Abstract: Process for the preparation of compounds of formula (I) wherein R means hydrogen atom, or C1-6 alkyl group, or C7-12 aralkyl group or phenyl group, characterised in that: a) the compound of formula (III) is reacted with a compound of formula (IV) wherein X means halogen atom or C1-5 alkoxy group or hydroxyl group and the resulting compound of formula (II) is transformed in the presence of an oxidising agent in a reaction medium with pH above 7, into the compound of formula (I), or b) the compound of formula (III) is reacted with an anhydride of general formula (V) and the resulting compound of formula (II) transformed in the presence of an oxidising agent, in a reaction medium with pH above 7, into the compound of formula (I), or c) a compound of formula (II) is transformed in the presence of an oxidising agent, in a reaction medium with pH above 7, into the compound of formula (I), and if desired, the resulting compounds of formula (I), before or after isolation, are transformed into acid addition salts, or

Abstract: Process for the preparation of compounds of formula (I) wherein R means hydrogen atom, or C1-6 alkyl group, or C7-12 aralkyl group or phenyl group, characterised in that a) the compound of formula (III) is reacted with a compound of formula (IV) wherein X means halogen atom or C1-5 alkoxy group or hydroxyl group, and the resulting compound of formula (II) is transformed, in a reaction medium with pH above 7, into the compound of formula (I) or b) the compound of formula (III) is reacted with an anhydride of general formula (V) and the resulting compound of formula (II) transformed, in a reaction medium with pH above 7, into the compound of formula (I), or c) a compound of formula (II) is transformed, in a reaction medium with pH above 7, into the compound of formula (I), and if desired, the resulting compounds of formula (I), before or after isolation, are transformed into acid addition salts, or the compounds of formula (I) are liberated from their acid addition salts.

Abstract: The present invention relates to a process for the preparation of L-isomer of propargyl-ammonium-chloride derivatives of the formula (I) ##STR1## by decomposing D-tartarte of L-isomer of the amine of the general ##STR2## wherein y is hydrogen or fluoro and by reacting the obtained L-issomer amine of the formula (II) in the presence of a base with a halide of the formula (V), X--CH.sub.2 --C.ident.CCH wherein X is halogen and by reacting the so obtained L-isomer of the Formula (III) ##STR3## with hydrogen-chloride in an organic solvent, wherein x is a halogen atom,y is a hydrogen or fluorine atom.

Abstract: 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.

Abstract: The invention relates to a process for the preparation of a new crystalline monohydrate of 1-(3', 4'-diethoxy-benzyl-6, 7-diethoxy-3,4-dihydro-isoquinolinium-theophylline-7-acetate and if desired of pure 1-(3', 4'-diethoxy-benzyl)-6,7-diethoxy-3, 4-dihydro-isoquinolinium-theophylline-7-acetate free of contaminating oxidation products which comprises reacting 1-(3',4'-diethoxy-benzyl)-6,7-diethoxy-3,4-dihydro-isoquinolinium with theophylline-7-acetate acid in the presence of water and one or more organic solvent(s) and if desired dehydrating the 1-(3',4'-diethoxy-benzyl) 6,7-diethoxy-3,4-dihydro-isoquinolinium-theophyl line-7-acetate-monohydrate thus obtained.