Antoni Siewiński

Enantioselective hydrolysis of esters and the oxidation of aromatic-aliphatic alcohols obtained therefrom by Spirodela oligorrhiza

Abstract Spirodela oligorrhiza hydrolyses benzyl acetate and enantiospecifically hydrolyses the acetates of racemic mixtures of 1-phenyl-ethanol, 1-(1-naphthyl)-ethanol, 1-(2-naphthyl)-ethanol, and 2-phenyl-butanol. The R alcohols are formed faster. Two of the resulting alcohols, 1-phenyl-ethanol and 1-(2-naphthyl)-ethanol, undergo an enantiospecific oxidation. Here, the S enantiomers react faster.

Biodegradation of hard coal and its organic extract by selected microorganisms

Abstract Biotransformation of powdered hard coal and its organic extract was achieved by means of Piptoporus betulinus, Nocardia rubra and Pseudomonas aureofaciens in aqueous medium. The process of depolymerization was evaluated on the basis of Chromatographic and spectral data. Gas chromatograms, high-performance size exclusion chromatograms and u.v., i.r. and 1 H n.m.r. spectra are discussed.

Transformation of isoprenoids by orchids in tissue culture

Abstract Tissue cultures of Epidendrum ochraceum; Cymbidium ‘Saint Pierre’ and Dendrobium phalaenopsis were found to transform some isoprenoids. The transformation of the oxygen functions at C-17 in androstane derivatives and the hydrolysis of (±)-menthyl acetate were investigated in some detail. The degree of hydrolysis of the latter was about 75–85%.

Enantiospecific hydrolysis of acetates of racemic monoterpenic alcohols by Spirodela oligorrhiza

Abstract Acetates of racemic menthol, borneol, trans -2-hydroxy- trans -dihydropinol, cis -2-hydroxy- trans -dihydropinol and trans -2-hydroxy- cis -dihydropinol undergo enantiospecific hydrolysis in cultures of Spirodela oligorrhiza . R Alcohols are formed faster than S . Absence of light inhibits hydrolysis of the first two acetates.

Transformation of androstane derivatives by Spirodela oligorrhiza

Abstract Spirodela oligorrhiza (duckweed) is capable of transforming some steroids of the androstane series. Hydrolysis of the acetates of testosterone and of 3β-hydroxyandrost-5-en-17-one by this species yielded the corresponding alcohols. Further transformation of testosterone and reduction of androst-4-ene-3,17-dione indicated the interconversions of the hydroxyl-ketone function on C-17 and reduction of the Δ 4 -double bond to the trans -A/B system. Only a trace amount of 3β-hydroxyandrost-5-en-17-one underwent further transformations.

Uncommon type of hydroxylation of 3-alkenylsubstituted derivatives of citronellol and citronellic acid by Spirodela punctata

Abstract Spirodela punctata transforms 3-(1′ E )-pentenylcitronellol and the ethyl ester of 3-(1′ E )-propenylcitronellic acid to derivatives with a hydroxy group on C-6 or C-7 and the double bond at C-7(8) and C-5(6), respectively.