A simple method for the synthesis of long-chain alkyl esters of amino acids

Penney, Christopher; Shah, Pravinkant; Landi, S.

doi:10.1021/jo00209a018

Cited by 32 publications

(25 citation statements)

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“…D-, L-, and DL-Alanine Octadecyl Ester (Ala-C 18 ). The free amine was prepared according to Penney et al 16 and was further purified by column chromatography (silica gel, ethyl acetate:n-hexane:acetone ratio of 5:4.5:0.5). 1 18 ).…”

Section: Methodsmentioning

confidence: 99%

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Structure and Reactivity in Langmuir Films of Amphiphilic Alkyl and Thio-alkyl Esters of α-Amino Acids at the Air/Water Interface

et al. 2004

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The structure and reactivity of alkyl esters of several R-amino acids self-assembled at the air/water interface have been investigated as part of our studies on mechanisms that are possibly relevant for the generation of homochiral prebiotic peptides. Grazing incidence X-ray diffraction (GIXD) studies of monolayers of racemic and enantiopure alkyl esters and thio-esters of alanine on the water surface demonstrated that these racemates self-assemble in the form of mixed solid solutions, because of disorder of the headgroups of the two enantiomers (enantiomeric disorder) within the two-dimensional (2D) crystallites. Matrix-assisted laser-desorption ionization time-of-flight Mass Spectrum (MALDI-TOF MS) analysis of the products collected from the air/water interface indicated the formation of low-molecular-weight oligopeptides (primarily dimers) and, in the case of some of the thioesters, small quantities of trimers and tetramers. Mass spectrometric studies on the diastereoisomeric distribution of the oligopeptides, starting from deuterium enantio-labeled monomers, demonstrated binomial statistics, such as that in reactions occurring in an isotropic environment. The alkyl esters of phenylalanine and tyrosine did not form 2D crystallites at the air/water interface, and, upon polycondensation, they yielded only dipeptides. The enantiomeric disorder within the 2D crystallites of the monomers of the alkyl esters and thioesters of racemic serine was absent. Polycondensation of these esters, however, yielded only dipeptides and tripeptides and they were not investigated further. In contrast to previous reports, the present studies demonstrate that this reaction does not proceed beyond the dipeptide stage and, therefore, cannot be regarded as a plausible system for the generation of prebiotic peptides.

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Section: Methodsmentioning

confidence: 99%

“…1 18 ). The free amine was prepared according to Penney et al 16 16 The free amine was released from the hydrochloride salt by extraction with a triethylamine/water mixture and recrystallized from n-hexane. 1 16 and recrystallized from CH 2 Cl 2 .…”

Section: Methodsmentioning

confidence: 99%

Structure and Reactivity in Langmuir Films of Amphiphilic Alkyl and Thio-alkyl Esters of α-Amino Acids at the Air/Water Interface

et al. 2004

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“…Esters of Lphenylalanine were synthesized following the procedure described by Penney et al (1985). DTPA bisamides derived from L-phenylalanine esters were prepared using the procedure of Zhao ( Zhao et al 1997).…”

Section: Synthesis Of the Ligandsmentioning

confidence: 99%

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

et al. 2005

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Three amphiphilic DTPA bisamide derivatives containing long-chain phenylalanine esters (with 14, 16 and 18 carbon atoms in the alkyl chain) were synthesized and their corresponding gadolinium(III) complexes were prepared. The attempts to form paramagnetic micelles carrying the gadolinium(III) complexes yielded unstable or polydisperse micelles implying that the presence of the bulky aromatic side groups in the amphiphilic Gd-DTPA bisamide complexes results in an inefficient packing of the paramagnetic complex into micelles. All complexes were efficiently incorporated into liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), yielding stable and monodisperse paramagnetic liposomes. All liposomes had a comparable size, typically between 120 and 160 nm. As a result of the reduced mobility of the gadolinium(III) complexes, solutions of these supramolecular structures show a higher relaxivity than solutions of Gd-DTPA. However, the relaxivity gain is lower compared to compounds consisting of purely aliphatic chains of the same length, most likely due to the less efficient packing or increased local mobility of the gadolinium(III) complex. In the case of the Gd-DTPA bisamide complex with 18 carbon atoms, the immobilization inside the liposomal structure is less effective, probably because the aliphatic chains of the complex are longer than the alkyl chains of the DPPC host, resulting in a relatively high local mobility. The paramagnetic liposomes containing the Gd-DTPA bisamide complexes with 14 carbon atoms showed the highest relaxivity because the optimal length match between the hydrophobic chains of the DPPC and the ligand allowed very efficient packing of the paramagnetic complex into the liposome.

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“…To date, the principal method of amino acid ester synthesis using alcohols has been the Fischer-Speier esterification procedure [17], in which an amino acid and an alcohol are dehydrated in the presence of an acid catalyst, such as hydrogen chloride [18], sulfuric acid [19], polyphosphoric acid [20], p-toluenesulfonic acid [21,22], ion-exchange resins (e.g., Amberlyst® 15) [23], or trimethylchlorosilane [24]. However, as the amino group present in amino acids can form an amide moiety through bonding with the carboxylic group of another molecule, the amino group must be protected prior to esterification.…”

Section: Introductionmentioning

confidence: 99%

Microwave-Assisted Facile and Rapid Esterification of Amino Acids I: Esterification of L-Leucine from Batch to Flow Processes and Scale-Up

Nagahata¹,

Nakamura²,

Mori³

et al. 2017

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We herein report our studies into the effects of microwave irradiation on the sol-vent-free esterification of L-leucine with alcohols. In the absence of solvent, micro-wave irradiation accelerated the reaction compared to conventional oil bath heating. Measurement of the dielectric properties under the reaction conditions revealed that the high dielectric loss factor of the reaction mixture containing L-leucine, n-butanol, and a p-toluene sulfonic acid catalyst could be attributed to the acceleration of the reaction. The depth of microwave penetration into the reaction mixture as derived from the in-situ measurement of the dielectric properties was ~13 mm, which suggested that a thinner reaction vessel was favorable for the esterification of L-leucine. In addition to the batch reaction using a desktop microwave reactor, two types of flow reaction were also performed using a desktop tubular reactor and a semi-bench-scale tubular reactor. These flow reactions also exhibited high performances, thus allowing the scale-up of this reaction system for industrial use.

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A simple method for the synthesis of long-chain alkyl esters of amino acids

Cited by 32 publications

References 0 publications

Structure and Reactivity in Langmuir Films of Amphiphilic Alkyl and Thio-alkyl Esters of α-Amino Acids at the Air/Water Interface

Structure and Reactivity in Langmuir Films of Amphiphilic Alkyl and Thio-alkyl Esters of α-Amino Acids at the Air/Water Interface

Paramagnetic liposomes containing amphiphilic bisamide derivatives of Gd-DTPA with aromatic side chain groups as possible contrast agents for magnetic resonance imaging

Microwave-Assisted Facile and Rapid Esterification of Amino Acids I: Esterification of L-Leucine from Batch to Flow Processes and Scale-Up

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