Chemistry of Acronycine VI. Proton NMR Spectral Assignments of Acronycine and Derivatives and the Formation of Isonoracronycine

Abstract

Proton NMR assignments for acronycine and a series of derivatives are reported based on extensive homonuclear decoupling and nOe experiments at high-field. The formation of isonoracronycine ( 3) from noracronycine ( 2) under acidic conditions is discussed.

Chemistry of Acronycine VIII. Selective Synthesis of Dimers and Trimers of Noracronycine and Related Compounds

“…When noracronycine (2) was treated with a mixture of 98% H2S04 and MeOH in the ratio 1:1, the yield of was about 40%, a tenfold increase compared with 98% H2S04. Catalytic hydrogenation of 3 afforded dihydro AB-1 (9) in almost quantitative yield (11). As reported previously (14), dihydro AB-1 (9) could also be produced, in about 40% yield, through a condensation-disproportionation reaction together with dihydro AB-3 (13), by treating a 1:10 mixture of AB-1 (3) and dihydronoracronycine (6) with methanolic HC1 under a N2 atmosphere at room temperature for 24 h.…”

“…int.) 616 (M+, 46), 601(16), 598 (15), 587 (12), 318 (10), 311 (15), 310(68), 309(26), 308(48), 307 (100), 306 (10), 292 (31), 280 (22), 278(26), 264 (12), 263 (13), 262(18), 254(19), and 236 (9).…”

“…Because of our interest in the development of acronycine (1) and/or its derivatives as antineoplastic agents, we have been investigating their chemical and spectroscopic properties (1,(9)(10)(11)(12)(13)(14)(15)). An area of particular interest has been the nature of the complex mixture formed when noracronycine (2) is treated with hot methanolic HC1 (11).…”

“…With these results in hand, we began to examine further the selective synthesis of other dimers of noracronycine (2) and related compounds. When the coupling of 2 and 6 was performed at room temperature, a 1:1 mixture of dihydro AB-1 (9) and dihydro was obtained, as well as unreacted 6 (11). However, if des-N-methyl acronycine (10) was used instead of 2, and a 1:10 mixture of 10 and 6 was refluxed in methanolic HC1 on a steam bath for 6 h, des-N-methyl-O-methyl dihydro was obtained.…”

Quinoline, quinazoline, and acridone alkaloids

“…This synthetic method has now been applied to a variety of hemiterpenoid quinoline alkaloids. Thus the 4-hydroxylated carboxylic acids (42) behave similarly, to give a mixture of the prenylated derivatives ( 43) and ( 45 form the isopropylfuroquinoline (52) ; the latter compound was also prepared by successive reactions of compound (48) with Nbromosuccinimide and formic acid.30 A new synthesis of the alkaloid lunacrine (51) resulted from catalytic reduction of the isopropylfuroquinoline (52) followed by the reaction of the product with methyl iodide and rearrangement of the resultant quaternary ammonium salt, using the method that was described previously. Grundon et ~1 .…”