合成路线图解说明: The cyclization of 2-(3-bromophenyl)ethyl alcohol (I) with ethyl 3,3-diethoxypropionate by means of TiCl4 in dichlromethane gives racemic 2-(6-bromo-3,4-dihydro-1H-2-benzopyran-1-yl)acetic acid ethyl ester (III), which is regioselectively hydrolyzed by means of Amano P-30 lipase in apH 7 buffer yielding 2-(6-bromo-3,4-dihydro-1H-2-benzopyran-1(S)-yl)acetic acid (IV). The condensation of (IV) with 1-(4-methoxyphenyl)piperazine (V) by means of diethyl cyanophosphate in dichloromethane affords the acylated piperazine (VI), which is reduced with the complex BH3.THF in THF to 6-bromo-1(S)-[2-[4-(4-methoxyphenyl)piperazin-1-yl]ethyl]-3,4-dihydro-1H-2-benzopyran (VII). The reaction of (VII) with trimethylsilyl isocyante (VIII) by means of BuLiDMF gives the crboxamide (IX), which is treated with di-tert-butyl dicarbonate and dimethylaminopyridine (DMAP) in dichloromethane to yield the N,N-bis(tert-butoxycarbonyl) derivative (X). Finally, this compound is treated with an excess of methylamine. |