合成路线1

The intermediate tricyclic carbaldehyde has been obtained by two different methods: 1. The dicarboxylic ester (I) is methylated with Me-I and Ag2O in dioxane to give the dimethoxy compound (II), which is reduced with LiAlH4 in THF to obtain the dicarbinol (III). Monoesterification of (III) with benzoyl chloride and pyridine in dichloromethane yields the monobenzoate (IV), which is oxidized with DMP to afford the carbaldehyde (V). The Grignard reaction of (V) with methylmagnesium bromide and MeLi in THF provides the diol (VI), which is oxidized with oxalyl chloride to furnish the desired intermediate carbaldehyde (VII). 2. The reaction of the tricyclic ketone (VIII) with phosphonium bromide (IX) by means of tBu-OK in THF gives methylene derivative (X), which by hydroboration with BH3 and H2O2 in THF yields the carbinol (XI). The oxidation of (XI) with DPP affords the carbaldehyde (XII), which is condensed with the 1-aminopyrrolidine (XIII) to afford the hydrazone (XIV). The acylation of (XIV) with acetyl chloride and LDA in THF provides the acetyl derivative (XV), which is finally treated with oxalic acid go give the desired intermediate carbaldehyde (VII).