A new synthetic route to 2-alkyl-4-aryl-1(2H)-isoquinolones and 2-alkyl-4-aryl-1,2,3,4-tetrahydroisoquinolines

Stereoelectronic Features of a Complex Ketene Dimerization Reaction

The amidation reaction of a tetrahydroisoquinolin-1-one-4-carboxylic acid is a key step in the multi-kilogram-scale preparation of the antimalarial drug SJ733, now in phase 2 clinical trials. In the course of investigating THIQ carboxamidations, we found that propanephosphonic acid anhydride (T3P) is an effective reagent, although the yield and byproducts vary with the nature and quantity of the base. As a control, the T3P reaction of a 3-(2-thienyl) THIQ was performed in the absence of the amine, and the products were characterized: among them are three dimeric allenes and two dimeric lactones. A nucleophile-promoted ketene dimerization process subject to subtle steric and stereoelectronic effects accounts for their formation. Two novel monomeric products, a decarboxylated isoquinolone and a purple, fused aryl ketone, were also isolated, and mechanisms for their formation from the ketene intermediate are proposed.

Palladium-catalysed stereoselective synthesis of 4-(diarylmethylidene)-3,4-dihydroisoquinolin-1(2H)-ones: expedient access to 4-substituted isoquinolin-1(2H)-ones and isoquinolines

Palladium-catalysed stereoselective synthesis of 4-(diarylmethylidene)-3,4-dihydroisoquinolin-1(2H)-ones and their straightforward transformations to 4-substituted isoquinolin-1(2H)-ones and isoquinolines are described.

First synthesis and pharmacological evaluation of benzoindolizidine and benzoquinolizidine analogues of alpha- and beta-peltatin

The benzoindolizidine and quinolizidine analogues of alpha- and beta-peltatin were designed and synthesized by two different synthetic routes involving as the key step the Bischler-Napieralski cyclization of suitably substituted N-acyl-2-arylmethylpyrrolidine and -piperidine derivatives. The in vitro biological activity of these analogues as well as some of their derivatives was subsequently evaluated.