01540nas a2200217   4500008004100000022001400041245013800055210006900193260000800262300001100270490000700281520072400288653001301012653003201025653003701057653003101094100001901125700002201144700002801166856012801194       2019                        eng d  a0040-403900aEfficient and convenient route for the synthesis of thiophene-2-carboxamidines as potential inhibitors of nitric oxide synthase (NOS)0 aEfficient and convenient route for the synthesis of thiophene2ca  cNOV  a1512540 v603 a<p>A mild and efficient synthesis of substituted thiophene-2-carboxamidines which are potent inhibitors of nitric oxide synthase (NOS) is reported herein. The key step involves reaction of a BOC-protected imidazolyl thiophene-2-carboxamidine reactive intermediate with various primary amines to form BOC-thio-phene-2-carboxamidines which could be readily deprotected using TFA to furnish free carboxamidines. The method is very mild and tolerates diverse substituents including sensitive peptide and amino acid fragments. This new methodology represents a substantial improvement to the literature method owing to its simplicity and hassle-free purification procedures. (C) 2019 Elsevier Ltd. All rights reserved.</p>
10aAmidines10aNitric oxide synthase (NOS)10aNitric oxide synthase inhibitors10aThiophene-2-carboxamidines1 aRashid, P., P.1 aSingh, Dharmendra1 aSanjayan, Gangadhar, J.  uhttps://library.ncl.res.in/content/efficient-and-convenient-route-synthesis-thiophene-2-carboxamidines-potential-inhibitors02198nas a2200205   4500008004100000022001400041245011300055210006900168260000800237490000700245520142100252653001301673653002901686653002501715653003501740653003401775100002901809700002601838856012801864       2025                        eng d  a1433-785100aKetenimine multicomponent strategy for multifaceted amidine functionalization of peptides on the solid phase0 aKetenimine multicomponent strategy for multifaceted amidine func  cSEP0 v643 a<p>
	The amidine group and its derivatives serve as proteolytically stable bioisosteres of the peptide bond, and their selective incorporation into peptides attributes significant chemical and biological features. This study introduces an efficient synthesis of amidine-containing peptides by a copper-catalyzed, solid-phase-compatible multicomponent reaction (MCR), leveraging ketenimine intermediates that are generated in situ. Through the reaction of sulfonyl azides with terminal alkynes and a wide variety of amines, we establish the robust on-resin synthesis of delta/epsilon-amidine amino acids, arginine isologues, fluorescently labeled peptides, drug-peptide hybrids, and PEGylated derivatives. This strategy notably supports a wide range of peptide modifications, including side chain alteration, amine functionalization, and peptide macrocyclization through both backbone and side chain groups, as well as incorporating aromatic scaffolds into the peptide backbone. The methodology demonstrates broad substrate tolerance, compatibility with peptide chemistry protocols, and access to complex motifs, including pharmacophores and imaging tags, all within a single reaction platform. Our results underscore the synthetic versatility and functional applicability of ketenimine-based MCRs for advanced peptide modification, expanding the chemical space of peptide medicinal chemistry and therapeutics.</p>
10aAmidines10amulticomponent reactions10apeptide modification10aPeptide-small molecule hybrids10aSolid phase peptide synthesis1 aBodake, Supriya, Mahadev1 aMarelli, Udaya, Kiran  uhttps://library.ncl.res.in/content/ketenimine-multicomponent-strategy-multifaceted-amidine-functionalization-peptides-solid