合成路线1

Amination of 5-bromo-2,4-dichloropyrimidine (VIII) with cyclopentylamine (IX) in EtOH gives 5-bromo-2-chloro-4-(cyclopentylamino)pyrimidine (X), which is then cyclized with crotonic acid (XI) by means of DIEA, TOTP, PdCl2(PhCN)2 in THF at 70 °C followed by treatment with Ac2O to yield the 8H-pyrido[2,3-d]pyrimidinone derivative (XII). Bromination of compound (XII) with Br2 in the presence of NaOAc in AcOH provides the 6-bromopyrido[2,3-d]pyrimidinone derivative (XIII), which is then coupled with the aminopyridine derivative (IV) in the presence of LiHMDS in toluene to afford intermediate (V). Condensation of the bromo derivative (V) with butylvinylether (XIV) in the presence of DIEA, PdCl2(dppf)2.CH2Cl2 complex in n-BuOH at 95 °C affords the 6-(1-butoxyvinyl)dihydropyrido[2,3-d]pyrimidine derivative (XV) . Finally, intermediate (XV) is treated with isethionic acid (XVI) —previously prepared by acidification of sodium isethionate (XVII) with HCl in i-PrOH in MeOH/H2O at 55 °C followed by TEA in MeOH .
The aminopyridine intermediate (IV) can be prepared by condensation of Boc-piperazine (XVIII) with 5-bromo-2-nitropyridine (XIX) in the presence of TEA in DMSO at 65-70 °C to give the nitropyridine derivative (XX), which is then reduced in the presence of H2 over Pd(OH)2/C in i-PrOH .
The key intermediate diarylamine adduct (V) can also be obtained directly by coupling aminopyridine derivative (IV) with the 2-methanesulfonylpyrido[2,3-d]pyrimidinone derivative (XXI) .