6-bromo-8-cyclopentyl-5-methyl-2-(methylsulfinyl)pyrido[2,3-d]pyrimidin-7(8H)-one → tert-Butyl 4-(6-(6-bromo-8-cyclopentyl-5-methyl-7-oxo-7,8-dihydro-pyrido(2,3-d)pyrimidin-2-ylamino)-pyridin-3-yl)-piperazine-1-carboxylate

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Reaction Steps

A suspension of 6-bromo-8-cyclopentyl-2-methansulfinyl-5-methyl-8H-pyrido[2,3-d]pyrimidin-7-one (10.00 g, 0.027 mol, prepared as in Example 6 of WO 01/707041 which is incorporated here by reference) and 10.37 g (0.0373 mol) of 4-(6-amino-pyridin-3-yl)-piperazine-1-carboxylic acid tert-butyl ester in toluene (100 mL) was heated under nitrogen in an oil bath for 7 hours. Thin layer chromatography (SiO2, 10% MeOH/DCM) indicated that both starting materials remained. The suspension was heated under reflux for a further 18 hours. The resulting suspension was cooled to room temperature and filtered to give 4-[6-(6-bromo-8-cyclopentyl-5-methyl-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidin-2-ylamino)-pyridin-3-yl]-piperazine-1-carboxylic acid tert-butyl ester (5.93 g, 38%). mp>250° C. MS (APCI); M++1: Calc'd. 584.2. Found, 584.2.

Provenance & Evidence