O-cyanate

The following alternative method may be used. Dissolve 0-01 mol of the phenol and 0-01 mol of a-naphthyl t o-cyanate in 20 ml. of light petroleum (b.p. 60-80°), add 2 drops of triethylamine (or, less satisfactorily, 2 drops of pyridine), reflux for 5 minutes, and allow to crystallise. Filter ofiF the crystalline sohd through a sintered glass funnel. 

Dimethylamino)phenol, AN87 U-D i methy 1 am i nopheny1 i soth i o-cyanate, AP2U... 

In view of the foregoing situation and the uncertainties of whether or not O-cyanates do indeed exist or whether all the many A-cyanato complexes have been correctly characterized, any explanations concerning the behavior of the cyanate group would be premature. INDO calculations showed that almost equal electron densities existed at nitrogen and oxygen (383), so there is no apparent reason why both ends should not be involved in coordination. Attention has been drawn (86) to the fact that many of the metals found to form O-cyanates have vacant or only partly filled dn orbitals to interact with filled tt orbitals of the cyanate group. Whether these are centered on the oxygen or whether that atom forms the better a bond with these mostly class a metals remains to be seen. 

The classical Kolbe-Schmidt reaction treats alkali metal phenoxides and carbon dioxide at higher than atmospheric pressure, giving salicylic acid. Hirao and Kato developed several modifications for industrial production ". Recently, phenol phosphate was enzymatically carboxylated, giving p-hydroxybenzoic acid ". As for related reactions, Sartori and coworkers conducted o-carbamoylation of aluminum or boron phenoxides with alkyl isocyanate ", and Adachi and Sugasawa o-cyanated phenols using methyl thioisocyanate in the presence of BCI3 (equation 54). ... 

Some organosilicon compounds undergo transmetallation. The allylic cyanide 461 was prepared by the reaction of an allylic carbonate with trimethylsi-lyl cyanide[298]. The oriho esters and acetals of the o. d-unsaturated carbonyl compounds 462 undergo cyanation with trimefhylsilyl cyanide[95]. 

A one-step synthesis o( mtnles from carbonyls by a reductive cyanation with tosylmethyl isocyanide (TosMIC), also synthesis of 1,3-azole or of ketones... 

The 6-methyl derivative (98, R = Me) was an important intermediate in the synthesis of analogs (e.g., 183) of folic acid. Korte has shown that 2-aminopyrido[3,2-guanidine carbonate with 3-aminopicolinic acid and that treatment of the same acid with ammonium thiocyanate or potassium cyanate yields the thioureido and ureido derivatives (100, X = S and X = 0). In contrast to the pyrido[2,3-d]pyrimidine system bsoth of these compounds could be cyclized by heat and the latter (100, X = O) is a likely intermediate in the synthesis of the dione (98) by the fusion with urea. 

The mechanism of action of the cyanation reaction is considered to progress as follows an oxidative addition reaction occurs between the aryl halide and a palladium(O) species to form an arylpalladium halide complex which then undergoes a ligand exchange reaction with CuCN thus transforming to an arylpalladium cyanide. Reductive elimination of the arylpalladium cyanide then gives the aryl cyanide. 

For a monograph, see Reutov, O.A. Beletskaya, I.P. Kurts, A.L. Ambident Anions Plenum NY, 1983. For a review, see Black, T.H. Org. Prep. Proced. Int., 1989, 21, 179. Both cyanates and isocyanates have been isolated in treatment of secondary alkyl iodides with NCO Holm, A. Wentrup, C. Acta Chem. Scand., 1966, 20, 2123. 

Silver cyanate, AgNCO, consists of infinite chains of alternating Ag+ and NCO- ions. Ag+ has c.n. 2 and only one of the terminal atoms of the cyanate group is part of the chain skeleton, being coordinated to 2 Ag+. Decide with the aid of Pauling s second rule which of the cyanate atoms (N or O) is the coordinated one. (Decompose the NCO- to N3-, C4+ and O2-). 

The iV-( -nitrophcnyl)pipcrazinc-2-carbonitrilc 251 (Y = NBOC) was reductively cyclized to the tricyclic /V-oxides 252 (Y = NBOC) either by catalytic hydrogenation, or by electrochemical reduction. Electrochemical reduction gave lower yield. Compounds 251 were prepared by electrochemical cyanation of the iV-(o-nitrophenyl)piperazine 250. The jV-oxides 252 were further hydrogenated to the 2,3,4,4 ,5,6-hexahydro-l//-pyrazino[l,2- ]quinoxaline 253 (Y = NBOC) (Scheme 46) <2001EJ0987>. 

Having the same atomic composition as cyanates but drastically different properties are the fulminates, which contain CNO-. Many organic compounds having the formula R-N-C-O are known (the isocyanates). Cyanides undergo an addition reaction with sulfur to produce thiocyanates. 

Recently, the solvolyses of l-chloro-l,3,3-triarylallenes 10 (andof 1-butyl-3,3-diphenyl-allenyl chloride) were carried out in the presence of thiocyanate and o-ethyl dithiocar-bonate anions as nucleophiles and found to give the corresponding allenyl derivatives 11 and 12 in good yield (equation 3)18. However, when potassium cyanate was used as a nucleophile, the cyanate ion attacked at the /-position to give the propargyl amines 14 after decarboxylation of the unstable intermediate 13 (equation 4). 

The photocyanation of 2-nitrothiophene in KCN solution in water (see page 241) shows not only a normal increase of with increasing [CN ] but also the quantum yield of its consumption equals that of the formation of 2-cyanothiophene. With 2-nitrofuran under similar conditions the 4> value for formation of 2-cyanofuran again increases in the usueiI way with increase of [CN ], levelling off at a limiting value of 0-51 at [CN ] O l m. However, the quantum yield of disappearance of the nitrofuran is 0 51, independent of the cyanide concentration. Evidently, there is a second photoreaction (with water) that complements the cyanation. Indeed 7-butenoIide could be found as a product of irradiation of 2-nitrofuran in water. 

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