METAL CYANATES

The nitrogen of aHphatic and aromatic amines is alkylated rapidly by alkyl sulfates yielding the usual mixtures. Most tertiary amines and nitrogen heterocycles are converted to quaternary ammonium salts, unless the nitrogen is of very low basicity, eg, ia tn phenylamine. The position of dimethyl sulfate-produced methylation of several heterocycles with more than one heteroatom has been examined (22). Acyl cyanamides can be methylated (23). Metal cyanates are converted to methyl isocyanate or ethyl isocyanate ia high yields by heating the mixtures (24,25). 

Carbamyl and thiocarbamyl fluorides are obtained from hydrogen fluoride and cyanic acid or alkali metal cyanates or thiocyanates [/, 54] Nitnles give iraidofluoride salts with hydrogen fluoride [7] whereas hydrogen cyanide affords difluoromethylamine, which can be isolated as its hexafluoroarsinate salt [55) (equation II)... 

Alkali metal cyanates are stable and readily obtained by mild oxidation of aqueous cyanide solutions using oxides of or Ptf. The commercial preparation of NaNCO is by reaction of urea with Na2C03. 

See other GOLD COMPOUNDS See related METAL CYANATES... 

The rate of exothermic hydrolysis becomes dangerously fast above 80°C. See related cyano compounds, metal cyanates... 

See related alkylmetals, metal cyanates See other /V-metai, derivatives... 

Cyclization of an ot-hydroxy ester with a metal cyanate is also a useful approach... 

Surprisingly it was reported that when potassium cyanate is substituted for sodium cyanate the yields of carbamates are reduced to less than 5 %. The reason for this drastic effect is not known at this time. In addition, the use of other alkali or alkaline metal cyanates in this reaction has not been investigated. The Loev [28] procedure appears applicable to the synthesis of carbamates from primary, secondary, and tertiary alcohols (2 hr reaction time affords 60-90% yields), cyclic and acyclic 1,3-diols, phenols, oximes, ald-oximes, and ketoximes, and primary, secondary, and tertiary mercaptans. Carbamates could not be obtained from diphenylethylcarbinol (dehydrated to 1,1-diphenylethylene) or trichloro- and trifluoromethylcarbinols. 

Only one structure for a transition metal cyanate complex has been reported. In trigonal-bipyramidal Co(terpy)(NCO)2 (98)277 the cyanate ligand is terminal N-bonded. Based on the M—N—C bond angle (160.9°) an M—N(CO) bond distance of about 1.16 A is expected whereas a much shorter bond is found. 

N-Arylureas are obtained when salts of primary aromatic amines react with solutions of alkali metal cyanates. The process involves the rearrangement of an amine cyanate, and is analogous to Wohlers classical synthesis of urea from ammonium cyanate. 

Bailar, 1973, Vol. 3, 1288 It explodes on heating or impact. See related METAL CYANATES... 

Tetramethylammonium azidocyanatoiodate(I) [68574-15-2] i ° J--C -. , N N=N=N See Tetramethylammonium azidocyanoiodate(I), above See related METAL AZIDES, METAL CYANATES c5h12in5o... 

Metal abietates, 208 Metal acetylides, 208 Metal alkoxides, 211 Metal amidosulfates, 212 Metal azide halides, 212 Metal azides, 212 Metal azotetrazolides, 214 Metal chlorates, 214 Metal cyanates, 216... 

---