Hydrochloric Acid → 2,4-Diamino-6-[2-(4-carboxyphenyl)ethenyl]pyrido[2,3-d]pyrimidine

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Reaction Steps

Alternatively, 0.48 g of 2,4-diamino-6-[2-(4-tert-butoxycarbonylphenyl)ethenyl]pyrido[2,3-d]pyrimidine was added to a saturated solution of hydrogen chloride in 20 mL of nitromethane at 0°. The reaction mixture quickly became viscous and turned a deep yellow color and after a few minutes of stirring, a granular solid formed. After 1 hour of stirring, 50 mL of ether were added and the precipitate was collected by filtration. The collected solid was dissolved in 50 mL of 10% aqueous sodium carbonate. Acidification with acetic acid then resulted in the separation of a yellow solid which was collected by filtration and dried under reduced pressure; yield 0.31 g (92%) of 2,4-diamino-6-[2-(4-carboxyphenyl)ethenyl]pyrido[2,3-d]pyrimidine; NMR (Me2SO-d6) delta 6.75 (s, 2H), 7.35, 7.85 (AB q, 4H, J=9 Hz), 8.38 (s, 2H); IR (Nujol) 3400-2300, 3380, 3150, 1700, 1650, 1630, 1590 cm-1.

Provenance & Evidence