Parallel synthesis of 2-substituted 6-(5-oxo-1-phenylpyrrolidin-3-yl)pyrimidine-5-carboxamides.

A library of 24 6-(5-oxo-1-phenylpyrrolidin-3-yl)pyrimidine-5-carboxamides 10{1,2; 1-12} was prepared by a parallel solution-phase approach. The synthesis comprises a five-step transformation of itaconic acid (11) into 1-methyl and 1-phenyl substituted 6-(5-oxo-1-phenylpyrrolidin-3-yl)pyrimidine-5-carboxylic acids 17{1,2} followed by parallel amidation of 17{1,2} with a series of 12 aliphatic amines 18{1-12} to afford the corresponding carboxamides 10 in good overall yields and in 80-100% purity.

Bis-enaminone based parallel solution-phase synthesis of 1,4-dihydropyridine derivatives.

Two variations of a parallel solution-phase synthesis of N-substituted dimethyl 4-oxo-1,4-dihydropyridine-3,5-dicarboxylates 4 and methyl 3-oxo-3,5-dihydro-2H-pyrazolo[4,3-c]pyridine-7-carboxylates 9 from dimethyl acetone-1,3-dicarboxylate (1) were developed. The first synthetic method comprises preparation of the bis-enaminone reagents 2 and 8 and their cyclization with primary amines 3 via double substitution of both dimethylamino groups to give dihydropyridines (DHPs) 4 and 9, respectively. Another variation consists of preparation of the monoenaminone reagents 5 and 10, followed by substitution of the dimethylamino group with primary amines 3, and cyclization of the so formed intermediates 6 with N,N-dimethylformamide dimethylacetal (DMFDMA). In this manner, a library of 46 analytically pure compounds, 24 intermediates 6, 11, and 13, and 22 final dihydropyridines 4 and 9 was obtained employing just a simple filtration workup.

Diversity-oriented synthesis of 1-substituted 4-aryl-6-oxo-1,6-dihydropyridine-3-carboxamides.

A simple five-step diversity-oriented synthesis of 1-substituted 4-aryl-6-oxo-1,6-dihydropyridine-3-carboxamides was developed. Treatment of dimethyl 2-((dimethylamino)methylidene)-3-oxopentanedioate with twenty primary amines gave 1-substituted methyl 4-hydroxy-6-oxo-1,6-dihydropyridine-3-carboxylates. Transformation into the corresponding 4-tosyloxy and 4-chloro derivatives, followed by Suzuki-Miyaura arylations gave a series of eleven N-substituted methyl 4-aryl-6-oxo-1,6-dihydropyridine-3-carboxylates. Combinatorial screening was employed to establish suitable reaction conditions for Suzuki-Miyaura arylation of N-alkylpyridones. Hydrolysis of the esters followed by parallel solution-phase amidation of the corresponding carboxylic acids with primary and secondary amines furnished a library of seventeen final products.