Abstract: The present invention relates to a process for preparing vinyl carboxylates, wherein a carboxylic acid is reacted with an alkyne compound in the presence of a catalyst which is selected from salts of perrhenic acid at a temperature of =250° C. The process gives rise to the desired vinyl esters with a high yield.

Abstract: The present invention relates to a process for preparing vinyl carboxylates, wherein a carboxylic acid is reacted with an alkyne compound in the presence of a catalyst which is selected from salts of perrhenic acid at a temperature of =250° C. The process gives rise to the desired vinyl esters with a high yield.

Abstract: A process for preparing N-acyl derivatives of the formula I, in which the substituents independently of one another have the following meanings: X is CH(OR3)2, COOR3; R1 is hydrogen, C1-C12-alkyl, aryl, unsubstituted or substituted; R2 is hydrogen, C1-C12-alkyl, aryl, unsubstituted or substituted; R3 is C1-C12-alkyl, which comprises reacting a carboxamide R1—CONH2 of the formula II with a glyoxal monoacetal derivative of the formula III, in the presence of a carboxylic acid R4—COOH of the formula IV where R4=C1-C12-alkyl, where the substituents R1 to R3 are as defined above, is described.

Abstract: Pyrroles of the formula (I) are prepared by dehydrogenating pyrrolidines of the formula (II) where R1 and R2, independently of one another, are hydrogen or an aliphatic radical of 1 to 6 carbon atoms, or pyridines of the formula (III) are prepared by dehydrogenating piperidines of the formula (IV) where R3, R4 and R5, independently of one another, are hydrogen or an aliphatic radical of 1 to 6 carbon atoms, in the presence of a supported noble metal catalyst, by a process in which the dehydrogenation is carried out in the presence of from 1 to 50% by weight, based on the pyrrolidine or piperidine and water, of water.

Abstract: An acylcyclohexadionethiocarboxylic S-ester of the formula ##STR1## where R.sup.1 and R.sup.2 are substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, benzyl or phenyl, and R.sup.2 is additionally hydrogen, are prepared by reacting an acylcyclohexadione II ##STR2## with hydroxylamine or hydroxylamine-O-sulfonic acid in an inert solvent at from 0.degree. to 150.degree. C., to give an acylcyclohexadione compound III ##STR3## and then reacting the compound III with a mercaptan IVR.sup.2 --SH IVin the presence of an anhydrous acid HX to give an acylcyclohexadionethiocarboximidic S-ester salt V ##STR4## where X is the anion of the acid, and hydrolyzing the compounds V to the acylcyclohexadionethiocarboxylic S-ester I.

Abstract: An acylcyclohexadionethiocarboxylic S-ester of the fomrula ##STR1## where R.sup.1 and R.sup.2 are substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, benzyl or phenyl, and R.sup.2 is additionally hydrogen, are prepared by reacting an acylcyclohexadione II ##STR2## with hydroxylamine or hydroxylamine-O-sulfonic acid in an inert solvent at from 0.degree. to 150.degree. C., to give an acylcyclohexadione compound III ##STR3## and then reacting the compound III with a mercaptan IVR.sup.2 --SH IVin the presence of an anhydrous acid HX to give an acylcyclohexadionethiocarboximidic S-ester salt V ##STR4## where X is the anion of the acid, and hydrolyzing the compounds V to the acylcyclohexadionethiocarboxylic S-ester I.