合成路线1

3) The cyclization of benzoquinone (XXXVII) with 3-amino-4-methoxycrotonic acid methyl ester (XXXVIII) gives 5-hydroxy-2-(methoxymethyl)-1H-indole-3-carboxylic acid methyl ester (XXXIX), which is methylated to 5-methoxy-2-(methoxymethyl)-1-methylindole-3-carboxylic acid methyl ester (XL). The oxidation of (XL) with DDQ yields the corresponding aldehyde (XLI), which is submitted to a Horner-Emmonds condensation with 2-(dimethoxyphosphoryl)acetic acid ethyl ester (XLII) in a basic medium to afford the corresponding acrylic ester (XLIII). The nitration of (XLIII) gives 3-[5-methoxy-3-(methoxycarbonyl)-1-methyl-4-nitroindol-2-yl]acrylic acid ethyl ester (XLIV), the monoethyl ester analogue of compound (XVIII).The reduction of (XLIV) with Sn and 3N HCl in ethanol/water yields the corresponding 4-amino derivative (XLV), which is oxidized with Fremy's salt (nitrodisulfonic acid potassium salt) to afford 3-[5-methoxy-3-(methoxycarbonyl)-1-methyl-4,7-dioxo-4,7-dihydro-1H-indo l -2-yl]acrylic acid ethyl ester (XLVI). The reduction of (XLVI) with Na2S2O4 in CHCl3/ethanol/water gives the corresponding hydroquinone (XLVII), which is first reduced with DIBAL (diisobutylaluminum hydride) in toluene/dichloromethane and then oxidized again with FeCl3 to afford 3-(hydroxymethyl)-2-(3-hydroxy-1-propenyl)-5-methoxy-1-methyl-4,7-dihydro-1H-indole-4,7-dione (XXII). Finally, this compound is treated with aziridine (XXIII) in hot methanol.