20-02-1957 дата публикации
Номер: GB768770A
Автор:
The invention comprises esters of the general formula <FORM:0768770/IV(b)/1> wherein n is an integer from 1 to 6 inclusive and R is a tertiary amino radical, and acid addition and quaternary ammonium salts thereof; and their preparation by esterifying a 2,6 - dimethyl - 4 - carbomethoxybenzoyl halide with a tertiary alkanolamine, ammonolysing the so-formed tertiary aminoalkyl ester of 2,6-dimethyl-4-carbomethoxy-benzoic acid to give a tertiary aminoalkyl 2,6-dimethyl-4-carbamoylbenzoat and subjecting this to a Hofmann degredation to the corresponding amine. Tertiary alkanolamines which may be used include dialkylamino-, dicycloalkylamino-, alkylaralkylamino- and diaralkylamino-alkanols and heterocyclicamino-alkanols such as 1-pyrolidyl-, piperidino- and morpholino-alkanols and alkyl-substituted homologues thereof. The Hofmann degradation, which is generally effected by dissolving the amide in a very slight excess of cold aqueous alkali-metal hypohalite solution followed by rapid warming, is advantageously modified by carrying out the reaction in an alcoholic solution with subsequent hydrolysis of the intermediate so obtained. Salt forming acids referred to are hydrochloric, hydrobromic, sulphuric, acetic, lactic, tartaric, succinic, benzoic, salicylic and picric acids. Quaternary ammonium salt-forming compounds referred to include alkyl halides, aralkyl halides and alkyl esters of aryl sulphonic acids. Examples describe the preparation of (1) b -diethyl aminoethyl-2,6-dimethyl-4-aminobenzoate via the intermediates diethylaminoethyl 2,6 - dimethyl - 4 - carbomethoxybenzoate, b - diethylaminoethyl 2,6 - dimethyl-4 - carbamoyl benzoate and b - diethylaminoethyl 2,6 - dimethyl - 4 - carbomethoxyaminobenzoate, the latter being hydrolysed with aqueous sodium hydroxide to the required product, which is converted to its methochloride, ethochloride, benzyl chloride, monohydrochloride, dihydrochloride, monoacetate, benzoate, citrate and sulphate; (2) b - ...
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