of the addition of azlactone to 1‐methyl‐3,4‐dihydroisoquinoline were isolated. The effect of the nature of the substituents, as well as the reaction conditions on the yield and structure of the title products was revealed. [ABSTRACT FROM AUTHOR]