tert-Butyl 4-(6-aminopyridin-3-yl)piperazine-1-carboxylate → 4-[6-(8-Cyclopentyl-6-ethoxymethyl-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidin-2-ylamino)-pyridin-3-yl]-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

8-Cyclopentyl-6-ethoxymethyl-2-methanesulfinyl-8H-pyrido[2,3-d]pyrimidin-7-one (1.0 g, 2.86 mmol) and 4-(6-amino-pyridin-3-yl)-piperazine-1-carboxylic acid tert-butyl ester (1.10 g, 3.95 mmol) were heated to reflux in toluene (10 mL) for 16 hours. The reaction mixture was cooled to room temperature and purified by silica gel chromatography to give 4-[6-(8-cyclopentyl-6-ethoxymethyl-7-oxo-7,8-dihydro-pyrido[2,3-d]pyrimidin-2-ylamino)-pyridin-3-yl]-piperazine-1-carboxylic acid tert-butyl ester as a yellow solid (0.140 g, 14.7%). 1H NMR δ (400 MHz, CDCl3) 8.59 (s, 1H), 8.26 (d, J=9.3 Hz, 1H), 7.97 (d, J=2.7 Hz, 1H), 7.6 (t, J=1.5 Hz, 1H), 7.38 (dd, J=2.7, 9.0 Hz, 1H), 5.89 (m, 1H), 4.55 (d, J=1.2 Hz, 1H), 3.66 (q, J=7.1 Hz, 2H), 3.60 (m, 4H), 3.11 (m, 4H), 2.34 (m, 2H), 2.07 (m, 2H), 1.88 (m, 2H), 1.69 (m, 2H), 1.48 (s, 9H), 1.30 (t, J=6.8 Hz, 3H).

Provenance & Evidence