Carbamyl chloride

Ketone formation can also be avoided if one of the functional acyl halogens ia phosgene is blocked. Carbamyl chlorides, readily obtained by the reaction of phosgene with ammonia or amines, are suitable reagents for the preparation of amides ia direct Friedel-Crafts acylation of aromatics. The resulting amides can be hydroly2ed to the corresponding acids (134) ... 

The practical appHcation of this reaction has been demonstrated ia the preparation of terephthaUc acid from toluene, ia which case oxidation follows hydrolysis (135). The reaction also proceeds well with substituted carbamyl chlorides such as CgH (C2H )NCOCl. 

In these reactions the active acylating agent is the carbamyl chloride, formed by the reaction of the isocyanate with hydrogen chloride (137) ... 

Ammonia reacts vigorously with phosgene. The products are urea, biuret, ammeUde (a polymer of urea), cyanuric acid, and sometimes cyameUde (a polymer of cyanic acid). The secondary products probably arise through the very reactive intermediate carbamyl chloride [463-72-9] NH2COCI (see... 

The most important commercial process is the reaction of MDA with an excess of phosgene to form the corresponding isocyanate, 4,4 -methylene-diphenyldiisocyanate, MDI, C H qN202- The reaction proceeds through the formation of a primary carbamyl chloride that is decomposed with heating and the removal of HQ. 

The crude residue is a mixture of -nitroaniline hydrochloride, />-nitrophenyl carbamyl chloride, /7-nitrophenyl isocyanate, and the />, -dinitrodiphenylurea. The -nitrophenyl carbamyl chloride is converted to -nitrophenyl isocyanate during recrystallization from the hot carbon tetrachloride. 

Nitrophenyl isocyanate has been prepared by heating -nitrophenyl carbamyl chloride. The latter has been obtained by the action of phosgene on -nitroaniline in benzene-toluene solutions, and by the action of phosphorus pentachloride on methyl jii-nitrophenylcarbamate. The preparation given above is based upon recent publications of the authors. ... 

Diakyl carbamyl chlorides Diakyl aluminum hydrides Diborane Dibromoketone Dichloromethyl chloroformate Diphosgene Fuming nitric acid Gngnard reagents Hydrides nonvolatile... 

Diethyl aniline, 54 Diethylcarbaniazine citrate, 54 Diethyl carbamyl chloride, 54 Diethyl chlorophosphate, 54 Diethylene triamine, 54 Diethyl ether, 54 Di(2-ethylhexyl) phthalate, 54 Diethyl ketone, 54 Diethyl-p-phenylenediamine, 54 Diethyl phthalate, 54 Diethylstilbestrol, 55 Diethyl sulfate, 55 Diethyl zinc, 55 Difluoromethane chloride, 55 Digitoxin, 55 Diglycidyl ether, 55 Digoxin, 55 Diisobutyl ketone, 55 Diisopropylamine, 55 Diisopropyl ether, 55 DIKAMIN , 2,4-D, 55 DIKONIRT , 2,4-D, 55 Dimefox, 55 Dimethoate, 55 3,3 -Dimethoxybenzidine, 55 n,n-Dimethylacetamide, 56 Dimethylamine, 56 4-Dimethylaminoazobenzene, 56 Dimethylaminoethanol, 56 n,n-Dimethyl aniline, 56 7,12-Dimethylbenz[a]anthracene, 56 3,3 -Dimethylbenzidine, 56... 

Chlorkohlen-oxyd, n. carbonyl chloride, -oxyd-ather, m. ethyl chloroformate. -saure, /. chlorocarbonic acid (chloroformic acid, CICOOH). -sMureamtd, n. chlorocarbonyl amide (carbamyl chloride, H2NCOCI). -stoff, m. carbon chloride, carbon tetrachloride (sometimes with the adj. vierfach). 

Hlasta and Deng have developed a two-step solid-phase method for the decoration of azoles at C-2 [188]. First, imidazole was loaded onto a polystyrene-bound carbamyl chloride via a benzaldehyde bridge (Fig. 40). The 2-substi-tuted imidazole was efficiently cleaved in good yields in the presence of various nucleophiles (i.e., water, alcohols, and amines), trifluoroacetic acid, and boron trifluoride under microwave irradiation in a closed vessel at 120 °C for 5 min. 

Mesitoic acid has been prepared by carbonation of mesityl-magnesium bromide 2-4 by hydrolysis of its amide prepared by condensation of mesitylene with carbamyl chloride under the influence of aluminum chloride 6 by oxidation of isodurene with dilute nitric acid 6-7 by distillation of 2,4,6-trimethylmandelic acid (low yield) 8 by dry distillation of 2,4,6-trimethyIphenyl-glyoxylic acid 9 by oxidation of the latter with potassium permanganate 10 and by treating 2,4,6-trimethylphenylglyoxylic acid with concentrated sulfuric acid in the cold11 or with heating.12... 

Carbamate herbicides, 13 320 Carbamates, 13 108 amine, 16 359 Carbamic acid nitrile, 3 158 Carbamide derivatives, as cellulose solvents, 11 272 Carbamodiimide, 8 158 Carbamoylated gelatin, 12 444 Carbamoyl-methylphosphoryl family, extractants of, 10 789 Carbamyl chlorides, 12 180 Carbanion coordination, 13 656—657 Carbanions, 21 101... 

Tert-Butyl Peroxypivalate Diethyl Carbamyl Chloride... 

Reaction of Carbamyl Chlorides and Derivatives with Hydrazines... 

Carbamates, transesteriflcation, 243 IV-Carbamates, 223-234 O-Carbamates, 235-245 Carbamic acid derivatives, reactions to give semicar bazides, 198-199 Carbamoyl chloride, 244 Carbamyl chlorides, 198-200 Carbanilide, see jym-Diphenylurea Carbenes, 52, 62... 

Carbamyl chlorides, available by the reaction of phosgene on secondary amines, can react with hydrazines to give good yields of 1,1-dialkylsemi-carbazides [31] (Eq. 24). 

Alkyl carbamates prepared from the carbamyl chlorides also react with amines to give semicarbazides [15, 17] (Eq. 25). 

Examples of the products of the reaction of carbamyl chlorides and derivatives with hydrazines are listed in Table VIII. 

The hydrolysis of alkyl chloroformates and carbamyl chlorides are two special cases of interest. 

Bohme and Schiirhoff131 have measured the rate of hydrolysis of ethyl chloroformate and found it to be quite slow (kx = 2.0x 10"4sec-1 in water at 25°C). Hall118, investigating the hydrolysis of ethyl chloroformate and dimethyl carbamyl chloride, found the rate sequence for neutral hydrolysis to be... 

Queen153 has recently measured the activation parameters A//, A5 and ACp for the hydrolyses of Me, Et, /z-Pr, /-Pr, and phenyl chloroformates and dimethyl carbamyl chloride in pure water (Table 22), and concluded that a change of mechanism (SN2 to SN1) takes place with increasing electron donation to the chlorocarbamyl group the data, which include solvent isotope effects, are consistent with a unimolecular hydrolysis of isopropyl chloro-formate and dimethyl carbamyl chloride and a bimolecular hydrolysis of the other four compounds. 

Mesitoic acid has been obtained by hydrolysis of its amide which was prepared from mesitylene, carbamyl chloride, and aluminum chloride in carbon disulfide.1 It has been prepared by heating isodurene with dilute nitric acid,2,3 in small yields by the distillation of 2,4,6,-trimethylmandelic acid,4 by dry dis-... 

---