Water → 1-[5-[7-Bromo-2-(ethylcarbamoylamino)-1,3-benzothiazol-5-yl]pyrimidin-2-yl]-4-methyl-piperidine-4-carboxylic acid

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Reaction Steps

To an ice-cold solution of ethyl 1-(5-(7-bromo-2-(3-ethylureido)benzothiazol-5-yl)pyrimidin-2-yl)-4-methylpiperidine-4-carboxylate (25 g, 45.7 mmol) in DMSO (50 mL) was added potassium tert-butoxide (25.5 g, 228 mmol). The resulting mixture was stirred at rt for 1 h. After completion of reaction (by TLC), water (250 mL) was added followed by extraction with EtOAc (2×250 mL). The organic layer was discarded; the pH of the aqueous layer was adjusted up to 4-5 and then extracted with hot EtOAc (3×250 mL). The combined organic layer was dried over Na2SO4, filtered and evaporated under reduced pressure. The residue thus obtained was triturated with ether to obtain the desired product as off-white solid (21 g, 88%). 1H NMR (DMSO-d6): δ 1.09 (t, J=7.20 Hz, 3H), 1.18 (s, 3H), 1.41 (m, 2H), 2.02 (m, 2H), 3.20 (m, 2H), 3.33 (m, 2H), 4.29 (m, 2H), 6.80 (br s, 1H), 7.70 (s, 1H), 7.87 (s, 1H), 8.76 (s, 2H), 10.95 (br s, 1H) and 12.46 (br, s, 1H). MS: 519.19 [M+H]+.

Provenance & Evidence