Cyanic acid esters reactions

D-Triazoles have been isolated from the reaction of several activated nitriles, such as cyanogen, cyanogen halides, methyl cyanoformate, and cyanic acid esters, with diazoalkanes. The reaction can formally be regarded as a 1,3-dipolar cycloaddition. The v-triazoles may be... 

Martin, D., and Niclas, H.-J., Cyanic acid esters. Part 11. Reactions of bromocyanogen and cyanic acid aryl esters with carbanion-active phosphorus compounds, Chem. Ber, 100, 187, 1967. 

To several known methods for the conversion of aldehydes into nitriles two convenient new ones have been added Cyanic acid esters, believed to be inaccessible, have been prepared in more than one way and excellent yields Their reactions have now been investigated extensively Simple methods for the preparation of diazo compounds by pyrolysis of salts of tosylhydra-zones have been found. The tosylhydrazones as well as the diazo... 

Ethonam (99), an imidazole derivative with a very different substitution pattern, is also reported to possess antifungal activity. To prepare it, alkylation of aminotetralin 94 with methylchloro-acetate gives the glycine derivative 95. Heating with formic acid then affords the amide 96 this compound is then reacted with ethyl formate to yield hydroxymethylene ester 97. Reaction with isothio-cyanic acid gives the imidazole-2-thiol 98. (The... 

Wohler s synthesis of urea by which a product of the living cell was first prepared artificially more than a century ago is the prototype of many addition reactions which take place with the reactive molecules of cyanic acid and its esters, as well as with the series of analogous thio-compounds. In these reactions NH3 is added to the C = N double bond ... 

The esters of carbamic acid, the urethanes, which are formed by combination of alcohols with compounds of the cyanic acid series, are stable substances. The reaction by which they are formed is, likewise, capable of undergoing many variations. It may be recalled that a second method of synthesising them consists in acting on the esters of chloroformic acid with ammonia and amines. 

Reaction of semicarbazides with aryl esters of cyanic acid to give semi-carbamid-carbamic acid esters [80]. 

A benzo derivative of l,2-dihydro-2,4,l-diazaborine (131) is known. Thus reaction of 2-aminobenzeneboronic acid with cyanic acid gave compound (146). Some non-hydroxyl-ated compounds were prepared from (V,(V -diphenylamidines and trialkylboranes or the n-butyl ester of diphenylborinic acid (Scheme 28) (79IZV174). 

Aryl cyanates (cyanic esters), which can be prepared in situ (67AG(E)206), form 1,3,5-triazines under either acid or base catalysis (Scheme 83) (77RCR278, 78RCR975). The acid-catalyzed reactions are not properly understood, but it seems that the mechanism is dependent on the precise nature of the Lewis acid used. Yields are usually good (Table 14). The reaction of aryl cyanates with ketoximines yields 1,3,5-triazines (146) via the intermediate (145) (Scheme 84) (66CB2361). Alkyl cyanates are very reactive, and isomerize readily therefore they are unsuitable starting materials for 1,3,5-triazine synthesis. 

In water and in. hydrophilic solvents nitrourea dearranges rapidly into cyanic acid and nitroamide. Alkalis promote the reaction. If an aqueous solution of nitrourea is warmed, bubbles of nitrous oxide begin to come off at about 60°. If it is allowed to stand over night at room temperature, the nitrourea disappears completely and the liquid is found to be a solution of cyanic acid. Indeed, nitrourea is equivalent to cyanic acid for purposes of synthesis. It reacts with alcohols to form carbamic esters (urethanes) and with primary and second amines to form mono-and unsym-di-substituted ureas. 

Chromium trioxide, 60, 21 Clemmensen reaction, 60, 111 Copper chloride (CuCl) [7758-89-6], 61, 122 Crotonic acid, ethyl ester, ( )-, 61, 85 18-Crown-6-potassium cyanide complex, 60,129 Crum Brown-Walker reaction, 60, 4 Cuprous chloride, 60, 42, 121 61, 122 CYANIC ACID, PHENYL ESTER [1122-85-6], 61, 35... 

Reaction of 1,2-diaminoarenes with phosgene or urea gives 2-benz-imida/.olones (Scheme 3.1.14). The latter reagent has been preferred as it is less toxic. There are, however, a variety of other reagents which lead to the same products carbonate esters [117], diethyl pyrocarbonatc [118], N,N-diethylcarburnyl chloride [119], l,T-carbonyldiimidazole [120], cyanic acid [121] and carbon dioxide [122]. (See also reactions with ketones below.) Preston has reviewed these processes [54]. The reactions with urea (or... 

Cyanuric Acid.—That iso-cyanic acid has the constitution given to it is established by the constitution of the alkyl derivatives which are not true esters (p. 73) and also by its relation to cyanuric acid. This latter acid is a polymer of iso-cyanic acid, viz., (HNCO)3. It is obtained by heating urea and the reactions will be considered presently when we study this compound. This source of the acid is the basis of the name cyan-uric acid. It is a solid crystallizing from water solution in prisms which contain two molecules of water of crystallization. Like iso-cyanic acid cyanuric acid yields alkyl derivatives of two isomeric forms, corresponding to polymers of cyanic and iso-cyanic acid derivatives. The ethyl derivatives have the following constitutions ... 

There is similar ready reaction of hydrazines with salts or esters of cyanic acid, under conditions similar to those required by amines. Hydrazine itself is in most cases substituted on both nitrogen atoms alkylhydrazines usually react at the -nitrogen atom but arylhydrazines at the -nitrogen atom.74... 

Any processes that can lead to the formation or disappearance of phase-separated or homogeneously mixed binary SAMs can be monitored through the change in the desorption peak in voltammo-grams. Figme 16 shows an example of detecting the rate of a surface chemical reaction using the shift in Ep. When iso-cyanic acid n-butyl ester in toluene reacted... 

The reaction of cyanic esters with sodium thiosulfate in acid solution occurs particularly readily. 

Reaction with cyanic esters 732 Carbon disulfide (2.28 g, 30 mmoles) in ether (5 ml) is dropped into a solution of the amine (30 mmoles) and triethylamine (3.03 g, 30 mmoles) in ether (20 ml) which is stirred and cooled in ice-water. The mixture is then left at room temperature for 1 h (or 24 h for aromatic amines), treated with phenyl cyanate (3.57 g, 30 mmoles), and diluted with ether (5 ml). The clear solution that results is extracted with dilute hydrochloric acid, with sodium hydrogen carbonate solution, and with water, concentrated, filtered from the precipitated phenyl thiocarbamate, and fractionated. Yields are about 60%. 

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