HIGHLY EFFICIENT AND PRACTICAL SYNTHESES OF LAVENDAMYCIN METHYL-ESTERAND RELATED NOVEL QUINOLINDIONES

The novel 7-(N-formyl-, 7-(N-acetyl-, and 7-(N-isobutyrylamino)-2-meth ylquinoline-5,8-diones were synthesized in excellent overall yields in three steps via the nitration of the commercially available 8-hydroxy -2-methylquinoline followed by a reduction-acylation step and then oxi dation. Acid hydrolysis of 7-(N-acetylamino)-2-methylquinoline-5,8-dio ne (14a) afforded the novel 7-aminoquinoline-5,8-dione 7 in excellent yields. Due to our efficient preparation of dione 14a, we now report a short and practical method for the total synthesis of the potent anti tumor agent lavendamycin methyl ester (1b) with an excellent overall y ield.