Methanesulfonic Acid → 1-cyclopentyl-3-methyl-6-(2-propoxyphenyl)-2H-pyrazolo[3,4-d]pyrimidin-4-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-cyclopentyl-3-methyl-5-amino-1H-pyrazole-4-carboxamide (3.98 g, 0.019 mol), 2-propoxybenzaldehyde (6.35 g, 0.038 mol), xylenes (150 ml) and methanesulfonic acid (0.5 ml) was heated at reflux for 39 hours with azeotropic removal of water. The reaction mixture was concentrated in vacuo and the residue was treated with 10% K2CO3 and ether. The layers were separated, the aqueous layer was extracted with ether and the combined ether layers were concentrated in vacuo. Analysis of the reaction mixture by TLC indicated that the reaction was not yet complete, therefore, the mixture was heated at 180° C. on an oil bath. The residue was dissolved in chloroform, and purified by column chromatography on silica gel eluting with hexane (100%) followed by ether (100%) to afford 2.67 g (41%) of 1-cyclopentyl-3-methyl-6-(2-propoxyphenyl)-pyrazolo[3,4-d]pyrimidin-4-one, m.p. 130°-132° C.

Provenance & Evidence