Shigeo Tanimoto

The bovine serum albumin–2-phenylpropane-1,2-diolatodioxo-somium(VI) complex as an enantioselective catalyst for cis-hydroxylation of alkenes

The 1:1 complex between an osmate ester and bovine serum albumin was found to be effective as an enantioselective catalyst in the cis-hydroxylation of alkenes, affording diols in up to 68% e.e. and turnover of the catalyst with t-butyl hydroperoxide.

Selective synthesis of heterocyclic compounds through the intramolecular substitution of phenylselenonyl group by nitrogen or carbonyl oxygen in amides

Abstract Nitrogen heterocycles were produced by the oxidation of N-[ω-(phenylseleno)alkyl]-p-toluenesulfonamides through the intromolecular substitution of the resultant phenylselenonyl group by the nitrogen atom. By the oxidation of the corresponding benzamides, on the other hand, cyclization by nitrogen or carbonyl oxygen proceeded depending on the number of carbon atoms between the nucleophile (amide) and the leaving group (selenonyl group).

Stereoselective oxidation of aromatic sulfides and sulfoxides in the binding domain of bovine serum albumin

Abstract The oxidation of aromatic sulfides with achiral oxidizing agents, e.g., sodium metaperiodate (NaIO 4 ) and hydrogen peroxide (H 2 O 2 ) in the binding domain of bovine serum albumin (BSA), furnished a strong asymmetric bias (max 81%) of the product sulfoxides in fairly high chemical yields. The kinetic resolution of racemic aromatic sulfoxides was also carried out in the chiral binding domain, and the remaining unchanged sulfoxides showed optical purities ranging over 1–33% at ca. 50% completion of oxidation. The combination of the two stereoselective oxidations above mentioned produced several optically active sulfoxides of >90% optical purity in ca. 50% chemical yield. The present method constitutes a successful biomimetic approach to achieving stereoselectivities as high as obtained by sulfur-oxidizing microorganisms.

A hydrolytic enzymelike behavior or bovine serum albumin in hydrolysis of p-nitrophenyl esters

Abstract The investigation of hydrolysis of p-nitrophenyl acetate (NPA) catalyzed by bovine serum albumin (BSA) proved that the initial rate in the steady state folows a Michaelis-Menten equation. In the use of D- and L-p-nitrophenyl α-methoxyphenlacetates (D- and L-NPMAs) as an enantiomeric ester, the L-enantiomer is hydrolyzed about three times faster than the D-enantiomer, mainly due to stronger binding of the former enantiomer by BSA.

A novel synthesis of half-protected 1,3-dicarbonyl compounds

Abstract It has been found that the reaction of enol silyl ethers with 2-ethoxy-1,3-dithiolane proceeds smoothly in the presence of zinc chloride catalyst to afford half-protected 1,3-dicarbony1 compounds in moderately good yields.

Asymmetric reduction of alkyl aryl ketones in the binding domain of bovine serum albumin

Abstract The asymmetric reduction of alkyl aryl ketones with sodium borohydride (NaBH 4 ) or sodium cyanoborohydride (NaBH 3 CN) in the presence of bovine serum albumin (BSA) was studied. The asymmetric induction in the product alcohols was largely dependent on the BSA concentration and the pH value of the buffer solution. The maximum optical yields obtained ranged over 14–78%, varying with the alkyl and aryl substituents, using ca. 1 3 molar eq of BSA to the ketone and at pH > 9. With two exceptions, the predominant enantiomer had the R configuration in 13 ketones investigated.

A Convenient Preparation of p-Chloromethyl-Styrene and its Reactions

Abstract In the present communication we would like to describe a novel method for the preparation of p-chloromethylstyrene and some reactions of this compound.

Generation of 1,2-ethanebis(trithiocarbonic acid) dianion from 2,2′-[1,2-ethanediylbis(thio)]- bis-1,3-dithiolane and its reaction with alkyl halides

Abstract Generation of 1,2-ethanbis(trithiocarbonic acid) dianion from 2,2′-[1,2-ethanediylbis (thio)]bis-1,3-dithiolane and its reaction with alkyl halldes were investigated.

The reaction of five-membered cyclic trithiocarbonates with n-butyllithium

Abstract It was found that the reaction of five-membered cyclic trithiocarbonates with n -butyllithium in tetrahydrofuran is applicable to the preparation of unsymnetrical linear trithiocarbonates and further to the interconversion of cis - and trans -olefins.

Preparation of optically active aromatic sulphoxides of high optical purity by the direct oxidation of the sulphides in the presence of bovine serum albumin

Aromatic sulphides were oxidized with sodium metaperiodate in the presence of bovine serum albumin to give the corresponding sulphoxides of high optical purity (81% max.) in good chemical yields.