摘要:
A process for preparing a cephalosporin ester which comprises subjecting an organic halide or an alcohol to reaction with a cephalosporin acid, a cephalosporin acid halide or a salt thereof in the presence of liquid sulfur dioxide.
摘要:
A novel ester of a cephem compound having a carboxyl group at the 4-position in the nucleus; a process for preparing the same by reacting a cephem carboxylic acid or its salt with a halogenide; and a method for removing the protective group for the carboxyl group in the nucleus of a cephem compound by contacting it with an alcohol, or with an organic solvent in the presence of a Lewis acid.
摘要:
A process for preparing a cephalosporanic acid derivative or a 7-acylaminocephalosporanic acid derivative which comprises subjecting an esterifying agent to reaction in liquid sulfur dioxide in the presence of a base with an N-protected-cephalosporin C to obtain a diester, subjecting the diester to reaction in an inert solvent with an iminohalide forming agent to produce an iminohalide, subjecting the iminohalide with a lower alcohol to produce an iminoether, subjecting the product produced, after subjecting the iminoether to reaction with a reactive derivative of an organic acid, to hydrolysis and further eliminating the ester group of the carboxylic acid.
摘要:
A 9,3"-di-acyl derivative of a macrolide antibiotic can be readily produced by reacting a macrolide antibiotic or an acyl derivative thereof with an organic acid halide, particularly an alkanoic acid halide, in a solvent and in the presence of a molecular sieve consisting of a synthetic zeolite and then de-acylating partially the resultant acylation products by a partial hydrolysis in an aqueous alcohol to give the 9,3"-di-acyl derivative of the macrolide antibiotic.
摘要:
A new cephalosporin compound is now provided, which is useful as antibacterial agent and is represented by the general formula (I) ##STR1## wherein R.sup.1 is an amino group or a protected amino group; R.sup.2 is a hydrogen atom, a salt-forming cation or a carboxyl-protecting group; R.sup.3 is a hydrogen atom, a halogen atom, a lower alkylthio group, a lower alkoxyl group, a vinyl group or a group of the formula: --CH.sub.2 Y where Y is a hydrogen atom, a halogen atom, an acyloxy group, an unsubstituted or substituted heterocyclic thio group or an unsubstituted or substituted pyridinio group, and a pharmaceutically acceptable salt or ester thereof.
摘要:
A class of new caphalosporin compounds (syn-isomer) is now provided, which is useful as antibacterial agent and is represented by the general formula (I) ##STR1## wherein R.sup.1 is an amino group or a protected amino group; R.sup.2 is a lower alkyl group, a carboxymethyl group or a protected carboxymethyl group; R.sup.3 is a hydrogen atom, a salt-forming cation or a carboxyl-protecting group; A is an unsubstituted or substituted phenyl group, an unsubstituted or substituted furyl group, an unsubstituted or substituted thiazolyl group or an unsubstituted or substituted 3-lower-alkylthiazolio group, and a pharmaceutically acceptable salt or ester thereof.
摘要:
This is a class of antibacterial compounds of the formula: ##STR1## wherein Y is straight or branched alkyl or alkenyl chain, cycloalkanomethyl of 3-6 carbon atoms, each group being optionally substituted by halogen, or a group ##STR2## wherein n is 0 or an integer of 1-3, A is a group --COR.sup.3 wherein R.sup.3 is hydroxy, a group ##STR3## wherein R.sup.4 and R.sup.5, which may be the same or different, are hydrogen or alkyl of 1-5 carbon atoms, a group ##STR4## or a 5- or 6-membered heterocyclic group containing nitrogen and/or sulfur, and R.sup.1 and R.sup.2, which may be the same or different, are hydrogen, alkyl of 1-5 carbon atoms, or R.sup.1 and R.sup.2 may be combined together to form cycloalkylidene of 3-5 carbon atoms, and Z is a group of the formula: ##STR5## wherein m is 0 or an integer of 3-5, R.sup.6 is hydrogen or alkyl of 1-3 carbon atoms, and R.sup.7, when m is an integer of 3-5, is alkyl of 1-5 carbon atoms, alkenyl, cyclopropyl, a group --(CH.sub.2).sub.p B wherein p is 0 or an integer of 1-3 and B is amino, alkyl-substituted amino, hydroxy, carboxy, carbamoyl, trifluoromethyl, sulfonic acid, sulfonic acid amide, alkylthio or cyano or, when m is 0, is alkyl of 1-5 carbon atoms, which may optionally be substituted by halogen, alkenyl, a group ##STR6## wherein R.sup.8 is hydrogen, alkyl of 1-4 carbon atoms or phenyl, or cyclopropyl, and a salt thereof.
摘要:
New routes are provided for the synthesis of 3',4'-dideoxykanamycin B which is effective in inhibiting kanamycin-resistant organisms from kanamycin B through new intermediate, of which a fundamental process comprises a new reaction of a 3',4'-epoxy derivative of amino- and hydroxyl-protected kanamycin B with a xanthate to form a corresponding 3',4'-dideoxy-3'-eno derivative followed by removal of the amino- and hydroxyl-protecting groups thereof and by hydrogenation of the resulting 3',4'-dideoxy-3'-eno-kanamycin B. A 3',4'-episulfide derivative corresponding to the 3',4'-epoxy derivative which is formed as second product in the reaction of 3',4'-epoxy derivative with xanthate is also used as intermediate for the preparation of 3',4'-dideoxykanamycin B.
摘要:
New routes are provided for the synthesis of 3',4'-dideoxykanamycin B which is effective in inhibiting kanamycin-resistant organisms from kanamycin B through new intermediate, of which a fundamental process comprises a new reaction of a 3',4'-epoxy derivative of amino- and hydroxyl-protected kanamycin B with a xanthate to form a corresponding 3',4'-dideoxy-3'-eno derivative followed by removal of the amino- and hydroxyl-protecting groups thereof and by hydrogenation of the resulting 3',4'-dideoxy-3'-eno-kanamycin B. A 3',4'-episulfide derivative corresponding to the 3',4'-epoxy derivative which is formed as second product in the reaction of 3',4'-epoxy derivative with xanthate is also used as intermediate for the preparation of 3',4'-dideoxykanamycin B.
摘要:
4-Amino-2-hydroxybutyric acid or 2,4-diaminobutyric acid may be readily produced by a new process comprising reacting a propionic acid compound containing a .beta.-carboxamido substituent (-CONH.sub.2) on the carbon atom at the 3-position and optionally containing hydroxyl substituent and protected or unprotected amino substituent on the .alpha.-carbon atom thereof, with an alkanoic acid anhydride in liquid pyridine to convert the carboxamido group into a nitrile group, with occasional acylation of a .alpha.-hydroxyl group, occasionally removing the alkanoyl group from the .alpha.-acyloxyl group of the resulting nitrile intermediate, and then reducing the resultant nitrile compound with hydrogen to convert the nitrile group into an aminomethyl group, and further optionally removing the residual amino-protecting group from the resultant 4-aminobutyric acid compound.