摘要:
The process according to the invention relates to the preparation of 2-chloromethyl-thiophene of the formula (I). During this process thiophene is chloromethylated in the presence of one or more compounds containing keto group and optionally it is transformed into the compound of the formula (II). Compounds of formula (I) and (II) are intermediates of several pharmaceutically active ingredients.
摘要:
The subject of our invention is the process for the preparation of the 1-(3,4-dimethoxyphenyl)ethanol of formula (I), by the reduction of 3,4-dimethoxyacetophenone of formula (II), characterized in that the carbonyl group of the 3,4-dimethoxyacetophenone of formula (II) is reduced by 1 mol of hydrogen under the conditions of catalytic hydrogenation.
摘要:
The present invention relates to a process for the preparation of compounds of general formula (I), wherein R stands for a straight chained C.sub.1-5 alkyl group substituted by a chlorine atom in the 2-position, and acid addition salts thereof, characterized by reacting a 3,5-dichloro-2-alkanone of general formula (V), wherein R is a defined above, with an inorganic thiocyamate, and a) converting the 3-thiocyanato-5-chloro-2-alkanone of general formula (IV), thus obtained, wherein R is as defined above, into 2-chloro-4-methyl-5-(2-chloroalkyl)-thiazole of general formula (II), wherein R is as defined above, by gaseous hydrochloric acid in an organic solvent, hydrogenating the said compound in the presence of a metal catalyst in an organic solvent, or b) reacting said compound of general formula (IV) with an aqueous mineral acid and treating the 2-hydroxy-4-methyl-5-(2-chloroalkyl)-thiazole of general formula (III), thus obtained with a halogenating agent, and hydrogenating the 2-chloro-4-methyl-5-(2-chloroalkyl)-thiazole of general formula (II) thus obtained, wherein R is as defined above, in an organic solvent in presence of a metal catalyst, and optionally converting the 4-methyl-5-(2-chloroalkyl)-thiazole of general formula (I), wherein R is as defined above, thus obtained or a hydrochloride salt thereof, in a manner known per into another acid addition salt or setting free a compound of general formula (I), wherein R is a defined above, from its acid addition salt.
摘要:
A process is described for the preparation of 4-Methyl-5-(2-Chloroalkyl)-thiazole wherein the alkyl ranges from C.sub.2 -C.sub.5, by providing the steps of either a) converting the 3-thiocyanato-5-chloro-2-alkanone into 2-chloro-4-methyl-5-(2-chloroalkyl)-thiazole by gaseous hydrochloric acid in an organic solvent and hydrogenating the compound in the presence of a metal catalyst in an organic solvent, or b) reacting 3-thiocyanato-5-choro-2-alkanone with aqueous mineral acid and treating the thiazole obtained with a halogenating agent, and hydrogenating the 2-chloro-4-methyl-5-(2-chloroalkyl)-thiazole in an organic solvent in presence of a metal catalyst.
摘要:
The invention relates to a process for the preparation of tetracycline derivatives of the formula ##STR1## and acid addition salts thereof --wherein R stands for --CH.sub.3 or .dbd.CH.sub.2 --by dehalogenating and hydrogenating chloromethacycline or acid addition salt thereof of the formula ##STR2## or by hydrating methacycline or acid addition salts thereof of the formula ##STR3## by treatment with hydrogen gas in the presence of a noble metal alloy catalyst on carrier and organic solvent which comprises performing, hydrogenating under pressure of 0.1-1.0 MPa with an alloy catalyst consisting of the alloy palladium or platinum and selenium and/or tellurium used at a ratio of 1:0.01-0.5 related to the amount of the starting tetracycline and carrying out, if desired dehalogenation and hydrogenation in one step.