Deprotonation and regioselective addition of 2H-pyrazolo[3,4-c]quinolines to electrophiles.

The deprotonation and regioselective reaction of 2H-pyrazolo[3,4-c]quinolines with a variety of electrophiles is described. Electrophiles include benzaldehyde, DMF, carbon dioxide, and iodine. This method provides a direct route to a class of pharmacologically interesting compounds.

A kinetic study of product cleavage reactions from the solid phase by a biocompatible and removable cleaving reagent, HCl.

TFA has been widely used as a cleaving reagent in solid-phase organic synthesis. However, it is difficult to remove from the final product, and it is toxic to various cells. To search for an alternative, we studied the kinetics of HCl cleavage reactions of 18 resin-bound compounds on various linkers.

Quality control in combinatorial chemistry: determination of the quantity, purity, and quantitative purity of compounds in combinatorial libraries.

The quality of combinatorial libraries determines the success of biological screening in drug discovery programs. In this paper, we evaluate and compare various methods for measuring identity, purity, and quantity (yield) of combinatorial libraries. Determination of quantitative purity reveals the true library quality and often indicates potential quality problems before full-scale library production.

Kinetics study of amine cleavage reactions of various resin-bound thiophenol esters from marshall linker.

The kinetics of cleavage reactions of seven resin-bound thiophenol esters with three amines has been studied by single-bead FTIR. The reactivity of these seven thiophenol esters was dependent on their structures and could be summarized as follows: 5-benzimidazolecarboxylic thiophenol ester > alkyl thiophenol ester > aromatic thiophenol ester. The reactivity of three amines was summarized as follows: n-butylamine > 3,4-dimethoxyphenethylamine > 1-piperonylpiperazine.

Color test for the detection of resin-bound aldehyde in solid-phase combinatorial synthesis.

We report the development of a sensitive and specific color test for the detection of the presence of resin-bound aldehyde groups using 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (Purpald). Aldehyde resin turns dark-brown to purple after a 5 min reaction followed by a 10 min air oxidation period. Resins that possess other functional groups (i.