合成路线1

This compound has been obtained by two related ways: 1) The Grignard reaction of 5,8-dimethylnaphthalene-2-carbaldehyde (I) with vinylmagnesium bromide in ether/THF gives the expected carbinol (II), which is oxidized with MnO2 in dichloromethane yielding the propenone (III). The condensation of (III) with 4-formylbenzoic acid methyl ester (IV) by means of 3-benzyl-5-(hydroxymethyl)-4-methylthiazolium chloride (BHMT) in refluxing ethanol affords the 1,4-butanedione (V), which is cyclized with ammonium acetate in refluxing methanol to give the substituted pyrrole (VI). Finally, the ester group of (V) is hydrolyzed with NaOH in refluxing ethanol/water. 2) 1,4-Butanedione (V) can also be obtained by condensation of 5,8-dimethylnaphthalene-2-carbaldehyde (I) with 4-acryloylbenzoic acid methyl ester (VII) by means of BHMT in hot DMF.