Abstract: A process for preparing acetoacetarylamides of the formula I ##STR1## where R.sup.1 and R.sup.2 are identical or different alkyl radicals,l and m are each 0, 1 or 2, andis 0 or 1,by addition of diketene to the appropriate arylamine by continuously reacting the arylamine with diketene in the presence of a mixture of water and of a (C.sub.1 -C.sub.4)-alkanol at temperatures from 60.degree. C. to 100.degree. C. in the course of from 0.1 to 10 min.

Abstract: A process for preparing 5-acetoacetylamino-2-benzimidazolone by continuous reaction of 5-amino-2-benzimidazolone with diketene comprises carrying out the reaction in the presence of a water-soluble (C.sub.1 -C.sub.4)-alcohol or of a mixture of this alcohol with water at the boiling temperature.

Abstract: 6-Methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide is prepared by cylcizing acetoacetamide-N-sulfonic acid or its salts with an at least approximately equimolar amount of SO.sub.3 in the presence of a water-immiscible, inert organic solvent and, if appropriate, also an inert, inorganic solvent. In the event that an equimolar amount of SO.sub.3 is employed, working up is effected by adding aqueous sulfuric acid when the cyclization reaction is complete; in the event that the amount of SO.sub.3 employed is more than equimolar, the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide obtained in the form of the SO.sub.3 -adduct is hydrolyzed by adding water or ice, whereby sulfuric acid is formed from the SO.sub.3 combined in the SO.sub.3 -adduct.The inert, organic solvent is then removed from the resulting multi-phase mixture by distillation, and the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide is obtained in a pure form from the remaining aqueous sulfuric acid phase by crystallization.

Abstract: The non-toxic salts of 6-methyl-3,4-dihydro-1,2,3-oxothiazin-4-one 2,2-dioxide are prepared by cyclizing acetoacetamide-N-sulfonic acid or its salts with an at least approximately equimolar amount of SO3 in the presence of a water-immiscible, inert organic solvent and, if appropriate, also an inert inorganic solvent, hydrolyzing the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide obtained in the form of the SO3-adduct after the cyclization reaction, in the event that the amount of SO3 employed is more than equimolar, purifying the organic phase (which has separated out) by extraction with a small volume of water or dilute aqueous sulfuric acid, preferably only with water, and isolating, by neutralization with bases, the non-toxic salts of the 6-methyl-3,4-dihydro-1,2,3-oxathiazin-4-one 2,2-dioxide from the organic phase thus purified.The said salts are obtained in this process in an extremely pure form; they are valuable synthetic sweetening agents. The potassium salt is known as acesulfam (K).

Abstract: The invention relates to a process for the preparation of 2-hydroxy-(9H)-carbazole. In this process, 1,2,3,4-tetrahydro-7-hydroxy-(9H)-carbazole is dehydrogenated in an inert organic solvent.

Abstract: Cyclohexane-1,3-diones are prepared by passing .delta.-ketocarboxylic acid esters in the gaseous phase over a temperature of from 250.degree. C. to 500.degree. C. at a catalyst. The catalyst contains at least one element of groups III B or IV B of the Periodic System in the form of a compound. Particularly preferred catalysts are thorium compounds on charcoal carriers.

Abstract: Resorcinols are prepared by converting .delta.-ketocarboxylic acid esters in the gaseous phase at a temperature from 250.degree. to 500.degree. C. in the presence of hydrogen at a catalyst. The catalyst consists of two components which are prepared separately and combined thereafter. The first component contains at least one compound of a metal of group VIII and/or at least one compound of a metal of group I B supported on one or several carrier materials. The second component contains at least one compound of a metal of group II A and/or IV A and/or III B and/or IV B supported on one or several carrier materials. A particularly preferred catalyst consists of a mixture of equal volume parts of platinum/charcoal as first component and of thorium/charcoal as second component.