Preparation of Enantiomerically Pure (S)-(-)-1-(1'-naphthyl)-ethanol by the Fungus Alternaria alternata.

(S)-(-)-1-(1'-napthyl)-ethanol (S-NE) is an important intermediate for the preparation of mevinic acid analogs, which is used for the treatment of hyperlipidemia. The objectives of the study were to isolate a microorganism that could effectively reduce 1-acetonaphthone (1-ACN) to S-NE, to determine the influence that the physicochemical parameters would have on the reduction by the isolated microorganism, and to attempt large-scale studies with the microorganism. Over the years fungi have been considered a promising biocatalyst and it has been presumed that many fungal species have not been isolated and therefore the current study focused on possible isolation of these microorganisms. A total of 72 fungal isolates were screened for their ability to reduce 1-ACN to its corresponding alcohol. The isolate, EBK-62, identified as Alternaria alternata, was found to be the most successful at reducing the ketone to the corresponding alcohol in the submerged culture. The reaction conditions were systematically optimized for the reducing agent A. alternata EBK-62, which showed high stereospecificity and good conversion for the reduction. The preparative scale study was carried out in a 2 L bioreactor and a total of 4.9 g of S-NE in optically pure form (>99% enantiomeric excess) was produced in 48 h. Chirality 28:669-673, 2016. © 2016 Wiley Periodicals, Inc.

Synthesis of chiral sulfoximines derived from 3-aminoquinazolinones and their catalysis of enantioselective diethylzinc addition to aldehydes.

A series of sulfoxides were sulfoximinated using oxidative addition of 3-aminoquinazolinones by lead tetraacetate in the presence of hexamethyldisilazane. They were applied for the first time in catalytic enantioselective addition to aromatic aldehydes with a product enantiopurity (ee) of 92% in the case of 2-methoxybenzaldehyde.

Production of (R)-1-phenylethanols through bioreduction of acetophenones by a new fungus isolate Trichothecium roseum.

A total of 120 fungal strains were isolated from soil samples and evaluated in the bioreduction of substituted acetophenones to the corresponding (R)-alcohols. Among these strains, isolate Trichothecium roseum EBK-18 was highly effective in the production of (R)-alcohols with excellent enantioselectivity (ee > 99%). Gram scale preparation of (R)-1-phenylethanol is reported.

Diastereoselective control through hydrogen bonding in the aziridination of the chiral allylic alcohols by acetoxyaminoquinazolinone.

A high diastereoselectivity (up to >99:1) is found for the aziridinations of chiral allylic alcohols with acetoxyaminoquinazolinone (Q-NHOAc). The selectivity is explained in terms of hydrogen bonding between the hydroxy functionality of the allylic alcohol and the remote carbonyl group of the quinazolinone.

Antimicrobial and antioxidant activity of the essential oil and methanol extract of Nepeta cataria.

Catnip (Nepeta cataria) is an important medicinal herb belonging to the mint family, Lamiaceae. In this study, the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract from Nepeta cataria, and its essential oil composition were investigated. The essential oil, which has 4aalpha,7alpha,7abeta-nepetalactone (70.4%), 4aalpha,7alpha,7abeta-nepetalactone (6.0%), thymol (2.3%), and 4aalpha,7alpha, 7abeta3-nepetalactone (2.5%), as main components, exhibited activity against eleven bacteria, and twelve fungi and a yeast, C. albicans; with Minimum Inhibitory Concentrations (MIC) values ranging from 12.50 to 250 microl/ml; the methanol extract showed weaker activity. The samples were also subjected to a screening for their possible antioxidant activities by using 2.2-diphenyl-1-picrylhydrazyl (DPPH) and beta-carotene/linoleic acid assays. In DPPH assay, the extract showed slight antioxidant activity whereas the essential oil remained inactive. In the latter case, both the extract and the essential oil exerted weak activity having inhibiton ratios of linoleic acid oxidation at 16.4% and 27.0%, respectively. The weak antioxidative nature of the extract could be attributed to the low phenolic content, estimated as gallic acid equivalent at 22.6 +/- 2.07 microg/ml or 2.26%. In both systems, antioxidant capacity of BHT was determined in parallel experiments.

