Hydrochloric Acid → N-(1-methyl-1-phenylethyl)-3-[(thiophene-3-carbonyl)amino]-1H-pyrazolo[4,3-d]thiazole-5-carboxamide

Participants

Reaction Conditions

Reaction Steps

0.16 g (0.32 mmol) of tert-butyl 5-(1-methyl-1-phenylethylcarbamoyl)-3-[(thiophene-3-carbonyl)amino]-1H-pyrazolo[4,3-d]thiazole-1-carboxylate dissolved in 7 ml of ethanol is placed in a 100 ml round-bottomed flask. 1.6 ml (6.4 mmol) of a 4M solution of hydrochloric acid in dioxane are then added and the reaction mixture is stirred for 15 hours at 25° C. A further 1.6 ml (6.4 mmol) of 4M solution of hydrochloric acid in dioxane are then added and the mixture is stirred for 15 hours at 25° C. The reaction medium is then concentrated to dryness under reduced pressure (40° C.) and the residue is taken up in 30 ml of dichloromethane and 30 ml of water, and basified with 0.1N sodium hydroxide solution. The emulsion obtained is resorbed by saturation with sodium chloride. After separation of the phases by settling, the organic phase is dried over magnesium sulfate and concentrated to dryness under reduced pressure (40° C.). The residue is purified by flash chromatography (msilica=30 g; eluent: 95/5 dichloromethane/methanol). 0.104 g of N-(1-methyl-1-phenylethyl)-3-[(thiophene-3-carbonyl)amino]-1H-pyrazolo[4,3-d]thiazole-5-carboxamide is thus obtained in the form of a cream-coloured foam. m.p.K=221° C. 1H NMR (400 MHz, DMSO-d6): δ ppm 1.70 (s, 6H); 7.20 (t, J=7.5 Hz, 1H); 7.31 (t, J=7.5 Hz, 2H); 7.41 (d, J=7.5 Hz, 2H); 7.69 (m, 2H); 8.46 (broad s, 1H); 8.53 (broad s, 1H); from 10.0 to 15.0 (very broad m, 2H).

Provenance & Evidence