- Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o -NosylOXY): A recyclable coupling reagent for racemization-free synthesis of peptide, amide, hydroxamate, and ester
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Ubiquitousness of amide and ester functionality makes coupling reactions extremely important. Although numerous coupling reagents are available, methods of preparation of the common and efficient reagents are cumbersome. Those reagents generate a substantial amount of chemical waste and lack recyclability. Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o-NosylOXY), the first member of a new generation of coupling reagents, produces byproducts that can be easily recovered and reused for the synthesis of the same reagent, making the method more environmentally friendly and cost-effective. The synthesis of amides, hydroxamates, peptides, and esters using this reagent is described. The synthesis of the difficult sequences, for example, the islet amyloid polypeptide (22-27) fragment (with a C-terminal Gly, H-Asn-Phe-Gly-Ala-Ile-Leu-Gly-NH 2) and acyl carrier protein (65-74) fragment (H-Val-Gln-Ala-Ala-Ile- Asp-Tyr-Ile-Asn-Gly-OH), following the solid-phase peptide synthesis (SPPS) protocol and Amyloid β (39-42) peptide (Boc-Val-Val-IIe-Ala-OMe), following solution-phase strategy is demonstrated. Remarkable improvement is noticed with respect to reaction time, yield, and retention of stereochemistry. A mechanistic investigation and recyclability are also described.
- Dev, Dharm,Palakurthy, Nani Babu,Thalluri, Kishore,Chandra, Jyoti,Mandal, Bhubaneswar
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p. 5420 - 5431
(2014/07/08)
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- Synthesis and biological evaluation of new potential inhibitors of N-acylethanolamine hydrolyzing acid amidase
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N-Acylethanolamines, including N-palmitoyl-ethanolamine (PEA), are hydrolyzed to the corresponding fatty acids and ethanolamine by fatty acid amide hydrolase (FAAH). Recently, N-acylethanolamine-hydrolyzing acid amidase (NAAA) was identified as being able to specifically hydrolyze PEA. In order to find selective and effective inhibitors of this enzyme, we synthesized and screened several amides, retroamides, esters, retroesters and carbamates of palmitic acid (1-21) and esters with C15 and C17 alkyl chains (22-27). Cyclopentylhexadecanoate (13) exhibited the highest inhibitory activity on NAAA (IC50 = 10.0 μM), without inhibiting FAAH up to 50 μM. Compound 13 may become a useful template to design new NAAA inhibitors.
- Saturnino, Carmela,Petrosino, Stefania,Ligresti, Alessia,Palladino, Chiara,Martino, Giovanni De,Bisogno, Tiziana,Marzo, Vincenzo Di
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supporting information; experimental part
p. 1210 - 1213
(2010/05/19)
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- the Effect of Hydrophobic-Lipophilic Interactions on Chemical Reactivity. 1. New Evidence for Intermolecular Aggregation and Self-Coiling
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The hydrolytic behavior of 21 para-substituted phenyl esters of n-alkanoic acids (n-X) with various chain lengths in 60:40 (Φ=0.60), 50:50 (Φ=0.50), and 40:60 v/v (Φ=0.40) Me2SO-H2O mixtures was studied.Four new sets of experimental results which include departure from Hammett correlation for N-hexadecanoates (16-X), substantial differences in activation parameters, and effects of amylose on the kinetic parameters and on the activation parameters are presented along lines of reasoning mentioned by previous authors.These data establish that the aggregation and self-coiling of the n-alkanoate chain actually exist under experimental conditions.
- Jiang, Xi-Kui,Hui, Yong-Zheng,Fan, Wei-Qiang
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p. 3839 - 3843
(2007/10/02)
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