(+)-Thiomicamine, an industrial waste product, has been transformed into (–)-(4S,5S)- 4-hydroxymethyl-5-p-methylthiophenylxazolidin-2-one, a sulfur analog of isocytoxazone, the regioisomer of the potent cytokine modulator, (–)-cytoxazone.
Oxidation of methyl p-tolyl sulfide with hydrogen peroxide catalyzed by VO(acac)2 - Schiff base 12 complex afforded R-(+)-methyl p-tolyl sulfoxide in high yield and with 43% e.e. Recrystallization of the product from ethyl ether/hexane resulted in the sulfoxide enantiomerically enriched up to 99.7% [m.p. 71-74_C; [_]D +144.6_ (c = 2.02, acetone)].
Thiazolino[2,3-a]isoquinolinones have been oxidized to the corresponding S-oxides and their 10b-methyl derivatives desulfurized with Raney nickel to give (š) N-acyl salsolidine. Base-catalyzed hydrolysis of the N-acetyl derivative afforded (š)-salsolidine. C-Methylation reactions of the title heterocyclic system have been investigated throughly. Stereochemistry ofthe synthesized compounds nas been established.
The first total synthesis of enantiomerically enriched (+)- and (-)-corydalisol (1) has been performed by addition of lithiated optically pure 1,3-dithiane 3b to hydrastinine chloride (2a), followed by desulfurization, separation of diastereomers and reduction with lithium aluminum hydride.
The crystal structure of the title solvate has been determined by X-ray diffraction with R=0.065. The 1,3-dithiane ring presents a chair conformation, the substituents at C(2), C(4) and C(5) are all in equatorial positions and the molecular ratio of the solvate is 1:1.
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