Urethans carboxylic acid chloride

There is obtained from 4-[)3-[5-methyl-isoxazolyl-(3)-carboxamido]-ethyl]-benzene-sulfonamide (prepared from 5-methyl-isoxazole-(3)-carboxylic acid chloride and 4-()3-aminoethyl)-benzene-sulfonamide hydrochloride, MP 213° to 214°C in pyridine) and chloroformic acid methyl ester, in a yield of 69%, the compound N-[ [-4-[)3-[5-methyl-isoxazolyl-(3)-carbox-amido] -ethyl] ] -benzene-sulfonyl] ] -methyl-urethane in the form of colorless crystals of MP 173°C. 

Without additional reagents Urethans from carboxylic acids via carboxylic acid chlorides, carboxylic acid azides, and isocyanates Shortened Curtins degradation... 

Urethans from carboxylic acid chlorides GOCl NHGOOR... 

In the absence of n-butanol, the reaction between DBTDL and carbamoyl chloride was very slow (dotted curve). In the presence of n-butanol (solid curve) the completion of the reaction was very fast as can be seen from the disappearance of the carboxylate anion band ( 1600 cm l) and the formations of dimerized acid band (- 1700 cm l) and urethane bands ( 1700 cm-1, v(C=0) 1535 cm- (NH)). This reaction can be depicted as follows ... 

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