- Resolution of (R, S)-ethyl-2-(4-hydroxyphenoxy) propanoate using lyophilized mycelium of Aspergillus oryzae WZ007
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The mycelium of Aspergillus oryzae WZ007 was successfully developed to kinetic resolution of (R, S)-ethyl-2-(4-hydroxyphenoxy) propanoate ((R, S)-EHPP) for production of (R)-ethyl-2-(4-hydroxyphenoxy) propanoate ((R)-EHPP). The key biocatalytic process parameters (pH, temperature, rotation speed and substrate concentration) were optimized. Under the optimum conditions, the optical purity of (R)-EHPP was improved up to >99% when the conversion was above 49%. A. oryzae WZ007 whole-cell lipase exhibited high reaction capacity, enantioselectivity and good reusability. The tolerable substrate concentration was 0.5 mol/L, and dry mycelium of A. oryzae WZ007 maintains over 80% of its initial activity after eight repeating cycles. Therefore the enzymatic preparation of (R)-EHPP route was suitable for industrial application.
- Zheng, Jian-Yong,Wu, Jia-Yu,Zhang, Yin-Jun,Wang, Zhao
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- Long-range chiral induction in chemical systems with helical organization. Promesogenic monomers in the formation of poly(isocyanide)s and in the organization of liquid crystals
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The preparation of optically active poly(isocyanide)s derived from chiral promesogenic monomers is reported. Remarkably, the stereogenic carbon atom in the monomer is able to pass its chiral 'information' to the growing polymer backbone which is at least
- Amabilino, David B.,Ramos, Elena,Serrano, José-Luis,Sierra, Teresa,Veciana, Jaume
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p. 9126 - 9134
(2007/10/03)
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- Evaluation of the Elbs Persulfate Oxidation Reaction for the Preparation of Aryloxyphenoxypropionate Herbicides
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A new, simple method for the preparation of several 4-(aryloxy)phenols (2a-d) and alkyl 2-(4-hydroxyphenoxy)propionates (3a,b) is described.These compounds are key precursors for the synthesis of important aryloxyphenoxypropionate herbicides (1a-d).The method uses the Elbs persulfate oxidation to convert phenol into 4-hydroxyphenyl sulfate (5).The free hydroxy group is then reacted with various aryl halides and alkyl 2-halopropionates.Mild hydrolysis of the sulfate group with boiling acetic acid then gives the products (2a-d) and (3a,b), generally in modest to good yield.
- Watson, Keith G.,Serban, Alexander
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p. 1503 - 1510
(2007/10/02)
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- The Synthesis and Transition Temperatures of Novel Low Molar Mass Cholesteric Materials Derived from (R)-2-(4-Hydroxyphenoxy)propanoic Acid
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A comprehensive series of (R)-2-(4-substituted-phenoxy)propanoates and (R)-2-(4-substituted-phenoxy)propanonitriles have been prepared.A wide variety of 4-substituents and ester functions have been examined to determine how the position of the chiral centre affects the cholesteric phase formation in these classes of materials; the synthesis of these novel materials, their transition temperatures and a procedure for assessing their optical purity are described and discussed.Mesogenicity is significantly depressed if the chiral centre is placed centrally within the molecule.
- Booth, Christopher J.,Gray, George W.,Toyne, Kenneth J.,Hardy, Judith
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- Process for the synthesis of phenoxyalkane derivatives
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The invention concerns a process for the synthesis of a compound of formula I STR1 wherein: U and V may be chosen from a range of substituents including hydrogen, halogen, alkyl and alkoxy; R1 and R2 may be chosen from a range of substituents including hydrogen and alkyl; n is 0, 1 or 2; and W may be chosen from a range of substitutents including the group STR2 which may be a free carboxylic acid or derivative thereof; the process comprising reacting a sulfate ester of formula II, wherein Q is a cation, with a compound of formula III, wherein L is a leaving group STR3 and hydrolyzing the sulfate ester formed. Preferably the sulfate ester of formula II is prepared by the oxidation of a phenol of formula IV with a persulfate. STR4
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- Process for producing 2-(4-hydroxyphenoxy) propionate derivatives
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A process for producing a 2-(4-hydroxyphenoxy) propionate derivative represented by the formula: STR1 where Alk is a C1 -C5 alkyl group, which comprises reacting a phenoxy propionate derivative represented by the formula: STR2 where Alk is as defined above, with a peroxide to obtain a formate derivative represented by the formula: STR3 where Alk is as defined above, and hydrolyzing the formate of the formula III.
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