Claudia Sanfilippo

Chloroperoxidase from Caldariomyces fumago is active in the presence of an ionic liquid as co-solvent

Chloroperoxidase from Caldariomyces fumago catalyses the oxidation of 1,2-dihydronaphthalene to (1R,2R)-(+)-dihydroxytetrahydronaphthalene in homogenous citrate buffer/ionic liquid mixtures, using t-butyl hydroperoxide as O<>2<> donor. It tolerates up to 30 (v/v) 1,3-dimethylimidazolium methylsulfate or 1-butyl-3-methylimidazolium methylsulfate. The enzyme activity in these ionic liquid co-solvent systems is retained for 24 h, but it falls to 3 h using non-ionic organic solvents such as t-BuOH or acetone.

Application of lipase catalysis in organic solvents for selective protection–deprotection of bioactive compounds

Abstract Lipases are useful catalysts to realise in non-conventional medium esterifications and alcoholysis of polyhydroxylated compounds with high level of regioselectivity. This paper describes some examples of regioprotection–deprotection of flavonoids and conduritols, realised in our laboratory, using Pseudomonas cepacia, Mucor miehei and Candida cylindracea (C. rugosa) lipases.

AN EFFICIENT ENZYMATIC PREPARATION OF (+)- AND (-)-CONDURITOL E, A CYCLITOL WITH C2 SYMMETRY

Abstract Lypozyme® IM (immobilised lipase from Mucor miehei) catalyses the enantiomeric alcoholysis of tetraacetylconduritol E (±)−2 to give enantiopure (1R,2R,3R,4R)-tetrahydroxycyclohex-5-ene, (−)−1, and the unreacted ester (1S,2S,3s,4S)-tetraacetyloxycyclohex-5-ene, (+)−2. The latter was transformed by basic hydrolysis into (+)−1 in high yield and 95% ee. Selective amination of partial ester (−)−3, obtained by short alcoholysis of (±)−2, furnished the previously unreported conduramine F-4, (−)−4.

Desymmetrization of cis-1,2-dihydroxycycloalkanes by stereoselective lipase mediated esterification

Abstract Meso -compounds 1,2-dihydroxycyclopentane ( 1 ), 1,2-dihydroxycyclohexane ( 2 ) and 1,2-dyhydroxycycloheptane ( 3 ) were desymmetrised by enantiotoposelective esterification with vinyl acetate in tert -butyl methyl ether catalysed by lipases from Pseudomonas cepacia, Candida antarctica (Novozym 435 ® ) and Mucor miehei (Lipozyme TM ® ). Both of the lipases from P. cepacia and M. miehei afforded the (1 S ,2 R )-acetate (+)- 1a and (1 R ,2 S )-acetates (−)- 2a and (+)- 3a in good enantiomeric excesses and chemical yield.

Catalytic behaviour of chloroperoxidase from Caldariomyces fumago in the oxidation of cyclic conjugated dienes

Chloroperoxidase from Caldariomyces fumago has been investigated as a catalyst for the oxidation of cyclic conjugated dienes. The nature of the substituents and the size of the carbocycle affect the enantioselectivity of the enzyme. An unexpected course of the CPO-catalyzed oxidation has been observed in the reaction of cis,cis-1,3-cyclooctadiene.

ENZYMATIC RESOLUTION OF ()-CONDURITOL-B, A KEY INTERMEDIATE FOR THE SYNTHESIS OF GLYCOSIDASE INHIBITORS

Abstract Lipases from porcine pancreas, Candida cylindracea and Mucor miehei (adsorbed on support, Lipozyme ® IM) catalysed in t -butylmethylether the alcoholysis of rac -conduritol-B peracetate, (±)- 1 , by n -butanol to give enantiopure (2 S ,3 S )-diacetoxy-(1 R ,4 R )-dihydroxycyclohex-5-ene, (−)- 3 , and (1 S ,2 R ,3 R ,4 S )-tetraacetoxy-cyclohex-5-ene, (+)- 1 . The enantioforms (+)- and (−)-conduritol-B, obtained after chemical hydrolysis of (−)- 3 and (+)- 1 , respectively, may be employed to prepare both the enantiomers of conduritol-B epoxide and cyclophellitol, powerful inhibitors of glycosidases.

Enzymatic desymmetrisation of conduritol D. preparation of homochiral intermediates for the synthesis of cyclitols and aminocyclitols

Abstract From meso -conduritol D tetraacetate four homochiral partial derivatives, namely (+)-(1 R ,2 R ,3 S ,4 S )-1-hydroxy-2,3,4-triacetoxy-5-cyclohexene, (−)-(1 R ,2 R ,3 S ,4 S )-2-hydroxy-1,3,4-triacetoxy-5-cyclohexene, (−)-(1 R ,2 R ,3 S ,4 S )-1-benzoyloxy-3,4-diacetoxy-2-hydroxy-5-cyclohexene and (+)-(1 R ,2 R ,3 S ,4 S )-3,4-diacetoxy-1,2-dihydroxy-5-cyclohexene, have been prepared through enzymatic reactions catalysed by one of the following lipases: from porcine pancreas, from Mucor miehei and from Candida cylindracea . These compounds are of potential utility in the synthesis of cyclitols and aminocyclitols. As an example, the preparation of the previously unreported (+)-conduramine C-4 is also reported.

Lipase-catalyzed regioselective protection of hydroxyl groups in aromatic dihydroxyaldehydes and ketones

Abstract Pseudomonas cepacia lipase catalyzes the acetylation in organic solvent of dihydroxyaldehydes and ketones using vinyl acetate as acyl donor. The method is completely regioselective and allows to obtain partially acetylated compounds different from those obtained by enzymic hydrolysis of polyacetoxy arylaldehydes and ketones.

Convenient access to both enantiomers of new azido- and aminoinositols via a chemoenzymatic route

Abstract 1,2-diacetylconduritol E, (±)-1, through complementary use of Mucor miehei (Lipozyme® IM) and Candida cylindracea lipases, affords (1S)-1,2-diacetylconduritol E, (+)-1, (1R)-1,2-diacetylconduritol E, (−)-1, (1S)-1,2,4-triacetylconduritol E, (+)-2, (1R)-1,2,4-triacetylconduritol E, (−)-2, with high enantiomeric excesses and chemical yields. Following two different methods, diester (+)-1 has been transformed into azidoinositol (−)-4 to give 1L-4-amino-4-deoxy-chiro-inositol, whereas triester (−)-2 furnished the azidoinositol (+)-13, easily converted into 1L-4-amino-4-deoxy-myo-inositol.

Enzymatic access to homochiral 1-acetoxy-2-hydroxycyclohexane-3,5-diene through lipase-assisted acetylation in organic solvent

Abstract Enantiotoposelective acetylation of cis -1,2-dihydroxycyclohexa-3,5-diene with vinyl acetate in tert -butyl methyl ether, promoted by immobilized lipase from Mucor miehei (Lipozyme ® IM), afforded (1 R ,2 S )-1-acetoxy-2-hydroxycyclohexa-3,5-diene in good chemical yield and high enantiomeric excess.