Optical Resolution of (±)-Metyrosine

A lipase gene (lip) and its activator gene (act) on a 2.9 kb BglII-EcoRI fragment from Pseudomonas sp. KWI-56 were cloned in Escherichia coli using pUC19 as a vector plasmid. From the sequencing results, the open reading frames of the lip and the act were found to contain 1092 and 1032 nucleotides, respectively. The act existed downstream of the lip with the same orientation. When the lip was expressed in E. coli using the lac promoter on the pUC plasmid vector, the lipase activity of E. coli carrying both the lip and the act was 200-fold greater than that carrying only the lip. This result suggested the act was important in the expression of the lip in E. coli.     

Enzymatic Deamination of (±)-2-Methyl- and (S)-2,2-Dimethyl-1-aminocyclopropane-1-carboxylic Acid

The effects of drinking deaerated water on serum biochemical values, and on the concentrations of short-chain fatty acids (SCFAs) derived from bacterial fermentation in the colon were examined in rats. Drinking deaearted water decreased the levels of serum alkaline phosphatase (SAP) and serum urea nitrogen (SUN), and increased the serum potassium (SK) and serum phosphorus (SP) levels. Although the concentration of propionic acid in the cecum was decreased by drinking deaerated water, the concentrations of isobutyric, valeric, and isovaleric acids in the cecum were increased.     

Preparation of (±)-2-(2,3-2H2)Jasmonic Acid and Its Methyl Ester,Methyl (±)-2-(2,3-2H2)Jasmonate

For use as the internal standards in a quantitative analysis of natural jasmonic acid (JA) and methyl jasmonate (JAMe) by gas chromatography-mass spectrometry-selected ion monitoring, (±)-2-(2,3–²H₂)JA and its methyl ester, (±)-2-(2,3–²H₂)JAMe, were efficiently prepared from 2-(2–pentyl)-2-cyclopentenone through catalytic semi-deuteriogenation of acetylenic intermediates with deuterium gas in pyridine.     

Synthesis of (±)-Homosarkomycin and (±)-Rosaprostol

(±)-Homosarkomycin (2) and (±)-rosaprostol (3) were synthesized from (±)-methyl 2-oxo-bicyclo[3.1.0]hexane-1-carboxylate (1) by using the nucleophilic ring opening reaction on the double-activated cyclopropane ring as the key step.     

Synthesis of (±)-Lamprolobine and (±)-Epilamprolobine

(±)-Lamprolobine, the (+)-enatiomer of which was isolated from the leaves of Lamprolobium fruticosum, and (±)-epilamprolobine were synthesized from δ-valerolactam.     

Microbial production of (R)-3-halolactic acid from (±)-3-halo-1,2-propanediol

Microbial oxidation of (±)-3-halo-1,2-propanediol was studied and it was found that several microorganisms accumulated (R)-3-halolactic acid. Geotrichum loubieri CBS 252.61 produced the most and gave optically pure (R)-3-chlorolactic acid and (R)-3-bromolactic acid from the corresponding diols.     

Resolution of (±)-trans-2-phenylcyclohexan-1-ol by lipases from Candida rugosa: effect of catalyst source and reaction conditions

Candida rugosa lipase resolved trans-2-phenylcyclohexan-1-ol. A commercial and a laboratory preparation were compared and better results were obtained with the latter (E >200). Both enzyme preparations were strongly dependent on the substrate concentration for their enantioselectivity. This effect could be due to the presence of an esterase activity unspecific for trans-2-phenylcyclohexan-1-ol. © Rapid Science Ltd. 1998     

Biotransformation of (±)-2-methylcyclohexanone by fungi

The biotransformation of 2-methylcyclohexanone (1) using 16 fungal strains and some mushroom cultures was investigated. Fusarium sp. was one of the effective biocatalysts for oxidoreduction of 2-methylcyclohexanone (1). cis-2-Methylcyclohexanol (2a) was isomerized to trans-2-methylcyclohexanol (2b) by Fusarium sp. In addition, the corresponding lactones 3 was obtained by Baeyer-Villiger oxidation using Fusarium sp. AP-2 (46%, 94% ee).     

Synthesis of ( ± )-Methyl Epijasmonate and ( ± )-Methyl Cucurbate

A novel synthesis of ( ± )-methyl epijasomonate (2) and the first synthesis of ( ± )-methyl cucurbate (4) were achieved starting from 2-allylcyclohexane-1,3-dione (8). The synthetic epimer 2 had a stronger jasmin flavor than the trans-isomer 1 with 95% purity.     

