Synthesis of Fmoc-amino acid chlorides assisted by ultrasonication, a rapid approach

Kantharaju,; Patil, Basanagoud S.; Babu, Vommina V. Suresh

doi:10.1007/bf02538388

Cited by 11 publications

(13 citation statements)

References 15 publications

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“…In order to elaborate a tripeptide building block suitably protected for peptide synthesis we decided to perform the coupling reaction with a Fmoc-protected amino acid chloride; Fmoc-alanine chloride was efficiently prepared by a reported procedure. [13] Treatment of this amino acid chloride (1.1 equiv.) with the dipeptide (R,S)-13, containing the trifluoromethyl group, gave the corresponding tripeptide (S,R,S)-14 in 74 % yield without any epimerization (Scheme 4).…”

Section: Resultsmentioning

confidence: 99%

“…1 H NMR (400.00 MHz), 13 C NMR (100.50 MHz), and 19 F NMR (376.20 MHz) were measured with a JEOL 400 spectrometer. Chemical shifts of 1 H NMR were expressed in parts per million downfield from tetramethylsilane (δ = 0 ppm) in CDCl 3 .…”

Section: Methodsmentioning

confidence: 99%

“…),7.74 (d,J = 8.7 Hz, 1 H, NH Leu) ppm. 13 C NMR (100.5 MHz, CDCl 3 ): δ = 21.7 (CH 3 , C δ Leu), 22.8 (CH 3 , C δ Leu), 25.0 (CH, C γ Leu), 25.4 (CH 2 , C γ Pro), 32.4 (CH 2 , C β Pro), 41.1 (CH 2 , C β Leu), 47.6 (CH 2 , C δ Pro), 50.9 (CH, C α Leu), 67.1 (CH 2 , Bn CH 2 ), 70. CHCl 3 13 C NMR (100.5 MHz, CDCl 3 ): δ = 20.9 (CH 3 , C β Ala), 27.9 (3 ϫ CH 3 , tBu CH 3 ), 37.6 (CH 2 , C β Phe), 53.4 (CH, C α Phe), 60.6 (C, q, J = 26.8 Hz, C α Ala), 82.5 (C, tBu C), 125.7 (C, q, J = 284.7 Hz, CF 3 ), 127.0 (CH, Phe arom.…”

Section: (S)-α-tfm-pro-l-ala-obn [(Ss)-2]mentioning

confidence: 97%

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Convenient Synthesis of N‐Terminal Tfm‐Dipeptides from Unprotected Enantiopure α‐Tfm‐Proline and α‐Tfm‐Alanine

et al. 2009

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A convenient procedure for the synthesis of highly lipophilic dipeptide building blocks from enantiopure α‐trifluoromethyl α‐amino acids is reported. Coupling reactions at the C termini of the trifluoromethyl α‐amino acids were successfully performed with totally unprotected amino acids without formation of diketopiperazines. The synthesis of a tripeptide through a coupling reaction at the deactivated N‐terminal position was achieved. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: (S)-α-tfm-pro-l-ala-obn [(Ss)-2]mentioning

confidence: 97%

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Convenient Synthesis of N‐Terminal Tfm‐Dipeptides from Unprotected Enantiopure α‐Tfm‐Proline and α‐Tfm‐Alanine

et al. 2009

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“…However this reaction required the prior preparation of highly electrophilic Fmoc-protected amino acid chlorides (Patil and Babu 2002;Chaume et al 2013) and specific reaction conditions (3 h at 100 °C in a sealed tube in acetonitrile). After a reverse phase semi-preparative HPLC purification the corresponding dipeptides (R)-7, (R)-8 and (R)-9 were obtained in 85, 78 and 90 %, respectively (Scheme 3).…”

Section: Synthesis Of α-Tfm-ala Containing Dipeptides Designed For Somentioning

confidence: 99%

“…The Fmoc-amino acid chlorides were prepared according to previously reported procedures (Patil and Babu 2002;Chaume et al 2013).…”

Section: Syntheses Of Fmoc-aa-(r)-α-tfm-ala-oh Dipeptidesmentioning

confidence: 99%

Synthesis of protected enantiopure (R) and (S)-α-trifluoromethylalanine containing dipeptide building blocks ready to use for solid phase peptide synthesis

et al. 2016

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Considering the increasing importance of fluorinated peptides, the development of efficient and reliable synthetic methods for the incorporation of unnatural fluorinated amino acids into peptides is a current matter of interest. In this study, we report the convenient Boc/benzyl and Cbz/tert-butyl protection of both enantiomers of the quaternarized amino acid α-trifluoromethylalanine [(R)- and (S)-α-Tfm-Ala]. Because of the deactivation of the nitrogen atom of this synthetic amino acid by the strong electron withdrawing trifluoromethyl group, the peptide coupling on this position is a challenge. In order to provide a robust synthetic methodology for the incorporation of enantiopure (R)- and (S)-α-trifluoromethylalanines into peptides, we report herein the preparation of dipeptides ready to use for solid phase peptide synthesis. The difficult peptide coupling on the nitrogen atom of the α-trifluoromethylalanines was performed in solution phase by means of highly electrophilic amino acid chlorides or mixed anhydrides. The synthetic effectiveness of this fluorinated dipeptide building block strategy is illustrated by the solid phase peptide synthesis (SPPS) of the Ac-Ala-Phe-(R)-α-Tfm-Ala-Ala-NH2 tetrapeptide.

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A recent update on new synthetic chiral compounds with antileishmanial activity

2022

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Parasitic diseases, including malaria, leishmaniasis, and trypanosomiasis, affect billions of people and are responsible for almost 500,000 deaths/year. In particular, leishmaniasis, a neglected tropical disease, is considered a global public health problem because current drugs have several drawbacks including to toxicity, high cost, and drug resistance, which result in a lack of effective and readily available therapies. Therefore, the synthesis of new, safe, and effective molecules still requires the attention of the scientific community. Moreover, it is well known that chirality plays a crucial role in the antiparasitic activity of molecules, driving the design of their synthesis. Therefore, in this review we report a recent update on new chiral compounds with promising antileishmanial activity, focusing on synthetic approaches. Where reported, in most cases the enantiopure compound has shown better potency against the protozoa than its enantiomer or corresponding racemic mixture.

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Synthesis of Fmoc-amino acid chlorides assisted by ultrasonication, a rapid approach

Cited by 11 publications

References 15 publications

Convenient Synthesis of N‐Terminal Tfm‐Dipeptides from Unprotected Enantiopure α‐Tfm‐Proline and α‐Tfm‐Alanine

Convenient Synthesis of N‐Terminal Tfm‐Dipeptides from Unprotected Enantiopure α‐Tfm‐Proline and α‐Tfm‐Alanine

Synthesis of protected enantiopure (R) and (S)-α-trifluoromethylalanine containing dipeptide building blocks ready to use for solid phase peptide synthesis

A recent update on new synthetic chiral compounds with antileishmanial activity

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