- Di[(R)-2-ethylhexyl] phthalate, a bioactive metabolite first isolated from three different bacillus species, and its synthesis
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Di(2-ethylhexyl) phthalate (DEHP) is the most common phthalate ester, which has been used as a plasticizer for the production of numerous polymers, particularly polyvinyl chloride (PVC). Many other groups have synthesized meso-DEHP indicating interest in this molecule, but we are the first to synthesize enantiomerically pure di[(R)-2-ethylhexyl] phthalate. We report herein, for the first time, the isolation-from the cultures of Bacillus thuringiensis, B. subtilis, and B. velezensis strains-of di[(R)-2-ethylhexyl] phthalate, enantiomerically pure and in good yields: its biological activity against bacteria and fungi was probed and for the first time its synthesis was done.
- Castro, Miriam,Jiménez, Jacqueline,Ortiz, Aurelio,Sansinenea, Estibaliz
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- Lipase-catalyzed transesterification of primary alcohols: Resolution of 2-ethylhexan-1-ol and 2-ethylhex-5-en-1-ol
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Both the (R) and (S) enantiomers of 2-ethylhex-5-en-1-ol (R)-(-)-1, (S)-(+)-1 and 2-ethylhexan-1-ol (R)-(-)-2, (S)-(+)-2 were prepared in good yields and in high enantiomeric excess via lipase-catalyzed transacetylation of racemic alcohols 1 and 2 with vinyl acetate. Various experimental conditions (lipase PSL or PLF, solvent and temperature ranging from 30 to -30°C) are used and their influence on the enantioselectivity and on the reaction rate is evaluated. The (S) unsaturated alcohol 1 is specifically esterified by lipase PS in CH2Cl2 at 0°C with a very high enantiomeric ratio (E ~ 750) thus allowing the production of both enantiomers (R)-(-)-1 and (S)-(+)-1 with fairly good yields from the same enzymatic transformation. The comparison of unsaturated and saturated primary alcohols 1 and 2 shows that, for a similar atomic framework, the enantioselectivity of PSL is greatly enhanced by the presence of a terminal double bond. On the other hand, an enhancement of PSL enantioselectivity without loss of catalytic activity is achieved by decreasing the temperature to -30°C thus giving access to both enantiomers.
- Baczko, Krystyna,Larpent, Chantal
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p. 521 - 526
(2007/10/03)
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