Isocyanate, chlorocarbonyl-, reaction with

I.3.4.2.4. Heterocumulenes The 1,3-dipolar cycloaddition of substituted ben-zonitrile oxides to the C=N group of chlorocarbonyl isocyanate C1C(0)N=C=0 gives 3-aryl-4-chlorocarbonyl-5-oxo-4,5-dihydro-l,2,4-oxadiazoles 172 in 75%-80% yield (340). A similar reaction with chlorosulfonyl isocyanate, C1S02N=C=0, affords 4-unsubstituted oxadiazolinones 173 (341). 

Cyclic 1 1 and 1 2 adducts are also obtained frombis(trimethylsilyl)carbodiimide and ben-zenesulfonyl isocyanate. However, reaction of the same carbodiimide with chlorocarbonyl isocyanate affords the triazine derivative 44. ... 

Reaction of pristinamycin 11 with N-chlorocarbonyl reagents proceeded in a similar manner to the reaction with ethyl malonyl chloride, for example reaction with N-(chIorocarbonyl)isocyanate afforded after acidic work-up the carbamate (50, R = NH2) and reaction with iV-methylpiperazinylcarbonyl... 

Reactions with N-(chlorocarbonyl)isocyanate a-Chloro-N-carbonylureas from azomethines... 

A simple approach to the 2-azaallenium ions 361, based on the reaction of carbonyl compounds with chlorocarbonyl isocyanates 360, was described152. No mechanism for this reaction was suggested, but the scheme displayed in equation 101 can apply based on the considerations stated above86. 

Reaction of l-(trimethylsilyl)pyrazole with chlorocarbonyl isocyanate gives 1-oxo-l/f-pyrazolo[l,2-a][l,2,4]triazol-4-ium-3-olates <88CB895>. Another interesting reaction of the same compound is with jV-fluoropyridinium fluoride to afford 2-(pyrazol-l-yl)pyridine (24), a useful chelating agent (see Section 3.01.5.3.4(v)) <93JOC4476>. 

Triazinethiones (169) are synthesized from 5-alkylisothioureas and acyl isothiocyanates <87MI 612-04, 91PS(62)275>. A-Aminotriazinedione derivatives (170) are obtained when 5-alkyl-isothiosemicarbazones are condensed with diphenyl dicarbimidate (Scheme 51). The dicarbimidate was produced by reaction of chlorocarbonyl isocyanate with phenol <84GEP3409065>. 

Whereas direct reaction of 3,4,5-trimethyl pyrazole with chlorocarbonyl isocyanate is unsuccessful <77AG789>, treatment of its activated trimethylsilyl derivative (302) with this 1,3-bielectrophile, followed by heating, yields (303) in 35% yield (Equation (43)) <83H(20)23>. 

Reaction of A -substituted thioamides (391) with chlorocarbonyl isocyanate at room temperature affords good yields of 1-imino derivative (392) which can be quantitatively A -methylated with diazomethane to (393) (Scheme 82) <848771 >. 

For preparation of compound 193, carbamoylation of 177 by three general methods was smdied extensively (i) the reaction of 177 with isocyanates (Method 1), (ii) the reaction of l-chlorocarbonyl-5-fluorouracil 194 with amines (Method 2), and (iii) the reaction of 177 with carbamoyl chlorides (Method 3). These three methods usually give l-carbamoyl-5-fluoruracils 195 (Scheme 12.34). 3-Carbamoyl-5-fluorouracils are not formed in these reactions. 

The synthesis of cyanurates 215 started with condensation of the corresponding amines with an excess of nitrobiuret 214 (method A, Scheme 33). Subsequent ring closure with diethyl carbonate and sodium ethoxide gave compound 215 in good yields. Similar results could be obtained by the reaction of the same amines with A -chlorocarbonyl isocyanate (method B, Scheme 33) <2002CEJ2288>. 

Reaction of resin-bound amino acids 239 with isocyanates yields resin-bound ureas, which react further with chlorocarbonyl isocyanate to afford the resin-bound 1,3-disubstituted l,3,5-triazine-2,4,6-triones 240, selectively (Scheme 37). Subsequent, selective alkylation at the N-5 position, to yield the resin-bound 1,3-disubstituted... 

Also, aliphatic isocyanates react with chlorocarbonyl isocyanate to give the [4+2] cycloadducts. The reaction of carbonyl isocyanates with silylketenes affords unstable [4+2]... 

In the reaction of chlorocarbonyl isocyanate with secondary amines, allophanoyl chlorides are formed, which are readily dehydrochlorinated to give dialkylaminocarbonyl isocyanate, which dimerizes by a [4+2] cycloaddition reaction to give 481 ". ... 

Small molecules with novel combinations of functional groups sudi as N-(a-chlorobenzylidene)carbamoyl chloride S tosylmethyl isocyanide N-(chlorocarbonyl) isocyanate , or triphenyl(prop-2-ynyl)phosphonium bromide have each become the source of a variety of old and new compounds, mostly heterocyclics. By an anomalous reaction, tosylmethyl isocyanide converts adamantane into 2-cyanoadamantane in high yield . 

Thiazolo [3,2-c]pyrimidine-5,7-diones 123 (Ri = R2 = Rs= H, CH3 R4 = H, CH3) were prepared by reaction of N-(chlorocarbonyl) isocyanate with 2-alkylthiazolines 122 (Scheme 54) in acetonitrile containing triethyl amine [80],... 

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