N. S. Sudarshan

Synthesis of 4-Amino-Thiazole Analogs of Fmoc-Amino Acids and Thiazole Linked N-Orthogonally Protected Dipeptidomimetics

We report a one pot synthesis of Fmoc amino acid derived 4-amino-thiazole derivatives and thiazole linked N-orthogonally protected dipeptidomimetics by the condensation of N(alpha)-Fmoc alpha-halomethylketones with thiourea and Boc/Z-alpha-amino acid thioamides via modified Hantzch protocol. Side chain modified Fmoc amino acids containing 4-amino thiazole moiety have also been synthesized following the similar protocol.

Peptidyl Carbamates: Efficient Synthesis Using N-Fmoc-β-aminoalkoxy Carbonyl Chlorides/Active Pentachlorophenyl Carbonates as Monomeric Building Blocks

A simple protocol for the synthesis of linear peptidylcarbamates employing Fmoc-β-aminoalkoxy carbonyl chlorides is described. The N-Fmoc-β-aminoalkoxy carbonyl chlorides were prepared by the reaction of phosgene or triphosgene with Fmoc-protected β-amino alcohol which were isolated as solids. These oxycarbonyl chlorides were also converted to the corresponding pentachlorophenyl carbonates by reacting with pentachlorophenol. Fmoc-β-aminoalkoxy carbonyl chlorides as well as pentachlorophenol carbonates were successfully used as monomeric building blocks for the synthesis of several peptidyl carbamates.

Efficient Synthesis of O-Succinimidyl-(tert-Butoxycarbonylamino)methyl Carbamates Derived from α-Amino Acids Accelerated by Ultrasound: Application to the Synthesis of Ureidodipeptides

Abstract The synthesis of O-succinimidyl-(tert-butoxycarbonylamino)methyl carbamates employing isocyanates made through the Curtius rearrangement of Boc-amino acid azides in the presence of N-hydroxysuccinimide under the influence of ultrasound is described.

Synthesis of Ureidopeptides and Peptidyl Ureas Employing Bsmoc Chemistry

This work describes the utility of Bsmoc group in the synthesis of ureidopeptides and peptidyl ureas. The reaction of isocyanates derived from Bsmoc-α-amino acids with amino acid ester has yielded the ureidopeptides in good yields. The isocyanates were obtained by subjecting Bsmoc-amino acid azides to Curtius rearrangement. Bsmoc protected ureidopeptides have been isolated as solids and characterized by 1H NMR, 13C NMR and mass spectrum.

Synthesis of N-urethane protected β-amino alcohols employing N-(protected-α-aminoacyl)benzotriazoles

A simple and racemisation-free synthesis of N-urethane protected α-amino/peptidyl alcohols by the reduction of the corresponding easily accessible N-acylbenzotriazoles is described. The method is practical, straightforward, fast and efficient for the synthesis of amino/peptidyl alcohols. All the alcohols made were isolated in high yields and purity.

HOBt·DCHA-Mediated Synthesis of Sterically Hindered Peptides employing Fmoc-Amino Acid Chlorides in Both Solution-Phase and Solid Phase Methods

Abstract The synthesis of peptides employing Fmoc-amino acid chlorides in presence of HOBt·DCHA salt in solution as well as by the solid-phase methods is described. The coupling was found to be complete in 30 min and free from racemization. The synthesis of β-casomorphin by solid-phase protocol employing Fmoc-amino acid chloride/HOBt·DCHA in DMF–CH2Cl2 has also been outlined. The final peptide was obtained in 80% yield and was fully characterized.

Synthesis of Peptidyl Ureas Employing O-succinimidyl-(9H-fluoren-9- ylmethoxycarbonylamino)methylcarbamate Derivatives as Activated Monomers

A convenient and efficient method for the synthesis of dipeptidyl ureas and urea acids employing O-succinimidyl-(9H-fluoren-9-ylmethoxycarbonyl amino)methylcarbamates has been described. All the compounds, obtained in good yields, have been fully characterized by mass and NMR spectra.