N-benzyl-4-methoxybenzenesulfonamide → Ethyl 4-[benzyl-(4-methoxybenzenesulfonyl)amino]-1,3-dimethyl-1H-pyrazolo[3,4-b] pyridine-5-carboxylate

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Reaction Steps

The mixture was heated in an oil bath at 50° C. overnight and then was heated in an oil bath at 100° C. for 1.5 days. The mixture was poured into 800 ml of water and extracted with ethyl acetate. The extract was washed with water, 2N citric acid, water, brine and dried (Na2SO4). The solvent was removed and the residue chromatographed on silica gel with hexane-ethyl acetate (2:1) as eluent to give 0.64 g of product as a solid, mp 170-172°. From a larger scale run of 5.07 g (0.02 mmol) of ethyl 4-chloro-1,3-dimethylpyrazolo[3,4-b]pyridine-5-carboxylate and 8.0 g (0.0289 mmol) of benzyl-(4-methoxybenzenesulfonyl) amine (as sodium anion) in 30 ml of 1-methyl-2-pyrrolidinone heated at 90° C. for 3 days there was obtained 3.65 g of product.

Provenance & Evidence