摘要:
In the production of perparine or papaverine and their hydrochlorides, the formation of impurities in the reaction mixture is suppressed by fractionating a 3,4-di-R-benzyl-cyanide in the presence of an organic base (e.g. pyridine, dimethylformamide, ethylenediamine or triethylamine) followed by hydrogenation with a Raney-nickel catalyst treated with aqueous ammonium carbonate solution. R is methoxy or ethoxy.
摘要:
A process is disclosed for preparing a carbamic acid phenyl ester of the formula (I) ##STR1## wherein R is alkyl having 1 to 8 carbon atoms, aryl, cycloalkyl having 5 or 6 carbon atoms, or aralkyl having 7 to 16 carbon atoms, wherein the aryl, cycloalkyl or aralkyl is unsubstituted or substituted by at least one alkyl group having 1 to 8 carbon atoms;R.sub.1 is hydrogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, cyanomethyl, 1,3-dioxolan-2-yl, or carboalkoxyamino wherein the alkoxy group contains 1 to 4 carbon atoms;R.sub.2 is hydrogen, halogen, alkyl having 1 to 4 carbon atoms or alkoxy having 1 to 4 carbon atoms; orR.sub.1 and R.sub.2 form together a carbocyclic ring or a heterocyclic ring fused to the phenyl ring wherein the carbocyclic ring of the heterocyclic ring is unsubstituted or substituted by at least one alkyl having 1 to 8 carbon atoms, which comprises acylating a phenol of the formula (II) ##STR2## with a compound of the formula (IV) ##STR3## in the presence of a base. The compounds obtained are valuable intermediates.
摘要:
The invention relates to a process for the preparation of carbamic acid phenyl esters of the formula (I) ##STR1## by acylating phenol derivatives of the formula (II) ##STR2## wherein R is alkyl having 1 to 8 carbon atoms, aryl, cycloalkyl having 5 or 6 carbon atoms, aralkyl having 7 to 16 carbon atoms which groups can be substituted by one or more alkyl groups,R.sup.1 is hydrogen, alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms or acylamino,R.sup.2 is hydrogen, halogen, alkyl having 1 to 4 carbon atoms or alkoxy having 1 to 4 carbon atoms, or ifR.sup.1 and R.sup.2 represent alkyl and/or alkoxy, they can form together a carbocyclic ring.According to the invention the phenol derivatives of the general formula (II), wherein R.sup.1 and R.sup.2 are as defined above, are reacted with N-carbamoyl-saccharin derivatives of the formula (IV) ##STR3## wherein R has the same meaning as defined above, in the presence of a base.
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.