N- carbamates

NHjCOOCHj) Ethyl carbamate (urethane) n-Propyl carbamate. n-Butyl carbamnte n-Amyl carbamate t o-Amyl carbamate. N-Methylurethane... 

PREPARATION OF N-ARYL-5R-HYDROXYMETHYL-2-OXAZOLIDINONES FROM N-ARYL CARBAMATES N-PHENYL-(5R)-HYDROXYMETHYL- 2-OXAZOLIDINONE... 

Oxidative carbonylation generates a number of important compounds and materials such as ureas, carbamates, 2-oxazolidinones, and aromatic polycarbonates. The [CuX(IPr)] complexes 38-X (X = Cl, Br, I) were tested as catalysts for the oxidative carbonylation of amino alcohols by Xia and co-workers [43]. Complex 38-1 is the first catalyst to selectively prepare ureas, carbamates, and 2-oxazolidinones without any additives. The important findings were the identity of the counterion and that the presence of the NHC ligand influenced the conversions. 2-Oxazohdinones were formed from primary amino alcohols in 86-96% yield. Complex 38-1 also catalysed the oxidative carbonylation of primary amines to ureas and carbamates. n-Propylamine, n-butylamine, and t-butylamine were transformed into the... 

Carbon tetrachloride Chloroform Dichloromethane 1,2-Dichloropropane Ethylene dibromide Ethylene dichloride Ethyl carbamate N-Nitrosodimethylamine Styrene... 

In contrast to the carbamates, N-tosyl carbamates 18 reacted fast (1-2 h) with LiBr in the presence of copper(II)-oxygen and catalytic amounts of palladium acetate yielding oxazolidinones 19 (Scheme 17.10). The rate enhancement is due to the presence of two electron-withdrawing substituents on nitrogen and is, again, responsible for the diminished diastereoselectivity of the reaction. Attempts to prepare the homologous six-membered heterocycles gave only poor yields. 

Polymer Structure. The reaction studied here is summarized in Equation 21. As shown in the experimental section, it is possible to prepare these polymers at various degrees of substitution. As the degree of substitution increases, the ratios of the infrared C=0/0H absorption peaks and the phenyl/aliphatic C-H absorption peaks increase in a linear manner (Table I). (It would be possible to determine the degree of substitution from such calibrated curves.) At the same time, the intensity of the OH band in the NMR spectra diminishes while a strong set of peaks due to the phenyl group forms. Elemental nitrogen analysis values for the modified polymers agree closely with the calculated values. In addition, the infrared spectra show the necessary carbamate N-H bands. These factors enable us to have confidence that the polymer structure is as shown in Equation 21. 

Abbreviated name for = Li derivative LiBTOC (A -lithio r-butyl iV-(tosyloxy) carbamate [N-lithio iV-(r-butoxycarbonyl) 0-tosylhydroxylamine]. 

N-Acyl or N-alkoxycarbonyl amidines or guanidines can be deprotonated and then alkylated [120]. The scope and limitations of these reactions are similar to those of the N-alkylation of amides or carbamates. N,N -Bis(tert-butyloxycarbonyl)guan-idine is sufficiently acidic to undergo clean N-alkylation under the conditions of the Mitsunobu reaction [121]. 

The multiplicity of abiotic transformation products which have been detected for aminocarb has prompted a comparison of the anticholinesterase activity, in vivo insect toxicity and relative volatility of a series of oxidation products. Successive oxidations of the aryldimethylamino group resulted in increased toxicity whereas oxidation of the arylmethyl group or of the carbamate N-methyl group considerably reduced toxicity. Saturated vapour concentrations of the toxic transformation products were only slightly lower than the parent carbamate. 

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