- Process for preparing (S)- alpha-cyano-3-phenoxybenzyl-(S)-2-(4-chlorophenyl)-isovalerate
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The present invention relates to an environmentally benign process for the preparation of (S)-α-cyano-3-phenoxybenzyl-(S)-2-(4-chlorophenyl)isovalerate from its diastereomeric mixture (RS)-α-cyano-3-phenoxybenzyl-(S)-2-(4-chlorophenyl) isovalerate.
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Page/Page column 16; 17; 19-21; 24; 25
(2008/06/13)
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- A new phase transfer catalyst and its applications in organic transformations
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A new quaternary ammonium bromide salt has been used for the first time in phase transfer catalysis (PTC) reactions such as oxidation of alcohols to carbonyl compounds, alkylation and esterification reactions. Improved yields and reduced reaction times have been achieved by this procedure.
- Reddy, Ch. Venkateshwar,Mahesh,Raju,Reddy, V.V. Narayana
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p. 2797 - 2802
(2007/10/03)
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- 'Gelozymes' in organic synthesis. Part 2: Candida rugosa lipase mediated synthesis of enantiomerically pure (S)-cyano(3-phenoxyphenyl)methyl butyrate
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Significant changes in enantioselectivity (E) have been observed when the butanoate ester of (±)-1-hydroxy-1-(3-phenoxyphenyl)acetonitrile was subjected to hydrolysis in acetate buffer (pH 4.5, E = 6.4) and alcoholysis with 1-butanol in hexane catalysed by Candida rugosa lipase (E = 45). Enantiomerically pure (S)-butanoate ester so obtained (e.e. 98.4%) was converted to the corresponding (S)-cyanohydrin using Pseudomonas cepacia (Amano Ps) gelozyme. This strategy overcomes the problem of separation of the unwanted (R)-ester from the (S)-cyanohydrin.
- Fadnavis, Nitin W.,Babu, Ravi Luke,Sheelu, Gurrala,Deshpande, Ashlesha
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p. 1695 - 1699
(2007/10/03)
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- Development of an immunoassay for the pyrethroid insecticide esfenvalerate
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A competitive enzyme-linked immunosorbent assay was developed for the detection of the pyrethroid insecticide esfenvalerate. Two haptens containing amine or propanoic acid groups on the terminal aromatic ring of the fenvalerate molecule were synthesized and coupled to carrier proteins as immunogens. Five antisera were produced and screened against eight different coating antigens. The assay that had the least interference and was the most sensitive for esfenvalerate was optimized and characterized. The I50 for esfenvalerate was 30 ± 6.2 μg/L, and the lower detection limit (LDL) was 3.0 2+ 1.8 μg/L. The assay was very selective. Other pyrethroid analogues and esfenvalerate metabolites tested did not cross-react significantly in this assay. To increase the sensitivity of the overall method, a C18 sorbent-based solid-phase extraction (SPE) was used for water matrix. With this SPE step, the LDL of the overall method for esfenvalerate was 0.1 μg/L in water samples.
- Shan, Guomin,Stoutamire, Donald W.,Wengatz, Ingrid,Gee, Shirley J.,Hammock, Bruce D.
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p. 2145 - 2155
(2007/10/03)
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- Halogen alkenyl azolyl microbicides
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Novel halogenoalkenyl-azolyl derivatives of the formula STR1 in which R1 represents optionally substituted alkyl, optionally substituted alkenyl, optionally substituted cycloalkyl, optionally substituted aryl or represents optionally substituted heteroaryl, R2 represents alkyl, halogenoalkyl, 1-hydroxyalkyl, 2-hydroxyalkyl, 1-hydroxyhalogenalkyl, 1-alkenyl or 2-alkenyl, X1 represents fluorine, chlorine, bromine or iodine, X2 represents fluorine, chlorine, bromine or iodine, and Y represents nitrogen or a CH group, and addition products thereof with acids or metal salts are very active as microbicides in plant protection and in the protection of materials.
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- Pesticidal composition containing a microencapsulated organo-phosphorus or carbamate in a pyrethroid dispersion
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An insecticidal and/or acaricidal and/or nematicidal composition having a rapid efficacy and residual activity which comprises a mixture of a poorly water-soluble organophosphorus insecticide and/or acaricide and/or nematicide and/or a poorly water-soluble carbamate insecticide and/or acaricide which have been microencapsulated in water-insoluble polymer coatings with a dispersing agent used in forming a microcapsule part, with a poorly water-soluble pyrethroid insecticide and/or acaricide emulsified or suspended in water with the above-mentioned dispersing agent used in forming a flowable part.
