@article {46429,
	title = {Efficient and convenient route for the synthesis of thiophene-2-carboxamidines as potential inhibitors of nitric oxide synthase (NOS)},
	journal = {Tetrahedron Letters},
	volume = {60},
	year = {2019},
	month = {NOV},
	pages = {151254},
	type = {Article},
	abstract = {<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>
},
	keywords = {Amidines, Nitric oxide synthase (NOS), Nitric oxide synthase inhibitors, Thiophene-2-carboxamidines},
	issn = {0040-4039},
	doi = {10.1016/j.tetlet.2019.151254},
	author = {Rashid, P. P. and Singh, Dharmendra and Sanjayan, Gangadhar J.}
}
@article {49821,
	title = {Ketenimine multicomponent strategy for multifaceted amidine functionalization of peptides on the solid phase},
	journal = {Angewandte Chemie-International Edition},
	volume = {64},
	year = {2025},
	month = {SEP},
	type = {Article},
	abstract = {<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>
},
	keywords = {Amidines, multicomponent reactions, peptide modification, Peptide-small molecule hybrids, Solid phase peptide synthesis},
	issn = {1433-7851},
	doi = {10.1002/anie.202509854},
	author = {Bodake, Supriya Mahadev and Marelli, Udaya Kiran}
}
