Daunomycin is a new and very promising antitumor antibiotic. This communication reports the synthesis of (dl)-4-demethoxy-7-0-methyl daunomycinone as part of a scheme toward the totaI synthesis of daunomycin.La daunomycine est un antibiotique nouveau et prometteur contre les tumeurs. Cette communication relate la synthese du dl demethoxy-4 0-methyl-7 daunomycinone en tant qu'etape en vue de la synthese totale de Ia daunomycine.

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At room temperature the proton magnetic resonance spectrum of u,u-dichloro-2,4,6-tribromotoluene is ABX where the methine proton in the sidechain is X and is lying in the plane of the aromatic ring. At higher temperatures the ring proton spectrum, AB, broadens and eventually collapses to yield an AZX spectrum. From an analysis of the ring proton line shapes the barrier to rotation of the dichloromethyl group about the spZ-sp3 c a r b o n~a r b o n bond is obtained; AG* = 17.5 + 0.1 kcal/mole at 304 OK, AH* = 15.67 + 0.08 kcal/mole, AS* = -7 e.u., E , = 16.38 + 0.08 kcal/mole, log A = 11.78 k 0.23 where the least squares errors given should probably be multiplied by a factor of from 3 to 5 to take possible systematic errors into account. The barrier is about 2 kcal/mole higher than in u,u,2,4,6-pentachlorotoluene. The barrier to rotation arises from the conformation in which chlorine and bromine atoms are eclipsed.Canadian Journal of Chemistry, 48, 2839 (1970) IntroductionThe previous paper (1) in this series presented a detailed description of a proton magnetic resonance (p.m.r.) study of hindered rotation of the dichloromethyl group in cr,cr,2,4,6-pentachlorotoluene (PCT). A computer program based on a density matrix treatment of intramolecular proton exchange was developed and applied in the extraction of preexchange lifetimes from the temperature dependent ring proton spectrum of PCT. The present paper gives the results of a similar application to the ring proton spectrum of cr,cr-dichloro-2,4,6-tribromotoluene (DCTBT).

Optically active (-)-deacetyl anisomycin and theenantiomer (+)-deacetyl anisomycin were synthesized starting with (+)-2R 3R tartaric acid. The asymmetric centers of the tartaric acid correspond to the C-2 and C-3 asymmetric centers of anisomycin. N-Benzyl tartarimide (3) was attacked by the Grignard reagent of anisyl chloride followed by lithium aluminium hydride reduction to give two diols (7) and (8) separated by thin-layer chromatography. The diol (8) was debenzylated giving the natural (-)-deacetyl anisomycin. The diol (7) was converted into the epoxide (10) by selective acetylation of the C-4 hydroxy group followed by treatments with phosphorus pentachloride and sodium ethoxide. Opening of the epoxide ring of 10 in boiling acetic acid followed by basic hydrolysis gave (+)-N-benzyl deacetyl anisomycin (11) which was debenzylated to give (+)-deacetyl anisomycin.

Thiobinupharidine epimers possessing axial methyl groups at C-1 and C-1′ have been isolated from extracts of Nupharluteum. 13C chemical shift data for the methyl and ring carbons demonstrate that both methyl groups are axial in 1-epi-1′-epi-thiobinupharidine and that one of two methyls is axial in 1-epi- and in 1′-epi-thiobinupharidine.