[reaction: see text] We report for the first time that stoichiometric and even catalytic quantities of weak acids in aqueous solution can very efficiently catalyze amide isomerization in a carefully designed system in which a proton donor is situated so that intramolecular hydrogen bonding to the amide nitrogen is highly favored. Our results provide the first experimental verification that hydr...

We used ultraviolet resonance Raman (UVRR) spectra to examine the spatial dependence and the thermodynamics of R-helix melting of an isotopically labeled R-helical, 21-residue, mainly alanine peptide. The peptide was synthesized with six natural abundance amino acids at the center and mainly perdeuterated residues elsewhere. CR deuteration of a peptide bond decouples CR-H bending from N-H bendi...

(15)NH(4) (+) and [(15)N](amide)-glutamine externally supplied to detached nodules from soybean plants (cv. Tamanishiki) were incorporated within nodule tissues by vacuum infiltration and metabolized to various nitrogen compounds during 60 minutes of incubation time. In the case of (15)NH(4) (+) - feeding, the (15)N abundance ratio was highest in the amide nitrogen of glutamine, followed by glu...

The new ligand N3Py(amide)SR and its Fe(II) complex [Fe(II)(N3Py(amide)SR)](BF4)2 (1) are described. Reaction of 1 with PhIO at -40 °C gives metastable [Fe(IV)(O)(N3Py(amide)SR)](2+) (2), containing a sulfide ligand and a single amide H-bond donor in proximity to the terminal oxo group. Direct evidence for H-bonding is seen in a structural analogue, [Fe(II)(Cl)(N3Py(amide)SR)](BF4)2 (3). Comple...

microwave-assisted three component cyclocondensation reactions of aldehydes, amides and dienophiles in the presence of acetic anhydride and para-toluenesulfonic acid as a catalyst to afford the highly substituted cyclohexene derivatives, in relatively good yields after several minutes are reported.

ab initio calculations were employed to investigate nitrogen inversion as a configuration change that can supply an infinitely useful switchable control mechanism for some complex systems. in this paper, design of a new artificial molecular nanohinge is discussed based on nitrogen inversion in which reciprocating motion of substituent in effect of inversion phenomenon, led to an open–close moti...

in this article six new copoly(amide-imide)s (11a-c) were synthesized through the directpolycondensation reaction of 1,3-bis[4,4'-(trimellitimido) phenoxy] propane (6) with 3,3'-diamino diphenyl sulfone (7), 4,4'-diaminodiphenyl ether (8) and 1,5-naphtalene (9) in thepresence of fumaric acid (10) as a second diacid in a medium consisting of n-methyl-2-pyrrolidone, triphenyl phosp...

The stability constants of the binary Cu2+ complexes of glycine amide, diglycine, diglycine amide, triglycine, and tetraglycine were determined, as were those of the mixed-ligand Cu2+ systems containing 2,2'-bipyridyl and one of the mentioned oligoglycines. The results evidence that all these complexes have the same structure and, therefore, the binding sites of the ligands have to be the termi...

Certain "degradation" products of GLP-1 were found to possess beneficial effects on metabolic homeostasis. Here, we investigated the function of the COOH-terminal fragment of GLP-1, the nonapeptide GLP-1(28-36)amide, in hepatic glucose metabolism. C57BL/6 mice fed a high-fat diet (HFD) for 13 wk were injected intraperitoneally with GLP-1(28-36)amide for 6 wk. A significant reduction in body wei...