Yoshinobu Naoshima

Immobilization of lipase on a new inorganic ceramics support, toyonite, and the reactivity and enantioselectivity of the immobilized lipase

A porous ceramics support, Toyonite 200-M (TN-M), for the immobilization of lipases was prepared hydrothermally from the minerals of kaolinite. Compared with some other commercial solid supports, the TN-M one exhibited better stability and higher selectivity for lipase proteins, and lipase PS (Pseudomonas cepacia) immobilized on the ceramics support showed higher reactivity for organic substrates than the free crude enzyme.

Enantioselectivity of Candida antarctica lipase for some synthetic substrates including aliphatic secondary alcohols

Abstract Candida antarctica lipase (Novozym 435) showed good to high enantioselectivity in the acylation of aliphatic and aromatic secondary alcohols ( E = 38−166), and higher enantioselectivity in the hydrolysis of their corresponding acetates than other lipases tested, including lipases AY and MY ( Candida sp.) and lipases PS, AK and LIP ( Pseudomonas sp.).

Biotransformation of aromatic ketones with cell cultures of carrot, tobacco andGardenia

Abstract Immobilized cells of Daucus carota enantioselectively transformed aromatic ketones such as acetophenone and propiophenone, into the corresponding ( S )-alcohols with an optical purity of 89–99% ee in a chemical yield of 54–70%. Immobilized Gardenia jasminoides cells yielded the ( R )-alcohols with a 63–91% ee.

Biotransformation of acetophenone with immobilized cells of carrot, tobacco and Gardenia

Abstract Immobilized cells of Daucus carota transformed acetophenone into ( S )-α-phenethyl alcohol by a stereoselective reduction pathway. Immobilized cells of Nicotiana tabacum also transformed the same substrate into the ( S )-alcohol, but neither stereoselective reduction nor stereoselective oxidation was observed in the biotransformation process. ( R )- and ( S )-α-phenethyl alcohol of a high enantiomeric purity of > 99% ee can be prepared by the biotransformation of acetophenone with immobilized cells of Gardenia jasminoides and Daucus carota .

The mechanistic pathway of the biotransformation of acetophenone by immobilized cell cultures of Gardenia

Abstract Immobilized cells of Gardenia jasminoides enantioselectively transformed acetophenone into the corresponding ( R )-alcohol by a two-step pathway involving initial reduction of the aromatic ketone to produce a mixture of ( R )- and ( S )-α-phenethyl alcohol followed by stereoselective oxidation of the ( S )-aromatic alcohol to produce acetophenone.

Synthesis of racemate and enantiomers of 15-methyltritriacontane, sex-stimulant pheromone of stable flyStomoxys calcitrans L.

The synthesis of the racemate and two enantiomers of 15-methyltritriacontane (1), an active component of the sex-stimulant pheromone ofStomoxys calcitrans L., is described. Racemic 15-methyltritriacontane was synthesized in four steps from 1-hexadecene with a 72% overall yield. Both theR- andS-enantiomers were synthesized in eight steps, respectively, starting from optically pure (R)-(+)-pulegone.

BIOCATALYTIC PREPARATION OF CHIRAL ALCOHOLS BY ENANTIOSELECTIVE REDUCTION WITH IMMOBILIZED CELLS OF CARROT

The ability of immobilized cells of Daucus carota to reduce enantioselectively organic foreign substrates has been examined. The immobilized plant cells reduced, with excellent enantioselectivity, prochiral ketone substrates such as keto esters, aromatic ketones and heterocyclic aromatic ketones, leading to the corresponding chiral secondary alcohols with an enantiomeric purity of 52–99% ee in a chemical yield of 30–63%.

Synthesis of chiral alcohol and ester pheromones through enzyme-catalysed hydrolysis using Pseudomonas fluorescens lipase: preparation of (2R,6S,10S)-6,10–14-Trimethylpentadecan-2-ol and the propionate of (2R,8R)-8-methyldecan-2-ol

(2R,6S,10S)-6,10,14-Trimethylpentadecan-2-ol [(2R,6S,10S)-15], one of the stereoisomers of the sex pheromone of Corcyra cephalonica Stainton, was synthesized in highly optically pure form by the hydrolysis of the 2,2,2-trichloroethyl carbonate of (2RS,6S,10S)-6,10,14-trimethylpentadecan-2-ol [(2RS,6S,10S)-15a] with Pseudomonas fluorescens lipase. The same method led to stereochemically pure (2R,8R)-8-methyldecan-2-yl propionate [(2R,8R)-24], which is a component of the sex pheromone of Diabrotica species.

Asymmetric bioreduction of keto esters by immobilized baker's yeast entrapped in calcium alginate beads in both water and organic/water solvent systems.

Immobilized bakers yeast entrapped in calcium alginate beads, ca 1.5 mm diameter, was used more than 10 times in water and reduced ethyl 3-oxobutanoate and ethyl benzoylformate to the corresponding chiral hydroxy esters in good chemical yields and in high enantioselectivities. The biocatalyst was also successfully used in organic/water solvent systems such as hexane/water and acetonitrile/water, and in other systems, particularly in hexane, converted keto esters into their individual chiral hydroxy esters.

Enzymatic preparation of enantiomerically pure alkan-2- and -3-ols by lipase-catalysed hydrolysis with Pseudomonas cepacia in the presence of organic media

Pseudomonas cepacia lipase-catalysed hydrolysis of the acetates of racemic alkan-2- and -3-ols was carried out in the presence of organic media. Good to high enantioselectivity was observed in an acetone–water solvent system, the system leading to (R)-alcohols of 80–96% ee. Enantioselectivity can be affected by the presence of the double bond in the unsaturated acetate prepared from an alkenol. The increased enantioselectivity observed for an acetone–water reaction system was utilized in the synthesis of optically active natural products possessing alkan-2-ol skeletons, such as (2R,6R,10R)-6,10,14-trimethylpentadecan-2-ol, the natural form of the sex pheromone of Corcyra cephalonica, and (R)-sulcatol, an aggregation pheromone of ambrosia beetles.