Singlet oxygen generation from [bis(trifluoroacetoxy)iodo]benzene and hydrogen peroxide.

Decomposition of hydrogen peroxide with a hypervalent iodine compound was examined. The results indicate that treatment of a hypervalent iodine compound with hydrogen peroxide produces singlet molecular oxygen ((1)O(2)). Convergent evidence for the production of singlet molecular oxygen ((1)O(2)) by decomposition of hydrogen peroxide with a hypervalent iodine compound comes from chemical trapping experiments and the specific chemiluminescence detection of (1)O(2) at 1270 nm. Substantial evidence demonstrates that hydroperoxyl radical produced from hydrogen peroxide with hypervalent iodine reacts via a tetraoxidane intermediate, decomposing to give singlet molecular oxygen.

Effect of additives on chemoselectivity and diastereoselectivity in the catalytic epoxidation of chiral allylic alcohols with hydrogen peroxide and binuclear manganese complexes.

The catalytic oxidations of chiral allylic alcohols 2 by manganese complexes of the cyclic triamine 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) 1 and hydrogen peroxide as oxygen donor in the presence of co-catalyst are investigated to understand the factors that affect the catalyst selectivity. Chemoselectivity and diastereoselectivity of catalyst 1 are significantly affected by the structure of the allylic alcohol and the nature and amount of co-catalyst. More pronounced is the influence of the amount of added molar equivalents of H(2)O(2) (20-110 mol % with respect to the substrate). Our present results reflect the complex redox chemistry of the Mn catalyst 1/H(2)O(2)/co-catalyst system in the early phase of the alkene oxidation.

Chemical composition and antimicrobial and antioxidant activities of the essential oil and methanol extract of Hippomarathrum microcarpum (Bieb.) from Turkey.

Hippomarathrum microcarpum grows wild in eastern Anatolia, Turkey, and is a plant utilized as food by people. In this study, the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract from H. microcarpum and its essential oil composition were investigated. The essential oil, which has bornyl acetate, caryophyllene oxide, and beta-caryophyllene as its main components, exhibited activity against eight bacteria, nine fungi, and a yeast, Candida albicans, with minimum inhibitory concentration values ranging from 62.50 to 125 muL/mL; the methanol extract showed weak activity. The antioxidant activity of these extracts was assessed by the beta-carotene bleaching test and the 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging test. The inhibition of linoleic acid oxidation was very weak for both extracts tested. The inhibition percentages were found to be 22.9 and 33.5% for methanol and essential oil, respectively, at the concentration of 2 g/L. The oil scavenged DPPH at higher concentrations (IC50 = 10.69 +/- 0.05 mg/mL), but the methanol extract exhibited no activity. The total phenolic content of the methanol extract was found to be 4.7 +/- 0.1%.

Screening of chemical composition and antifungal and antioxidant activities of the essential oils from three Turkish artemisia species.

The compositions of essential oils isolated from the aerial parts of Artemisia absinthium, Artemisia santonicum, and Artemisia spicigera by hydrodistillation were analyzed by GC-MS, and a total of 204 components were identified. The major components of these essential oils were camphor (34.9-1.4%), 1,8-cineole (9.5-1.5%), chamazulene (17.8-nd%), nuciferol propionate (5.1-nd%), nuciferol butanoate (8.2-nd%), caryophyllene oxide (4.3-1.7%), borneol (5.1-0.6%), alpha-terpineol (4.1-1.6%), spathulenol (3.7-1.3%), cubenol (4.2-0.1%), beta-eudesmol (7.2-0.6%), and terpinen-4-ol (3.5-1.2%). The antifungal activities of these essential oils were tested against 11 plant fungi and were compared with that of a commercial antifungal reagent, benomyl. The results showed that all of the oils have potent inhibitory effects at very broad spectrum against all of the tested fungi. Pure camphor and 1,8-cineole, which are the major components of the oils, were also tested for antifungal activity against the same fungal species. Unlike essential oils, these pure compounds were able to show antifungal activity against only some of the fungal species. In addition, the antioxidant and DPPH radical scavenging activities of the essential oils, camphor, and 1,8-cineole were determined in vitro. All of the studied essential oils showed antioxidant activity, but camphor and 1,8-cineole did not.