Synthesis of cyclic peptides constrained with biarylamine linkers using buchwald-hartwig C-N coupling

In this paper, we describe the synthesis of conformationally constrained cyclic peptides with biarylamine linkers for peptidomimetics using palladium-catalyzed intramolecular Buchwald-Hartwig C-N coupling. We have prepared a variety of di-, tri-, and tetrapeptides (16-22-membered) in good yields using this reaction

Synthesis of conformationally constrained cyclic peptides using an intramolecular sonogashira coupling

Small peptides having a 3-bromobenzyl group at the C-termini and n-alkynoyl group at the N-termini undergo a smooth copper-free intramolecular Sonogashira coupling reaction to afford the corresponding cyclic peptides in moderate yields. Scope and limitations of this macrocyclization is demonstrated with di-, tri-, and tetrapeptides

Synthesis of small cyclic peptides constrained with 3-(3-aminomethylphenyl)propionic acid linkers using free radical-mediated macrocyclization

In this letter, we report that small peptides (di- and tri-) having a 3-bromobenzyl group at the C-termini and an acryloyl group at the N-termini undergo an efficient Bu3SnH–AIBN mediated intramolecular free radical cyclization to afford cyclic peptides in good yields. We also propose that these cyclizations are occurring via a pre-organized acyclic structure dictated by a reverse turn (γ/β-turn)

Synthesis of impurity A in Carvedilol: a β-adrenergic receptor

741-745Carvedilol is prepared by different synthetic approaches. Almost in all the approaches the major impurities that are known in the literature A, B, C, D and E are listed in European pharmacopoeia. The control of pharmaceutical impurities is currently a critical issue to the pharmaceutical industry. In this publication, a description of these impurities and their origins in Carvedilol process are presented along with the preparation of impurity A

Synthesis of an amino moiety in trovafloxacin by using an in-expensive amidine base, <i style="">N,N</i>-diethylacetamidine

569-573 The simple and in-expensive amidine base, N,N-diethylacetamidine, has been prepared and utilized in the construction of bicyclic hetero compound, 4 and employed for further reduction of amidic carbonyl groups of 4 by using NaBH4/I2-THF condition which is an efficient and commercially viable method to prepare 5 towards the synthesis of amino moiety 1, in Trovafloxacin 2 an antibacterial agent. </smarttagtype

A facile Ph₃P/CO₂ mediated, one-pot synthesis of 2-oxazolidinones from 1,2-azido alcohols <i style="">via</i> phosphazene and isocyanate intermediates

978-984A facile, efficient and convenient method has been developed for the one-pot synthesis of 2-oxazolidinones from the corresponding 1,2-azido alcohols via phosphazene and isocyanate intermediates in presence of Ph3P/CO2 in toluene