合成路线1

Horner-Emmons condensation of 4-nitrobenzophenone (IX) with triethyl phosphonoacetate produced a 2:1 mixture of Z and E nitrophenylcinnamic esters (XI) and (X). Alternatively, the desired Z isomer was obtained in a more favorable 8:1 ratio by condensation of (IX) with ethyl (trimethylsilyl)acetate under Peterson reaction conditions. Ester hydrolysis in the mixture (X) + (XI) with K2CO3 in aqueous methanol gave the corresponding mixture of carboxylic acids (XII). Optionally, the pure Z isomer could be isolated by recrystallization from EtOAc. DCC coupling of piperidine (VIII) with either the pure Z-isomer or the Z/E-mixture of carboxylic acids (XIIa-b) gave rise to the respective Z/E isomeric amides (XIIIa-b). After catalytic hydrogenation of the nitro group of (XIII), the required Z-(4-aminophenyl)cinnamamide isomer (XIV) was isolated by column chromatography. Finally, diazotization of (XIV), followed by coupling of the resultant diazonium salt (XV) to salicylic acid, furnished the title diazo compound.