合成路线1

The starting phenylethylamine (I) is prepared by condensation of N-formyl-5-bromo-3,4-methylenedioxyphenylethylamine (VIII) with N-carbobenzoxy-3-methoxy-4-hydroxyphenylethylamine (IX) through an Ullman condensation catalysed by CuO, followed by elimination of the formyl group with HCl in methanol. Compound (VIII) is prepared as follows: 3,4-dihydroxy-5-bromobenzaldehyde (X) is methylenated with methylene bromide (A) and CuO in DMF giving 3,4-methylenedioxy-5-bromobenzaldehyde (XI), which is condensed with nitromethane (B) in acetic acid containing ammonium acetate affording 3,4-methylenedioxy-5-bromo-beta-nitrostyrene (XII). The reduction of (XII) under Clemensen conditions yields 3,4-methylenedioxy-5-bromophenylethylamine (XIII), which is finally formylated with formic acid in decalin. Compound (IX) is prepared as follows: 3-methoxy-4-hydroxy-beta-nitrostyrene (XIV) is treated with ethyl chloroformate (C) in pyridine yielding the corresponding ethoxycarbonyl derivative (XV), which is reduced under Clemensen conditions to 3-methoxy-4-ethoxycarbonyloxyphenylethylamine (XVI). Finally, this compound is treated first with benzyloxycarbonyl chloride and then with aqueous NaHCO3.