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Amino Acid Methyl Esters (amino + acid_methyl_ester)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

N -(4-Nitrophenylsulfonyl)- and N -(Fluorenylmethoxycarbonyl)- N -ethyl Amino Acid Methyl Esters , A Practical Approach

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2010
Emilia Lucia Belsito
Abstract An efficient one-pot preparation of N -ethyl- N -4-nitrophenylsulfonyl (nosyl) amino acid methyl esters was accomplished by a simple N -ethylation reaction by using triethyloxonium tetrafluoroborate in the presence of N,N -diisopropylethylamine. The N -ethylated amino acid methyl esters are obtained with total retention of stereochemistry at the original chiral centers. To further broaden the scope of this methodology, the N -ethylated nosyl-protected compounds are easily converted in the more practical fluorenylmethyloxycarbonyl (Fmoc)-protected derivatives. The cleavage of methyl ester by using a mild and neutral method enables the preparation of N -ethyl amino acids that are building blocks suitable for introduction into a peptide chain. The methodology works well with both nosyl- and Fmoc-based solution-phase peptide synthesis. [source]

A Novel Synthesis, Including Asymmetric Synthesis of ,-Quaternary ,-Amino Acid Methyl Esters from Ketones via Sulfinyloxiranes.

CHEMINFORM, Issue 32 2005
Tsuyoshi Satoh
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

A Novel Synthesis of Cyclic ,-Amino Aldehydes, Amino Alcohols, and ,-Amino Acid Methyl Esters from Cyclic Ketones Through Sulfinylaziridines.

CHEMINFORM, Issue 34 2004
Hiroyuki Ota
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

N -(4-Nitrophenylsulfonyl)- and N -(Fluorenylmethoxycarbonyl)- N -ethyl Amino Acid Methyl Esters , A Practical Approach

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2010
Emilia Lucia Belsito
Abstract An efficient one-pot preparation of N -ethyl- N -4-nitrophenylsulfonyl (nosyl) amino acid methyl esters was accomplished by a simple N -ethylation reaction by using triethyloxonium tetrafluoroborate in the presence of N,N -diisopropylethylamine. The N -ethylated amino acid methyl esters are obtained with total retention of stereochemistry at the original chiral centers. To further broaden the scope of this methodology, the N -ethylated nosyl-protected compounds are easily converted in the more practical fluorenylmethyloxycarbonyl (Fmoc)-protected derivatives. The cleavage of methyl ester by using a mild and neutral method enables the preparation of N -ethyl amino acids that are building blocks suitable for introduction into a peptide chain. The methodology works well with both nosyl- and Fmoc-based solution-phase peptide synthesis. [source]

Chiral stationary phase covalently bound with a chiral pseudo-18-crown-6 ether for enantiomer separation of amino compounds using a normal mobile phase

CHIRALITY, Issue 3 2005
Keiji Hirose
Abstract In order to apply the excellent chiral recognition ability of chiral pseudo-18-crown-6 ethers that we developed to chiral separation, we prepared a chiral stationary phase (CSP) by immobilizing a chiral pseudo-18-crown-6-type host on 3-aminopropyl silica gel. A chiral column was prepared by the slurry-packing method in a stainless steel HPLC column. A liquid chromatography system using this CSP combined with the detection by mass spectrometry was used for enantiomer separation of amino compounds. A normal mobile phase can be used on this CSP as opposed to conventional dynamic coating-type CSPs. Enantiomers of 18 common natural amino acids were efficiently separated. The chiral separation observed for amino acid methyl esters, amino alcohols, and lipophilic amines was fair using this HPLC system. In view of the correlation between the enantiomer selectivity observed in chromatography and the complexion in solution, the chiral recognition in host,guest interactions might contribute to this enantiomer separation. Chirality 17:142,148, 2005. © 2005 Wiley-Liss, Inc. [source]

Chiral recognition of dipeptide methyl esters by an anionic ,-cyclodextrin

CHIRALITY, Issue 8 2001
Koji Kano
Abstract Chiral recognition of dipeptide methyl esters by anionic heptakis[6-carboxymethylthio-6-deoxy]-,-cyclodextrin (per-CO2, -,-CD) was studied in D2O at pD 7.0 by means of 1H NMR spectroscopy. The methyl esters of alanylalanine (Ala-Ala-OMe), alanylleucine (Ala-Leu-OMe), alanyltryptophan (Ala-Trp-OMe), glycyltryptophan (Gly-Trp-OMe), valyltryptophan (Val-Trp-OMe), leucyltryptophan (Leu-Trp-OMe), and tryptophylalanine (Trp-Ala-OMe) were used as the dipeptides. The binding constant (K) determined from NMR titration increases in the order Ala-Ala-OMe < Ala-Leu-OMe < Ala-Trp-OMe, suggesting that van der Waals interactions between the host and the guest participate in complexation. Coulomb interactions between the protonated dipeptide methyl esters and the anionic host seem to be another attractive force. Per-CO2, -,-CD interacts with the (R,R)-enantiomers of the dipeptide methyl esters more strongly than the (S,S)-enantiomers. Such enantioselectivity corresponds to that for ,-amino acid methyl esters such as Leu-OMe and Trp-OMe, whose (R)-enantiomers are the preferable guests. The enantioselectivity is mainly dominated by amino acid residue at the C -terminal and chirality at the N -terminal residue plays an assistant role. An asymmetrically twisted shape of the host cavity may be essential for chiral recognition. Chirality 13:474,482, 2001. © 2001 Wiley-Liss, Inc. [source]