- Total Synthesis and Determination of the Absolute Configuration of Rakicidin C
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The absolute configuration of rakicidin C was predicted by comparison of optical rotation data and absolute configuration of APD-cyclic depsipeptides and further determined by total synthesis. The absolute configuration of five chiral centers was determin
- Han, Fangzhi,Liu, Guangju,Jin, Chaofan,Wang, Jinghan,Liu, Jianwei,Wang, Liang,Chen, Yue
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supporting information
p. 7069 - 7073
(2021/09/14)
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- Determination of Chemical and Enantiomeric Purity of α-Amino Acids and their Methyl Esters as N-Fluorenylmethoxycarbonyl Derivatives Using Amylose-derived Chiral Stationary Phases
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Liquid chromatographic enantiomer separation and simultaneous determination of chemical and enantiomeric purity of α-amino acids and their methyl esters as N-fluorenylmethoxycarbonyl (FMOC) derivatives was performed on three covalently bonded type chiral stationary phases (CSPs) derived from amylose derivatives. The enantiomer separation of α-amino acid esters as N-FMOC derivatives was better than that of the corresponding acids, especially for CSP 1 and 2. Chemical impurities as the corresponding racemic acids present in several commercially available racemic amino acid methyl esters were observed to be 0.49–17.50%. Enantiomeric impurities of several commercially available L-amino acid methyl esters were found to be 0.03–0.58%, whereas chemical impurities as the corresponding racemic acids present in the same analytes were found to be 0.13–13.62%. This developed analytical method will be useful for the determination of chemical and enantiomeric purity of α-amino acids and/or esters as N-FMOC derivatives using amylose-derived CSPs.
- Islam, Md. Fokhrul,Adhikari, Suraj,Paik, Man-Jeong,Lee, Wonjae
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p. 332 - 338
(2019/04/13)
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- Highly Chemoselective Deprotection of the 2,2,2-Trichloroethoxycarbonyl (Troc) Protecting Group
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Nonreducing, pH-neutral conditions for the selective cleavage of the 2,2,2-trichloroethoxycarbonyl (Troc) protecting group are reported. Using trimethyltin hydroxide in 1,2-dichloroethane, Troc-protected alcohols, thiols, and amines can be selectively unmasked in the presence of various functionalities that are incompatible with the reducing conditions traditionally used to remove the Troc group. This mild deprotection protocol tolerates a variety of other hydrolytically sensitive and acid/base-sensitive moieties as well.
- Trost, Barry M.,Kalnmals, Christopher A.,Tracy, Jacob S.,Bai, Wen-Ju
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supporting information
p. 8043 - 8046
(2019/01/04)
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- Modulating OxyB-Catalyzed Cross-Coupling Reactions in Vancomycin Biosynthesis by Incorporation of Diverse d -Tyr Analogues
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We report a general method for synthesizing diverse d-Tyr analogues, one of the constituents of the antibiotic vancomycin, using a Negishi cross-coupling protocol. Several analogues were incorporated into the vancomycin substrate-peptide and reacted with
- Ozturk, Seyma,Forneris, Clarissa C.,Nguy, Andy K.L.,Sorensen, Erik J.,Seyedsayamdost, Mohammad R.
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p. 7309 - 7317
(2018/06/04)
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- An α-formylglycine building block for Fmoc-based solid-phase peptide synthesis
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(Chemical Equation Presented) Nearly all known sulfatases share a common active site modification that is required for their activity: conversion of cysteine to α-formylglycine. We report the synthesis of an α-formylglycine building block suitable for Fmo
- Rush, Jason,Bertozzi, Carolyn R.
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p. 131 - 134
(2007/10/03)
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- Synthesis of a chiral precursor for no-carrier-added (NCA) PET tracer 6- [18F]fluoro-L-dopa based on regio- and enantioselective alkylation of 2,4- bis(chloromethyl)-5-iodoanisole
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(2S,5S)-5-(3-Formyl-6-iodo-4-methoxybenzyl)-1-t-butoxycarbonyl-2-t- butyl-3-methyl-4-imidazolidinone (11), a chiral intermediate towards NCA PET tracer 6-[18F]fluoro-L-dopa (1), was synthesized from 3-iodoanisole in four steps. 3-Iodoanisole was first bischloromethylated to 2,4-bis(chloromethyl)- 5-iodoanisole (14). Regio- and enantio-selective alkylation of 14 with (S)-1- (t-butoxycarbonyl)-2-t-butyl-3-methyl-4-imidazolidinone (12) afforded 33, which was then hydrolyzed and oxidized to the desired intermediate 11.
- Kuroda, Chiaki,Ochi, Atsushi,Nakane, Noritoshi,Umeyama, Takashi,Muto, Nobuko,Niimura, Nami,Teramoto, Yoshiki,Nogami, Hiroyuki,Reddy, Guvvala N.
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p. 417 - 422
(2007/10/03)
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