Zinc promoted simple and convenient synthesis of carbamates: An easy access for amino group protection

Yadav, J. S.; Reddy, Gondi Sudershan; Reddy, M. Muralidhar; Meshram, H. M.

doi:10.1016/s0040-4039(98)00464-x

Cited by 60 publications

(34 citation statements)

References 11 publications

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“…(3)], following a protocol already shown in the literature to give good results for the synthesis of carbamates in which the aryl group bears electron-withdrawing substituents. [36] ð3Þ Reaction of 5 with methyl chloroformate in the presence of ZnCl 2 and triethylamine gave 3a almost exclusively [Eq. (4)] and the pure product could be isolated by crystallization free of any 3b.…”

Section: Independent Synthesis Of the Organic Intermediates Or Byprodmentioning

confidence: 99%

Carbonylation of Dinitrotoluene to Dimethyl Toluenedicarbamate; High Efficiency of Phosphorus Acids as Promoters for the Palladium-Phenanthroline Catalytic System

Gasperini

Ragaini

Cazzaniga

et al. 2005

Advanced Synthesis & Catalysis

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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. have been prepared for the first time. The latter displays a markedly higher solubility than all other [Pd(Phen) 2 ] 2 þ 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 ¼ 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.

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Section: Independent Synthesis Of the Organic Intermediates Or Byprodmentioning

confidence: 99%

Carbonylation of Dinitrotoluene to Dimethyl Toluenedicarbamate; High Efficiency of Phosphorus Acids as Promoters for the Palladium-Phenanthroline Catalytic System

Gasperini

Ragaini

Cazzaniga

et al. 2005

Advanced Synthesis & Catalysis

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“…Inspite of the presence of mushroom of reducing agents for the reduction of aromatic carbonyl/nitro group, even though a few researchers [12][13][14][15] used zinc for reduction, including the recently reported reduction of graphene oxide to graphene by metal mediated direct electron transfer reduction [16][17][18][19] and metal mediated atomic hydrogen reduction [20,21], the feasibility of using a commonly available non-toxic reagent which can act as the reducing agent at room temperature by the nascent hydrogen generated from Zn/HCl system was only reported in earlier investigation [22] but the yield was poor.…”

Section: Introductionmentioning

confidence: 99%

Solvent Free Facile Room Temperature Reduction of Aromatic Carbonyl and Nitro Compounds by Zn/Conc. HCl System-An Experimental and DFT Study

Rajamathe¹,

Bhuvaneswari²

2018

Asian J. Chem.

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This experimental and DFT studies involve a novel technique for the reduction of aromatic carbonyl/nitro compounds to the corresponding alcohols/amines, in high yield under laboratory conditions. The reducing species is the nascent hydrogen generated by the Zn/HCl system. The novelty of this work is that the comparison of yield with and without solvent. The yield is increased by many folds in the solvent free method compared to the solvent method reported earlier. The technique followed is to make a 'slurry' of the substrate with zinc dust (zinc slurry) and to add (in small portion of the dry slurry) to the optimized amount of conc. HCl, over a period of 3 to 4 h at room temperature. In this technique the substrate, adsorbed on zinc dust being very proximal to the site of generation nascent hydrogen, the reduction is very effective and the yield is high. The novelty is that zinc dust acts as catalyst (adsorbent role) and reactant (hydrogen generation role). The DFT study with B3LYP/6.311g ++ (d,p) basis set revealed that the stability of first formed free radical (energy factor) and the homo nuclear nature of carbonyl and nitro group (charge factor) decide the yield. The electrostatic potential calculated by DFT studies correlates well with Mullikan charges in deciding the charge factor. The free radical mechanism was confirmed by the formation of pinacol coupled product in one instance.

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“…As an alternative approach, substituted chloroformates [15][16][17] are the most frequently used reagents for the preparation of organic carbonates. This reagent has gained much attention recently, because of easy handling, non-toxic nature as well as good reactivity which have led to a successful synthesis of azo organic carbonates.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Spectroscopic Investigation and Computational Studies of 2-Formyl-4-(Phenyldiazenyl)Phenyl Methyl Carbonate and 4-((4-Chlorophenyl)Diazenyl)-2-Formylphenyl Methyl Carbonate

Arokiasamy

Manikandan

Thanikachalam

et al. 2016

ILCPA

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ABSTRACT. Two new compounds namely 2-formyl-4-(phenyldiazenyl)phenyl methyl carbonate (FPMC) and 4-((4-chlorophenyl) diazenyl)-2-formylphenyl methyl carbonate (CFPMC) have been synthesized and have characterized using FT-IR, FT-Raman, 1 H and 13 C NMR techniques. Computational optimization studies have been carried out using Hatree-Fock (HF) and Density Functional Theory (DFT-B3LYP) methods with 6-31+G(d, p) basis set of Gaussian 09W software. The stable configuration of the title compounds were achieved theoretically by potential energy surface scan analysis. The complete vibrational assignments were performed on the basis of total energy distribution (TED) and natural bonding orbital (NBO) have been studied. Various parameters such as E HOMO , E LUMO , total energy, dipole moment, polarizability, first order hyperpolarizability, zero-point vibrational energy as well as thermal properties were analyzed and reported for the title compounds.

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Zinc promoted simple and convenient synthesis of carbamates: An easy access for amino group protection

Cited by 60 publications

References 11 publications

Carbonylation of Dinitrotoluene to Dimethyl Toluenedicarbamate; High Efficiency of Phosphorus Acids as Promoters for the Palladium-Phenanthroline Catalytic System

Carbonylation of Dinitrotoluene to Dimethyl Toluenedicarbamate; High Efficiency of Phosphorus Acids as Promoters for the Palladium-Phenanthroline Catalytic System

Solvent Free Facile Room Temperature Reduction of Aromatic Carbonyl and Nitro Compounds by Zn/Conc. HCl System-An Experimental and DFT Study

Synthesis, Spectroscopic Investigation and Computational Studies of 2-Formyl-4-(Phenyldiazenyl)Phenyl Methyl Carbonate and 4-((4-Chlorophenyl)Diazenyl)-2-Formylphenyl Methyl Carbonate

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