摘要:
Dodeca-substituted derivatives of macrocyclic tetramers, obtained by acid-catalyzed condensation of pyrogallol and an aliphatic aldehyde, wherein the substituents are alkanoyl groups, are described. These substituted tetramers are optically anisotropic in the molten state and, in particular, show mesophases of the pyramidal type.
摘要:
The invention relates to a process for the preparation of 2-alkyl-cyclopent-2-enones of formula by the following steps. 1) An a-olefin of formula CH 2 =CH--CH 2 R is oxidized to the corresponding epoxide. 2) The epoxide is reacted with an alkylating agent of formula Na + (CH-(COOR") 2 ]- wherein R" is an ethyl, isopropyl or isobutyl radical, to obtain an α-carbalkoxy-γ-alkyl lactone. 3) The lactone is saponified to obtain the corresponding acid. 4) The acid is decarboxylated to obtain a γ-alkyl lactone of formula: 5) The γ-alkyl lactone is reacted with a protic acid to thereby obtain, by cyclization, a 2-alkyl-cyclopent-2-enone of formula (I).
摘要:
Carboxylic acids having the general formula: wherein R is selected from aryl, aralkyl, aralkenyl, aralkynyl, heteroaryl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, alkyl, alkenyl and alkynyl groups, optionally substituted by substituents inert under the reaction conditions, are obtained by oxidation of the corresponding aldehydes with an alkali metal or alkaline-earth metal chlorite in the presence of hydrogen peroxide and in an aqueous-organic solvent. The resulting carboxylic acids are utilizable as intermediates for preparing fine chemicals.
摘要:
The invention relates to a process for the preparation of 2-alkyl-cyclopent-2-enones of formula by the following steps. 1) An a-olefin of formula CH 2 =CH--CH 2 R is oxidized to the corresponding epoxide. 2) The epoxide is reacted with an alkylating agent of formula Na + (CH-(COOR") 2 ]- wherein R" is an ethyl, isopropyl or isobutyl radical, to obtain an α-carbalkoxy-γ-alkyl lactone. 3) The lactone is saponified to obtain the corresponding acid. 4) The acid is decarboxylated to obtain a γ-alkyl lactone of formula: 5) The γ-alkyl lactone is reacted with a protic acid to thereby obtain, by cyclization, a 2-alkyl-cyclopent-2-enone of formula (I).
摘要:
Dodeca-substituted derivatives of macrocyclic tetramers, obtained by acid-catalyzed condensation of pyrogallol and an aliphatic aldehyde, wherein the substituents are alkanoyl groups, are described. These substituted tetramers are optically anisotropic in the molten state and, in particular, show mesophases of the pyramidal type.
摘要:
Carboxylic acids having the general formula: wherein R is selected from aryl, aralkyl, aralkenyl, aralkynyl, heteroaryl, heteroarylalkyl, heteroarylalkenyl, heteroarylalkynyl, alkyl, alkenyl and alkynyl groups, optionally substituted by substituents inert under the reaction conditions, are obtained by oxidation of the corresponding aldehydes with an alkali metal or alkaline-earth metal chlorite in the presence of hydrogen peroxide and in an aqueous-organic solvent. The resulting carboxylic acids are utilizable as intermediates for preparing fine chemicals.