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

Abstract

Improved synthetic procedures for the formation of a number of dimeric derivatives of noracronycine (2) are described based on acid-catalyzed reactions in methanolic HCl or methanolic H2SO4. A detailed analysis of their high-field proton nmr spectral characteristics is presented. The synthesis and structure determination of a new trimer of noracronycine (2) possessing the linear-angular-angular structure (15) is described.

Chemistry of Acronycine, XI. Rearrangement of Dihydronoracronycine to Dihydroisonoracronycine-Mechanistic Studies

“…The combinerd CHC13 layers were washed with 5% NaHCG3 solution and H2G (each 50 ml), dried over anhydrous Na2SG4, and concentrated in vacuo to afford a brownish yellow powder (8.4 mg). Through preparative tic eluting with CHC13 as the solvent, deutero-dihydroisonoracronycine (12) was isolated as a yellow powder; ms mlz 319 (8%), 318 (35), 317 (84), 316 (19), 315 (8), 314 (8), 299(9), nmr (60 MHz, CDC13) 62.74 (bs, 2H, 4-CH2), 3.71 (3H, s, N-CH3), 6.25 (0.2 H, s, C12-H), 7.24 (IH, dtj= 1, 7 Hz, Cg-H), 7.40 (IH, ddj= 1.7 Hz, C10-H), 7.55 (IH, dt,7= 1.7 Hz, Cg-H), 8.44 (IH, ddj=2, 8 Hz, C7-H), and 15.08 (IH, s, 5-OH). (14).-A mixture of 13 and 14…”

“…It was therefore concluded that the geminal methyl moiety of the acronycine skeleton is necessary for rearrangement to the isoacronycine skeleton.3 Through these experiments there was established the possibility of an intermolecular rearrangement in the transformation of dihydronoracronycine (3) to dihydroisonoracronycine (4), which leads to disproportionation and the formation of dihydroisonoracronycine (3), 1,3-dihydroxy-10-methyl acridone (5), 9, and 11 (Scheme 1). The complex array of products formed through the /«/ermolecular reactions of noracronycine (2) have been described previously (1,(18)(19)(20)(21).…”