摘要:
A process is described for preparing 3-exomethylene cephalosporanic acid derivatives for use in the synthesis of cephalosporin antibiotics such as ceftibuten. The process comprises electrochemical reduction of a compound of the formula (IV) ##STR1## wherein: R.sup.3 is CH.sub.3 C(O)--; ##STR2## is an optional sulfoxide group; n is 2 or 3; R.sup.1 is H and R is H or NHR.sup.2, where R.sup.2 is H or a protecting group selected from C.sub.6 H.sub.5 CH.sub.2 OC(O)--, C.sub.6 H.sub.5 C(O)-- or C.sub.1 -C.sub.6 alkoxy-C(O)--; or wherein R and R.sup.1 together with the carbon atom to which they are attached comprise --C(O)--, and produces the desired 3-exomethylene compounds with low levels of the corresponding 3-methyl tautomers.
摘要:
A process is described for preparing 3-exomethylene cephalosporanic acid derivatives for use in the synthesis of cephalosporin antibiotics such as ceftibuten. The process comprises electrochemical reduction of a compound of the formula (IV) ##STR1## wherein: R.sup.3 is ##STR2## is an optional sulfoxide group; n is 2 or 3; R.sup.1 is H and R is H or NHR.sup.2, where R.sup.2 is H or a protecting group selected from C.sub.6 H.sub.5 CH.sub.2 OC(O)--, C.sub.6 H.sub.5 C(O)-- or C.sub.1 -C.sub.6 alkoxy-C(O)--; or wherein R and R.sup.1 together with the carbon atom to which they are attached comprise --C(O)--, and produces the desired 3-exomethylene compounds with low levels of the corresponding 3-methyl tautomers.
摘要:
A process is described for preparing 3-exomethylene cephalosporanic acid derivatives for use in the synthesis of cephalosporin antibiotics such as ceftibuten. The process comprises electrochemical reduction of a compound of the formula (IV) ##STR1## wherein: R.sup.3 is CH.sub.3 C(O)--; ##STR2## is an optional sulfoxide group; n is 2 or 3; R.sup.1 is H and R is H or NHR.sup.2, where R.sup.2 is H or a protecting group selected from C.sub.6 H.sub.5 CH.sub.2 OC(O)--, C.sub.6 H.sub.5 C(O)-- or C.sub.1 -C.sub.6 alkoxy--C(O)--; or wherein R and R.sup.1 together with the carbon atom to which they are attached comprise --C(O)--, and produces the desired 3-exomethylene compounds with low levels of the corresponding 3-methyl tautomers.
摘要:
A compound having the following general formula (I): ##STR1## where R is a hydrogen atom; a linear or branched C.sub.1 -C.sub.4 alkyl group, unsubstituted or substituted by at least a phenyl group or at least a hydrogen atom; a benzyl group substituted by at least a linear or branched C.sub.1 -C.sub.4 alkyl or alkoxy group or a nitro group; a silyl substituted by at least a linear or branched, unsubstituted or substituted C.sub.1 -C.sub.4 alkyl group; n is 0 or 1; and Y is a radical of formula ##STR2## wherein A is H, OH, Cl, CH.sub.2, CH.sub.2 X, where X is F, Cl, Br, I, OH or OR' and R' is COCH.sub.3 or a linear or branched, unsubstituted or substituted C.sub.1 -C.sub.4 alkyl group and - - - represents a single or a double bond, with the proviso that when n=0 and R is H, R' is not a methyl group.
摘要:
Cefazolin, cefazedone, cefoperazone, cefamandole, cefatrizine or ceftriaxone is prepared by reacting glutaryl 7-ACA of the formula: ##STR1## with a compound of formula (II):R--SH (II)wherein R is 5-methyl-1,3,4-thiadiazol-2-yl, 1H-1,2,3-triazol-4-yl, 1-methyl-tetrazol-5-yl or1,2,5,6-tetrahydro-2-methyl-5,6-dioxo-1,2,4-triazin-3-yl group, and R.sup.1 and R.sup.2 are both hydrogen and the other is an acyl group, in an aqueous solution in an amount of 3-5 mols per mol of glutaryl 7-ACA to about 90.degree. C. and for a time from about 2 to about 10 hours;optionally recovering the excess of the compound of formula (II), thereby preparing a compound of formula (III) in an aqueous solution: ##STR2## wherein R is as above defined and optionally deacylating said compound of formula (III); andconverting the resulting compound of formula (I) ##STR3## wherein R, R.sup.1 and R.sup.2 are as defined above in the presence of a non-chlorinated solvent into one of said cephalosporins.
摘要:
There are disclosed new compounds of formula (I), wherein R is: a hydrogen atom: a linear or branched C1-C4 alkyl group, unsubstituted or substituted by at least a phenyl group or at least a hydrogen atom: a benzyl group substituted by at least a linear or branched C1-C4 alkyl or alkoxy group or a nitro group; a silyl substituted by at least a linear or branched, unsubstituted or substituted C1-C4 alkyl group; n is 0 or 1; and Y is a radical of formula (II), wherein A is H, OH, Cl, CH2, CH2X, where X is F, Cl, Br, I, OH or OR' and R' is COCH3 or a linear or branched, unsubstituted or substituted C1-C4 alkyl group and . . . represents a single or a double bond, with the proviso that when n=0 and R is H, R' is not a methyl group; and processes for obtaining them.
摘要:
Process for the alkylation of phenols comprising reacting a phenol with a vinyl-aromatic hydrocarbon in the presence of an acidic catalyst and of a solvent.
摘要:
A process for producing a silane or siloxane compound containing at least one cycloalkyl ring by hydrogenation of a corresponding derivative containing at least one aromatic ring in the presence of a Raney nickel catalyst modified with chromium.
摘要:
A process of producing a silanic or siloxanic compound containing at least one cycloalkyl ring by hydrogenation of a corresponding compound containing at least one aromatic ring, in solution, in the presence of a catalyst comprising palladium, supported on active carbon and at a pressure equal to or higher than 10 bar.
摘要:
A process for the chlorination of the benzene rings of tricyclo 8.2.2.2 hexadeca 4,6,10,12,13,15 hexane (or (2,2)-paracyclophane) having the formula (I): ##STR1## by gaseous chlorine, by operating in the presence of at least one metal chloride as a catalyst, and at least one co-catalyst having the formula V:R--OH (V)whereinR=hydrocarbon or alkylcarboxylic radical with linear or branched chain, containing from 1 to 6 carbon atoms is taught.