摘要:
4,5-Disubstituted imidazole-2-carboxylic acids are prepared by reacting 4,5-disubstituted imidazoles with carbon dioxide under superatmospheric pressure at from 150.degree. to 300.degree. C. in the presence of a base.
摘要:
4(5)-nitroimidazole-5(4)-carboxylic acids are prepared by reacting an imidazole-4(5)-carboxylic acid with a mixture of sulfuric acid and nitric acid at not less than 80.degree. C., the water content of the reaction mixture at the beginning of the reaction being no higher than 5% by weight, based on the reaction mixture.
摘要:
2-Imidazolines are prepared by reacting N,N'-diformyl-1,2-diamines in the gas phase at 200.degree.-350.degree. C., in the presence of certain amounts of an inert gas, over zinc oxide of a particular structure or over a mixture of this zinc oxide and aluminum oxide, as the catalyst.The 2-imidazolines obtainable by the process according to the invention are valuable starting materials for the preparation of dyes, crop protection agents and drugs.
摘要:
2-Alkyl-4,5-dihydroxymethyl-imidazoles of the formula ##STR1## where R is alkyl, are prepared by a process in which an imidazole of the formula ##STR2## is reacted with not less than 2 moles of formaldehyde in the presence of a base.
摘要:
Hexaarylbisimidazoles I ##STR1## where Ar.sup.1, Ar.sup.2 and Ar.sup.3 are each aryl, of which Ar.sup.2 and Ar.sup.3 can be linked to form an anellated ring system, are prepared by oxidizing the corresponding triarylimidazoles II in an aqueous/organic two-phase system in the presence of active amounts of an onium salt III.
摘要:
Imidazole-4(5)-monocarboxylic acids and their salts or betaines are prepared by reacting an imidazole with carbon dioxide and an alkali metal carbonate, an alkali metal bicarbonate and/or an alkali metal hydroxide at from 140.degree. to 230.degree. C. and under from 2 to 350 bar and, if desired, then reacting the product with an acid.The imidazole-4(5)-monocarboxylic acids which can be prepared by the process of the invention are useful starting materials for the preparation of dyes, crop protection agents and drugs.
摘要:
Imidazole-4,5-dicarboxylic acid is prepared by a process in which imidazole is reacted with formaldehyde, and the reaction mixture is treated with nitric acid.
摘要:
A novel process for the preparation of 2-imidazolines by reacting 1,2-diamines with nitriles or carbonyl compounds in the gas phase at from 200.degree. to 450.degree. C. in the presence of an oxide or phosphate of a metal of group 3 or 4 of the periodic table and/or in the presence of silicon dioxide.The 2-imidazolines obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents and drugs.
摘要:
1-Hydroxymethylimidazoles which are unsubstituted or alkyl-substituted in the 2-position, their manufacture and their use as chemical intermediates, e.g. for other imidazole derivatives or for the drug cimetidine.
摘要:
Imidazoles are prepared by reacting 2-imidazolines at from 250.degree. to 500.degree. C. in the presence of molybdenum oxide and nickel oxide and/or cobalt oxide and aluminum oxide, silicon dioxide and/or silicates as catalysts.The imidazoles obtainable by the process according to the invention are valuable starting materials for the preparation of dyes, crop protection agents, textile auxiliaries, catalysts for polyurethanes and epoxy resins, surfactants and drugs, for example the corresponding nitroimidazoles.