63379-17-9

Upstream product

• 67-56-1 methanol 
• 201230-82-2 carbon monoxide 
• 121-14-2 2,4-dinitrotoluene 
• 79-22-1 methyl chloroformate 
• 99-55-8 2-methyl-5-nitroaniline 
• 14983-92-7 methyl N-(2-methylphenyl)carbamate 
• 924666-87-5 (2-methyl-5-nitroso-phenyl)-carbamic acid methyl ester 

Relevant academic research and scientific papers

Carbonylation of dinitrotoluene to dimethyl toluenedicarbamate; high efficiency of phosphorus acids as promoters for the palladium-phenanthroline catalytic system

Phosphorus acids are excellent promoters for the palladium-phenanthroline catalyzed carbonylation of 2,4-dinitrotoluene to 2,4-toluenedicarbamate. For the first time, all intermediate nitrocarbamates and aminocarbamates have been independently synthesized and their amount after every catalytic reaction precisely quantified. An extensive optimization of all experimental variables has been carried out. The best acids are phenylphosphonic and 4-tolylphosphonic acids. The addition of 2,2-dimethoxypropane as an internal drying agent is highly beneficial. The addition of an amine derived from the starting dinitroarene increases both rate and selectivity of the carbonylation reaction. The complexes [Pd(Phen)2] [SbF6] and [Pd(Phen) 2][BArF4] [ArF = 3,5-(CF 3)2C6H3] have been prepared for the first time. The latter displays a markedly higher solubility than all other [Pd(Phen)2]2+ complexes. The effect of several possible promoters has also been investigated. Under the optimized experimental conditions, a 77.6% selectivity in dicarbamate was obtained when working at a molar ratio dinitrotoluene/Pd = 2920. At the end of the reaction, the dicarbamate spontaneously precipitates out of the solution in high yields upon cooling, with no inclusion of the acid promoter or of phenanthroline. 2,6-Dinitrotoluene can also be efficiently carbonylated to the corresponding dicarbamate.

The palladium-phenanthroline catalyzed carbonylation of nitroarenes to diarylureas: Effect of chloride and diphenylphosphinic acid

The application of the palladium-phenanthroline catalytic system to the carbonylation of nitrobenzene in the presence of aniline to afford diphenylurea has been investigated. The reaction is best performed with equimolar amounts of the two reagents. Use of higher concentrations of either aniline or nitrobenzene or an increase in temperature in the range 120-170 °C leads to the formation of higher amounts of azo- and azoxybenzene. The latter were found to contain exclusively the aryl moiety deriving from nitrobenzene, with no inclusion of that derived from aniline. The addition of a small amount of diphenylphosphinic acid doubles the conversion and improves the selectivity in diphenylurea, but the effect is attenuated for larger amounts of acid. Small amounts of chloride, of the order of 10-30 mol% with respect to palladium, improve both rate and selectivity, but only inhibiting effects are detected when chloride is added to the reaction mixture for the carbonylation of 2,4-dinitrotoluene to dimethyl 2,4-toluenedicarbamate. The data obtained and that previously reported in the literature has been analyzed in the context of a unifying mechanism and an explanation for some apparent contradictions has been given.

Synthesis of alkyl N-(C-nitrosoaryl)carbamates and some reactions thereof

Reactions of alkyl N-phenylcarbamates, m-di(methoxycarboxyamido)benzene, and methyl N-(o-tolyl)carbamate with nitrosylsulfuric acid in glacial acetic acid afford N-(C-nitrosoaryl)carbamates; under these conditions tert-bulyl N-phenylcarbamate suffers decarboxylation, methyl N-(p-tolyl)-, methyl N-(p-methoxyphenyl)carbamates, o-and p-di(methoxycarboxyamido)benzenes are nitrated, and isomeric methyl N-nitrophenylcarbamates and methyl N-(p-bromophenyl)carbamate do not react. The reduction of N-(C-nitrosoaryl)carbamates with dithionite afforded the corresponding aminocarbamates; the oxidation with nitric acid yielded carbamate nitro derivatives; the condensation with aniline and benzylpyridinium chloride resulted in carbamate derivatives of azobenzene and phenylnitron.

Reductive carbonylation of aromatic dinitro compounds with a palladium(phenanthroline)2(triflate)2 catalyst and an aromatic carboxylic acid as cocatalyst

Reductive carbonylation of aromatic dinitro compounds to afford valuable dicarbamates proceeds at reasonable rates and with high selectivities under the influence of a Pd(phenanthroline)2(triflate)2 catalyst in combination with an aromatic carboxylic acid as cocatalyst.