Ethyl N-benzylcarbamate

Ethylamine, 2-chloro-N,N-dimethyl-, HYDROCHLORIDE, 31, 37 N-methyl-1,2-diphenyl-, 34, 64 N-Ethylaniline, 36, 22 Ethyl benzalmalonate, 37, 5 Ethyl benzoylacetate, 32, 85 37, 3 Ethyl benzoylacetate, 37, 32 Ethyl N-benzylcarbamate, 35, 91 Ethyl 3-benzyl-2-cyano-3-methylpenta-noate, 35, 7... 

A. Ethyl N-benzylcarbamate. A 12-1. three-necked flask fitted with a sturdy Hershberg-type stirrer and two 1-1. addition funnels is immersed in an ice bath and charged with 1 kg. (9.33 moles) of benzylamine, 500 ml. of ice water, and 1.5 kg. of chopped ice. To the stirred mixture 525 g. (4.83 moles) of ethyl chlorocar-bonate is added dropwise while the temperature is maintained at 10-15° (1.0-1.5 hours) (Note 1). An additional 500 ml. of water and 1 kg. of chopped ice are then added to the flask, and a second 525-g. portion (4.83 moles) of ethyl chlorocarbonate is introduced. Simultaneously with this, an ice-cold solution of 400 g. (10 moles) of sodium hydroxide in 1.3 1. of water is added dropwise at such a rate that equal fractions of the ethyl chlorocarbonate and sodium hydroxide solutions are introduced over equal periods of time, the temperature being maintained throughout at 10-15° (2.5-3.0 hours). The reaction mixture is stirred for an additional 30 minutes and is then filtered through a Buchner funnel. The solid product is washed with copious amounts of cold water and is air-dried to yield 1.6 kg. (96%) of glistening while crystals, m.p. 45-47°. 

B. Ethyl N-nitroso-N-benzylcarbamate (Note 2). In a 12-1. three-necked flask fitted with a thermometer, a 2-1. addition funnel (Note 3), and a gas outlet tube are placed a solution of 360 g. (2.0 moles) of ethyl N-benzylcarbamate in 2 1. of ether and a solution of 1.2 kg. (17.4 moles) of sodium nitrite in 2 1. of water. A stirrer is not used. The reaction mixture is cooled by means of a water bath to 20° and treated with a solution of 1 1. each of concentrated nitric acid and water, contained in the addition funnel. Enough of this solution is added to impart a permanent green color to the aqueous layer, and the remainder is then added over a period of 5 hours at such a rate as to keep the aqueous phase green (Note 4) and the temperature at 25-30°. The reaction mixture is allowed to stand an additional 30 minutes, and the layers are separated. The ether layer is washed with 200-ml. portions of 10% potassium carbonate solution (Note 5) until the evolution of gas ceases and is then dried over anhydrous potassium carbonate. The ether is removed under vacuum on a water bath kept below 50° (Note 6), a residue of 400-415 g. (95-100%) of a bright orange oil (Note 7) being left. 

During this time ethyl N-benzylcarbamate begins to separate from solution as a white solid. 

Ethyl N-benzylcarbamate and its nitroso compound have been prepared by methods similar to those described for ethyl N-methylcarbamate and its nitroso compound.2 3 2-Phenylcyclo-heptanone has been prepared by the reaction of ethyl N-nitroso-N-benzylcarbamate4 with cyclohexanone,5 by the reaction of phenyldiazomethane with cyclohexanone,6 by the reaction of ethyl N-nitroso-N-methyl carbamate with 2-phenylcyclohexa-none,6 and by the rearrangement of l-phenyl-2-cyclohexylethylene oxide.7... 

N-Ethylbenzisoxazolium fluoroborate, 364 Ethyl benzoate, 296, 585, 1069 Ethyl benzoyl formate, 993,1048 Ethyl a-benzoylisobutyrate, 1258,1259 Ethyl N-benzylcarbamate, 1097 Ethyl bromide, 374, 861 Ethyl bromoaeetate, 303 Ethyl a-bromobutyrate, 298 Ethyl 2-bromo-2-methylcyclopropanecar-boxylate, 1078... 

Ring expansion. An example of the Tiffeneau rearrangement is the conversion of 1-aminomethylcyclohexanol into cycloheptanone. Gutsche found that 2-phenylcycloheptanone can be prepared by conversion of ethyl N-benzylcarbamate HO., CH2NHj... 

METHYL-, HYDROCHLORIDE, 31, 37 N-methyl-1,2-diphenyl-, 34, 64 Ethyl benzoylacetate, 32, 85 Ethyl N-benzylcarbamate, 35, 91... 

Ethyl-N-benzylcarbamate also gave a broad ESR signal without hyper-fine structures, indicating that the strong delocalization of the unpaired electron could take place along the conjugated benzene ring. 

Ethyl N-nitroso-N-benzylcarbamate is heat sensitive and, if the temperature is too high, may detonate violently. The submitters state that attempts to distil the nitroso compound under high vacuum have resulted in explosions. 

Phenyldiazomethane has been prepared by reaction of base with ethyl N-nitroso-N-benzylcarbamate, N-nitroso-N-benzylurea and N-nitroso-N-benzyl-... 

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