70978-62-0Relevant articles and documents
Selective esterifications of alcohols and phenols through carbodiimide couplings
Shelkov, Rimma,Nahmany, Moshe,Melman, Artem
, p. 397 - 401 (2007/10/03)
Esterification of carboxylic acids capable of forming ketene intermediates upon treatment with carbodiimides permits the selective acylation of alcohols in the presence of phenols lacking strong electron-withdrawing groups. The selectivity of acylations involving highly acidic phenols could be reversed through the addition of catalytic amount of acid. Esterification of other carboxylic acids was found to proceed through the formation of symmetric anhydrides and provide the opposite chemoselectivity. In both cases the relative acylation rates of substituted phenols are consistent with a reaction mechanism involving an attack of phenolate anions on electrophilic intermediates such as ketenes and symmetric anhydrides, with the carbodiimides serving both as an activating reagent and as a basic catalyst.
2'Hydroxy tetrazole-5-carboxanilides and anti-allergic use thereof
-
, (2008/06/13)
New tetrazole derivatives of the general formula: STR1 [wherein R1 represents a halogen atom, a straight- or branched-chain alkyl, alkoxy, alkylthio, alkylsulphinyl, alkylsulphonyl or alkylsulphamoyl group, each such group containing from 1 to 6 carbon atoms, a dialkylsulphamoyl, dialkylamino, or dialkylcarbamoyl group (wherein the two alkyl groups may be the same or different and each contains from 1 to 4 carbon atoms), a straight- or branched-chain alkanoyl, alkoxycarbonyl, alkoxycarbonylamino, alkylcarbamoyl or alkanoylamino group containing from 2 to 6 carbon atoms, a cycloalkylcarbonyl group containing from 3 to 8 carbon atoms in the cycloalkyl moiety, or a hydroxy, formyl, nitro, trifluoromethyl, trifluoroacetyl, aryl, benzyloxycarbonylamino, amino, sulphamoyl, cyano, tetrazol-5-yl, carboxy, carbamoyl, benzyloxy, aralkanoyl or aroyl group, or a group of the formula: (wherein R2 represents a hydrogen atom or a straight- or branched-chain alkyl group containing from 1 to 5 carbon atoms, an aryl, aralkyl or trifluoromethyl group, or a cycloalkyl group containing from 3 to 8 carbon atoms, and R3 represents a hydrogen atom, or a straight- or branched-chain alkyl group containing from 1 to 6 carbon atoms optionally substituted by a phenyl group, or represents an aryl group optionally substituted by one or more substituents selected from halogen atoms and straight- or branched-chain alkyl and alkoxy groups containing from 1 to 6 carbon atoms and hydroxy, trifluoromethyl and nitro groups), and m represents zero or an integer 1, 2 or 3, the substituents R1 being the same or different when m represents 2 or 3] possess pharmacological properties, in particular properties of value in the treatment of allergic conditions.
