Microwave assisted facile synthesis of amino acid benzyl esterp-toluenesulfonate and hydrochloride salts

Vasanthakumar, Ganga-Ramu; Patil, Basanagoud S.; Babu, Vommina V. Suresh

doi:10.1007/bf02538385

Cited by 4 publications

(4 citation statements)

References 16 publications

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“…N ‐For‐amino acids 1 were made and transformed to the corresponding methyl, ethyl or benzyl esters 2 42, 43. The next step is the preparation of isonitriles which is the key aspect from the point of maintaining the enantiomeric purity.…”

Section: Resultsmentioning

confidence: 99%

Isoselenocyanates derived from amino acid esters: an expedient synthesis and application to the assembly of selenoureidopeptidomimetics, unsymmetrical Selenoureas and selenohydantoins

Hemantha

Sureshbabu

2010

Journal of Peptide Science

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An important class of organoselenium compounds-α-isoselenocyanato esters 4 has been prepared by a reaction of α-isocyano esters with elemental selenium powder. The reaction issimple, rapid and all the isoselenocyanates have been isolated as stable ones after chromatographic purification. These hitherto unreported classes of molecules would be useful building blocks for the preparation of variety of selenium containing peptidomimetics. In this study, the utility of the title molecules in the preparation of selenoureidopeptidomimetics 6, unsymmetrical selenoureas 8 and selenohydantoins 10 is demonstrated.

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Section: Resultsmentioning

confidence: 99%

Isoselenocyanates derived from amino acid esters: an expedient synthesis and application to the assembly of selenoureidopeptidomimetics, unsymmetrical Selenoureas and selenohydantoins

Hemantha

Sureshbabu

2010

Journal of Peptide Science

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“…In some other cases, coupling agents (e.g., carbodiimide) [ 18 ] need to be employed or poorly atom efficient protocols with several reaction steps (protection, esterification and deprotection) as well as the use of expensive N -protected amino acids starting materials [ 19 , 20 , 21 ]. Many of such protocols also have a limited scope [ 22 ]. Comparatively, few heterogeneous catalysts including ionic liquids have been described as efficient systems to prepare short alkyl amino acid esters via esterification of amino acids [ 23 , 24 ] but these approaches have a limited applicability (e.g., nitrogen atmosphere) and/or suffer from many of the aforementioned drawbacks.…”

Section: Introductionmentioning

confidence: 99%

“…The proposed approach could be efficiently extended to the synthesis of long and short chain alkyl and aryl esters. To the best of our knowledge, this is the first report of a general procedure for the esterification of unprotected amino acids under microwave irradiation, despite other investigations related to the esterification of amino acids under microwave irradiation [ 19 , 20 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Efficient Microwave-Assisted Synthesis of Ionic Esterified Amino Acids

et al. 2011

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In this work, an efficient microwave-assisted methodology for the esterification of unprotected α-amino acids is described. Ionic esterified amino acids were synthesized in satisfactory yields in a facile one-pot solventless protocol from unprotected amino acids and alcohols under acid catalysis (MsOH or p-TsOH) to afford the pure products after a simple work-up procedure. This procedure can also be extended to the preparation of long and short chain alkyl and benzyl esters.

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“…The formation of 1 was complete in 25 min, and workup of the reaction mixture resulted in pure peptide in 93% yield. Tos·H 2 N-Ala-OBzl was synthesized following the microwave irradiation method, and the tosyl salt was neutralized with aqueous Na 2 CO 3 prior to coupling. The resulting amino-free amino acid benzyl ester was extracted into DCM and used directly for coupling.…”

mentioning

confidence: 99%

Total Synthesis of Cyclosporin O by Convergent Approach Employing Fmoc-Amino Acid Chlorides Mediated by Zinc Dust

et al. 2007

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An epimerization free and efficient total synthesis of immunosuppressant cyclosporin O (CsO) by step-by-step assembly of amino acids in solution phase is reported. The couplings were performed by employing Fmoc-amino acid chlorides and were mediated by zinc dust under neutral conditions. The yield and purity of the coupling of sterically hindered N-methylamino acids to N-methylamino acids at positions 8, 9, 10, and 11 were enhanced by repeating the coupling thrice at these particular junctures. All the 10 intermediate peptides pertaining to CsO and the final CsO were isolated and completely characterized through IR, 1H NMR, mass spectrometry, and HPLC techniques.

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Microwave assisted facile synthesis of amino acid benzyl esterp-toluenesulfonate and hydrochloride salts

Cited by 4 publications

References 16 publications

Isoselenocyanates derived from amino acid esters: an expedient synthesis and application to the assembly of selenoureidopeptidomimetics, unsymmetrical Selenoureas and selenohydantoins

Isoselenocyanates derived from amino acid esters: an expedient synthesis and application to the assembly of selenoureidopeptidomimetics, unsymmetrical Selenoureas and selenohydantoins

Efficient Microwave-Assisted Synthesis of Ionic Esterified Amino Acids

Total Synthesis of Cyclosporin O by Convergent Approach Employing Fmoc-Amino Acid Chlorides Mediated by Zinc Dust

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