Davis, Franklin A.; Clark, Charles; Kumar, Anil; Chen, Bang-Chi published the artcile< Asymmetric Synthesis of the AB Ring Segments of Daunomycin and 4-Demethoxydaunomycin>, COA of Formula: C10H15NO3S, the main research area is asym hydroxylation tetralone fragment daunomycin.
Asym. hydroxylation of the potassium enolate of β-keto ester I (R = H) with tetrahydro-9,9-dimethyl-8,8-dimethoxy-4H-4a,7-methanooxazirino[3,2-i][2,1]benzisothiazole 3,3-dioxide affords α-hydroxy β-keto ester (R)-(+)-I (R = OH) in >95% ee. The high ee’s are attributed to the fact that this enolate probably exists in one geometric form as a consequence of intramol. chelation. Reduction of the ketone in I (R = OH) with triethylsilane and conversion of the ester group into the Me ketone results in a highly efficient synthesis of the AB ring building block (R)-(-)-2-acetyl-5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthol (II, R1 = Me), a key intermediate in the asym. synthesis of the antitumor agent 4-demethoxydaunomycin. Selective deprotection of the 8-methoxy group in II (R1 = Me) with BBr3 gives II (R1 = H), important in the enantioselective synthesis of the clin. useful antitumor agent adriamycin. Attempts to prepare II more directly by asym. hydroxylation of the enolates of Me 5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthoate or the 8-benzyloxy analog of I (R = H) resulted in low ee’s, attributable to the formation of E/Z enolate mixtures and increased steric congestion in the transition state for hydroxylation.
Journal of Organic Chemistry published new progress about Hydroxylation, stereoselective. 104322-63-6 belongs to class isothiazole, and the molecular formula is C10H15NO3S, COA of Formula: C10H15NO3S.
Referemce:
Isothiazole – Wikipedia,
Isothiazole – ScienceDirect.com