Cyanate anion

Reaction of the starting cycloadducts 5 with potassium /cri-butoxide leads to pyridines 6, probably via the diazocinedione dianion, which eliminates cyanate anion via an alternative bicyclic tautomer (cf. Houben-Weyl, Vol. E7b, p 514). 

Isocyanate and isothiocyanate carbon nuclei resonate between 120 and 130 ppm [77a]. Isothiocyanate carbons are slightly deshielded relative to comparable isocyanates. Typical nitrile shift values (110-115 ppm) are characteristic of thiocyanates (rhodanides), while the carbon nuclei of rhodanide and cyanate anions shift to lower field due to significant contributions of heterocumulene-type resonance formulae. 

Ammonium cyanate is composed of an ammonium cation (NH4+) and a cyanate anion (OCN ). Show a Lewis structure for the cyanate anion. 

Heparin-like copolymers containing up to 100 units of sulfonated glucose or lactose have been prepared by polymerizing with acrylamide using arenediazonium salts with cyanate anions to form a thrombo-resistant heparinized surface. 

Cyanoxyl radicals were generated in situ by an electron-transfer reaction between cyanate anions and p-chlorobenzenediazonium cations arenediazonium salts were previously prepared in water through the diazotization reaction of p-chloroaniline. Copolymerizations were performed using the Step 2 product and acrylamide at 50°C with ClCgPLtNi BF4 /NaOCN as the initiating system. Copolymers were isolated by precipitation in a 10-fold excess of methanol and characterized. 

Due to the weak nucleophilicity of the acetate and cyanate anions, no substitution of the chlorine atoms was observed. Instead, partial rearrangement to the greater cage molecules deca[(3-chloropropyl)-silsesquioxane] and dodeca[(3-chloropropyl)-silsesquioxane] was found. 

Figure 8. The azide anion, when enclosed in the dizinc(II) cryptate [Zn2(44)]causes the quenching of the facing anthracene fragment an electron is transferred from the electron rich anion to the photoexcited spacer. Inclusion of cyanate anion does not alter fluorescence emission, due to lack of the suitable redox potential allowing electron transfer.

Most of the examples of seleniranes and telluriranes shown as the unstable intermediates in the organic synthesis are derived from oxiranes. As discussed previously in Section 1.07.6.2, seleno-cyanate anions react with epoxides at room temperature to deposit selenium via the selenirane intermediate and form the corresponding alkenes. On the other hand, triphenylphosphine selenide and trifluoroacetic acid constitute an effective and mild combination of reagents for carrying out the deoxygenation of epoxides (67) to alkenes via cyclic intermediate (68) (Scheme 12) <73CC253>. 

Cyanide — The use of H202 for cyanide detoxification is increasing. Many effluents are treated with H202at pH 9 to give cyanate anion which is subsequently hydrolysed to carbonic acid. Some effluents, which contain... 

In another example, Weinstock and Dunoff53 selectively monochloro-sulfonated 5-(3-chlorobenzyl)-5-methylhydantoin (70) followed by treatment in situ with ammonia, which gave 8-chloro-10a-methyl-10,10a-dihydro-lH-imidazo[3,4-b][l,2]benzothiazine-l,3(2ff)-dione 5,5-dioxide (71) in high yield. Basic hydrolysis of the hydantoin ring in 71 followed by loss of cyanate anion afforded 6-chloro-3-methyl-3,4-dihydro-27/-l,2-benzothiazine-3-car-boxylic acid 1,1-dioxide (72) (Eq. 16). 

The relative stereochemistry of epoxides can be inverted by eqnilibration with cyanate anion ... 

In the cyanate anion the negative charge is distributed between the... 

The matrix-isolated spectra of HNCO, DNCO, HNCS, and DNCS in the far-i.r. (10—50 cm ) and of the CNO anion in the i.r. (550— 5000 cm ) have been recorded. The acid molecules were isolated in both argon and nitrogen matrices at 13 K although no absorptions attributable to the guest molecules were observed in the nitrogen matrix, intense bands were recorded in the argon matrix. These bands are best explained by rotation of the molecule about an axis close to the axis of least inertia. Isotopically enriched cyanate anions have been prepared by direct oxidation reactions and introduced into KCl and KBr single crystals to a maximum concentration of ca. 5 wt. The i.r. spectra of the resultant cyanate ion isotopic species show that these ions are dissolved in the form of a solid solution. 

Janikowski, J., Forsyth, C., MacFarlane, D.R. and Pringle, J.M., Novel ionic liquids and plastic crystals utilizing the cyanate anion, J. Mater. Chem. 21 (48), 19219-19225 (2011). 

Ethyl carbamate in wine is formed (mostly at the end of fermentation) from urea. The intermediates of its degradation are probably cyanates and cyanic acid (HO-C=N), also known as hydrogen cyanate, which may isomerise to isocyanic acid (H-N=C=0). Iso-cyanic acid can also arise by protonation of the cyanate anion and nucleophilic addition of ethanol to isocyanic acid yields ethyl carbamate. Isocyanic acid also reacts with other nucleophilic reagents, such as water (with formation of ammonia and carbon dioxide), thiols and amino groups of proteins. By catalysis with ornithinecar-bamoyl transferase, citrulline is transformed into ornithine and carbamoyl phosphate, the ethanolysis of which yields ethyl carbamate (Figure 12.39). 

Isocyanic acid can be made by protonation of the cyanate anion, such as from salts like potassium cyanate, by either gaseous hydrogen chloride or acids such as oxalic acid. 

A new series [32] of electron transfer initiators has been shown to give rise to long-lived oxygen-centered radical species attached to propagating acrylate and methacrylate chain ends. The long-lived nature of these chain ends makes it possible to prepare block copolymers in some cases. The oxygen-centered radical species are generated from hyponitrite, arenediazoate, or cyanate anions by reaction with electron acceptors such as arenediazonium ions or activated alkyl halides. 

Kornblum [33] showed that suitably activated alkyl halides undergo facile electron transfer when reacted with anions such as (CH3)2C(N02), CgHsS, N3, and l-methyl-2-naphathoxide. /V-Halosuccinimides also react with arenediazoate, hyponitrite, or cyanate anions in the presence of monomer to initiate polymerization, presumably in analogy to the reactions using arenediazonium ions ... 

The second method involves one-electron oxidation of arenediazoate, hyponitrite, or cyanate anions by reaction with arenediazoazodiazonium ions. Aryl radicals then initiate polymerization [32] of the monomer/methyl methacrylate, and the corresponding stabilized oxyl radical is associated with the growing end of the poljrmer ... 

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