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- One-Pot Synthesis of Optically Active Cyanohydrin Acetates from Aldehydes via Lipase-Catalyzed Kinetic Resolution Coupled with in Situ Formation and Racemization of Cyanohydrins
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A novel one-pot synthesis of optically active cyanohydrin acetates from aldehydes has been accomplished by lipase-catalyzed kinetic resolution coupled with in situ formation and racemization of cyanohydrins in an organic solvent.Racemic cyanohydrins 2, generated from aldehydes 1 and acetone cyanohydrin in diisopropyl ether under the catalysis of basic anion-exchange resin (OH- form), were acetylated stereoselectively by a lipase from Pseudomonas cepacia (Amano) with isopropenyl acetate as an acylating reagent.The (S)-isomer of 2 was preferentially acetylated by the lipase, while the unreacted (R)-isomer was continuously racemized through reversible transhydrocyanation catalyzed by the resin.These processes thus enabled one stage conversion of various aldehydes 1a-n into the corresponding (S)-cyanohydrin acetates 3a-n with up to 94 percent ee in 63-100 percent conversion yields.The racemization of the optically active cyanohydrin 2e by Amberlite IRA-904 (OH- form) was found to be much faster then the enzymatic acetylation, confirming the effective second-order asymmetric transformation.Enzymatic deacetylation of (S)-cyanohydrin acetates in an organic solvent and the synthesis of optically active pyrethroids are also described.
- Inagaki, Minoru,Hiratake, Jun,Nishioka, Takaaki,Oda, Jun'ichi
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p. 5643 - 5649
(2007/10/02)
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- Enantioselective Hydrolysis of α-Cyano-3-phenoxybenzyl Acetate with Arthrobacter Lipase
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Lipase-catalyzed enantioselective hydrolysis of the acetic ester of racemic α-cyano-3-phenoxybenzyl alcohol (CPBA) was examined to prepare (S)-CPBA.Most of the lipases tested hydrolyzed (S)-CPBA acetate preferentially, while Candida cylindracea lipase favored (R)-CPBA acetate.Enantioselective hydrolysis by Arthrobacter lipase gave optically pure (S)-CPBA in the reaction mixture of pH 4.0.The kinetic studies showed that (R)-CPBA acetate reacted as a competitive inhibitor.The Arthrobacter lipase solution in the water/oil biphasic reaction system could be usedrepeatedly.The lipase immobilized to resins had insufficient activity or low operational stability with the repeated batch reaction.The unhydrolyzed (R)-CPBA acetate was racemized by heating with triethylamine and could be reused as the substrate of enzymatic hydrolysis.A chemico-enzymatic process for the preparation of (S)-CPBA was developed based on these studies.
- Mitsuda, Satoshi,Yamamoto, Hidefumi,Umemura, Takeaki,Hirohara, Hideo,Nabeshima, Shigeyasu
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p. 2907 - 2912
(2007/10/02)
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- LIPASE-CATALYZED IRREVERSIBLE TRANSESTERIFICATION USING ENOL ESTERS: XAD-8 IMMOBILIZED LIPOPROTEIN LIPASE-CATALYZED RESOLUTION OF SECONDARY ALCOHOLS
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Procedures for preparation of XAD-8 immobilized lipoprotein lipase and the resolution of secondary alcohols of synthetic value in organic solvents using this immobilized enzyme have been developed.
- Hsu, Shu-Hui,Wu, Shihn-Sheng,Wang, Yi-Fong,Wong, Chi-Huey
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p. 6403 - 6406
(2007/10/02)
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- Process for preparation of an S-alpha-cyano S-alpha-isopropylphenylacetate
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A method of preparing an "A-alpha" single stereoisomer of an S-alpha-cyano-3-phenoxybenzyl S-alpha-isopropylphenylacetate by precipitation from a solution of an "alpha" diastereoisomer pair, S-alpha-cyano-3-phenoxybenzyl R,S-alpha-isopropylphenylacetate, and optional hydrolysis of the mother liquor and recycle of the components thereof. The phenylacetate "alpha" is prepared from the S-alpha-cyano-3-phenoxybenzyl alcohol and racemic alpha-isopropylphenylacetic acid or reactive derivative thereof.
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- Preparation of optically-active cyanomethyl esters
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Optically-active alpha-cyano esters are prepared by treating a non-symmetrical ketene with a racemic or an optically-active alpha-hydroxynitrile or with an aldehyde and cyanide ions in the presence of an optically-active amine catalyst.
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