Individual and combined effect of (±)-α-hydrastine and (±)-β-hydrastine on spore germination of some fungi

(+/-)-alpha-Hydrastine and (+/-)-beta-hydrastine were isolated from Corydalis longipes; both exhibited considerable efficacy against spore germination of some saprophytic and phytopathogenic fungi. While (+/-)-alpha-hydrastine was effective against most of the fungi, Helminthosporium echinoclova was least affected even at the highest dose (150 ppm). (+/-)-beta-Hydrastine was equally effective against several fungi. Mixture of both compounds was more effective than each one individually. Helminthosporium species were again the most resistant toward the mixture. The effect of both alkaloids independently on germination and development of E. pisi conidia on excised pea leaves was also shown. After pre-inoculation with (+/-)-alpha-hydrastine, the effect was more pronounced than the addition post-inoculation; maximum inhibition occurred at 200 ppm. (+/-)-beta-Hydrastine also reduced germination of conidia but was less effective than (+/-)-alpha-hydrastine. The number of primary and secondary branches of conidia and number of appressoria were not affected significantly by either compound.     

Syntheses of (±)-Epoformin (Desoxyepoxydon) and (±)-Epiepoformin (Desoxyepiepoxydon)

Boron is an essential nutrient for plants, but it is toxic in excess. Transgenic rice plants expressing an Arabidopsis thaliana borate efflux transporter gene, AtBOR4, at a low level exhibited increased tolerance to excess boron. Those lines with high levels of expression exhibited reduced growth. These findings suggest a potential of the borate transporter BOR4 for the generation of high-boron tolerant rice.     

An Efficient Synthetic Method for (±)-Malyngolide and Its Optical Resolution

A convenient synthetic method for (±)-malyngolide (1), an antibiotic from the marine bluegreen alga Lyngbya majuscula GOMONT, is described. The compound (±)-1 was synthesized from 2-methylglutaric anhydride (starting material) in four steps, involving the TBHP-based osmium-catalyzed procedure for vicinal dihydroxylation of the methylene unit in unsaturated carboxylic acid as the key step. The optical resolution of (±)-l was accomplished by HPLC, in which diastereomeric (+)-2-(4-chlorophenyl)isovaleric acid [(+)-CPIA] esters of (±)-l derived from (+)-CPIA-C1 could be easily separated, and subsequent hydrolysis of each ester gave the enantiomeri-cally pure (?)-l and (+)-l, respectively. A synthetic method for α-methylene malyngolide, which is to be expected for biological activity, is also described.     

Selective biocatalytic aminolysis of (±)-epichlorohydrin: synthesis and ICAM-1 inhibitory activity of (S)-(+)-3-arylamino-1-chloropropan-2-ols

Regio- and enantioselective synthesis of (S)-(+)-3-arylamino-1-chloropropan-2-ols has been achieved by the epoxide ring opening of (±)-epichlorohydrin with different aromatic amines in the presence of Candida rugosa lipase. Activities of seven model (S)-(+)-3-arylamino-1-chloropropan-2-ols, out of 10 compounds synthesized, have been evaluated for the inhibition of tumor necrosis factor-α TNF-α) induced expression of intercellular adhesion molecule-1 (ICAM-1), which is one of the factors responsible for the modulation of inflammation in biological systems; (S)-(+)-1-chloro-3-(2'-chlorophenylamino)-propan-2-ol has been found to exhibit highest activity, that is, 86% inhibition of TNF-α induced expression of ICAM-1 at a concentration of 40 μg/ml.     

Lipase-Catalyzed Kinetic Resolution of (±)-cis-Flavan-4-ol and Its Acetate: Synthesis of Chiral 3-Hydroxyflavanones

Lipase-catalyzed kinetic resolution of (±)-cis-flavan-4-ol and its acetate led to enantiomerically enriched flavan-4-ol and its acetate. These chiral compounds were converted to (2R, 3R)- and (2S, 3S)-3-hydroxyflavanones.     

Asymmetric Hydrolysis of (±)-1-Acetoxy-2,3-dichloropropane with Enzymes and Microorganisms

Enzymes and microorganisms were screened for the enantioselective hydrolysis of (±)-1-acetoxy-2,3-dichloropropane (1) which is convertible to epichlorohydrin. Pancreatin and steapsin from hog pancreas were found to hydrolyze (±)-1 asymmetrically to give (S)-1 of 90% enantiomeric excess (e.e.). From (S)-1 was synthesized the optically pure (S)-isomer of propranolol[1-isopropylamino-3-(1-naphthoxy)-2-propanol], one of the typical β-adrenergic blocking agents.     

Total synthesis of (±)-elegansidiol, (±)-farnesiferol B,and (±)-farnesiferol D

The racemic total synthesis of elegansidiol, farnesiferol B, and farnesiferol D has been obtained following a Diels–Alder approach. Gillman addition, cross metathesis reaction are the other key steps involved in the target synthesis.