• Title/Summary/Keyword: Acylations

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Recent Developments and Prospects in the Enzymatic Acylations (효소를 이용한 아실화 반응의 최근 동향과 전망)

  • Park, Oh-Jin
    • Korean Chemical Engineering Research
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    • v.51 no.6
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    • pp.716-726
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    • 2013
  • Enzymatic acylations catalyzed by hydrolytic enzymes, along with enzymatic hydrolysis, are established reactions in the synthesis of fine chemicals such as chiral intermediates and polymerizations in the industry. Those reactions have been carried out mostly in organic media due to the thermodynamic limitations. Recently, there have been reports on enzymatic acylations in aqueous media. They have dealt with the elucidation of reaction mechanisms of hydrolases and acyl transferases based on their X-ray structures, homology comparison of the two kinds of enzymes, substrate engineering of acyl donors and computational design of acyl transferases for enzymatic acylations in aqueous media. Enzymatic acylations play an important role in the combinatorial synthesis of natural products such as polyketides and nonribosomal peptides. In this review, the historic developments of enzymatic acylations and industrial examples are described briefly. In addition, recent developments of enzymatic acylations in the modification of natural products and their prospects will be discussed.

Semiempirical Molecular Orbital Calculations of the Substituent Effects on Acylations of 3-Cephem Analogues

  • Chang Moon-Ho;Koh Hun-Yeong;Lee Jung-Chull;Lee Yoon Sup
    • Bulletin of the Korean Chemical Society
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    • v.15 no.6
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    • pp.453-455
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    • 1994
  • Semiempirical MO calculations are applied to estimate the substituent effects on acylations of the nonfused N-vinyl-2-amino $\beta-lactams$ having frameworks analogous to 3-cephems. The stabilization energy for the reaction intermediate of the nucleophilic attack by the hydroxide ion is selected as the reactivity index and calculated by AM1 and PM3 methods for the model $\beta-lactams$ with substituents at the C1 and N-vinyl terminal positions. The reactivities are larger for -SH connected to the C1 and strong $\pi-acceptors$ at the N-vinyl terminal implying the large reactivity for known active cephalosporins. Quantum chemical calculation of stabilization energy could be useful in correlating antibiotic activities of many compounds obtained as derivatives of a lead compound.

N-Acyl Amino Acid Surfactant(15) Synthesis and Properties of Sodium N-(2-Dodecyl Succinoyl) l-Glutamate (N-아실아미노산계 계면활성제 (제15보) Sodium N-(2-Dodecyl Succinoyl) l-Glutamate의 합성 및 계면성)

  • Kwack, Kwang-Soo;Yoon, Young-Kyoon;Jeong, Noh-Hee;Kim, Duck-Gwon;Nam, Ki-Dae
    • Journal of the Korean Applied Science and Technology
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    • v.18 no.1
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    • pp.55-59
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    • 2001
  • These N-acyl amino acid surfactants is normally produced by reaction of acid anhydride with sodium ${\ell}-glutamate$ hydrolysates under Schotten-Baumann condition i.e., in alkaline aqueous medium. To avoid using fatty acid chlorides, acylations were also carried out with the fatty acids themselves or with their methyl esters, but unfortunately these methods cannot be used in practice, dodecenyl succinic anhydride, was to be studied for their suitability as acylating agents the production if acylated glutamine hydrolysates. The surface activities including surface tension forming power, forming stability and emulsifying power were measured. The experimental results revealed that the products have a good emulsifying power. Thus, there derivatives will be expected to be used an emulsifying agent for O/W type cosmetic emulsion.