摘要:
Multi-step one-pot process for the preparation of inter alia 7β-amino- and 7β-acylamino-3-substituted methyl-3-cephem-4-carboxylic acid derivatives starting from 7p-acylamino-3-methyl-3-cephem-4-carboxylic acid 1β-oxide derivatives, comprising a new process for deoxygenation of generally 7p-acylamino-3-cephem-4-carboxylic acid 1-oxide derivatives optionally substituted in the 7a-position, which can be applied as single step or can be incorporated in multistep processes without isolation of intermediates. The deoxygenation involves the use of phosphorus pentachloride and an olefine for removal of chlorine at least in part by addition to carbon-carbon double bond. Preferred aspects are lasting protection of reactive substituents by silylation and preparation on industrial scale of generally 7β-amino-3-heterocyclic thiomethyl-3-cephem-4-carboxylic acids starting from suitably 7p-phenylacetamido-3-methyl-3-cephem-4-carboxylic acid 9β-oxide.
摘要:
Process for the preparation of [D-a-amino-(p- hydroxyphenyl)acetamido] groups containing cephalosporanic acid derivatives, comprising the acylation of a compound of the formulae: wherein R,, R 2 and R 3 representthe same or a different group and may be selected from a lower alkyl, benzyl, cycloalkyl or. phenyl-group and preferably lower alkyl and more preferably a methyl group an wherein X represents a residue selected from the group consisting of hydrogen, acetoxy or a five-membered heterocyclic thio residue, containing heteroatoms selected from nitrogen, oxygen, and/or sulphur and optionally substituted by lower alkyl and wherein an eventually present -NH- radical has optionally been silylated, which compound is previously prepared by the reaction of 7-aminocephalosporanic acid or its 3-methyl modifications with at least one equivalent and preferably about two with respect to other 3-methyl modifications of 7-ACA of a tri(lower)alkyl silyl groups supplying agent in a dry, inert, water insoluble solvent, such as methylene chloride, by rapid mixing of a pre-cooled solution of the compound offormulae I and Il with a pre-cooled reaction mixture of at least an equimolecular amount of a compound of the formula
wherein R 4 represents lower alkyl and preferably methyl, R 5 represents hydrogen or lower alkyl and preferably methyl, R 6 represents lower alkoxy and preferably methoxy,
and R 7 represents lower alkoxy and preferably methoxy, previously prepared from the corresponding Dane salt and an acid chloride under anhydrous conditions in the presence of a tertiary amine as catalyst, such as N-methylmorpholine in a dry, inert, water insoluble, organic solvent such as methylene chloride mixed with a co-solvent or methyl isobutylketone or tetrahydrofuran optionally mixed with a co-solvent, and the continuation of the reaction at a temperature of -10°C or lower and preferably from -20°C to -30°C whereafter the desired compound is recovered by usual methods.
摘要:
Process for the preparation of / D-a-amino-p- hydrox- yphenylacetamido/ groups containing penicillanic acid and cephalosporanic acid derivatives, comprising the acylation of a compounds of the formulae: and/or or and/or wherein R 1 , R 2 , and R 3 represent the same or a different group and may be selected from a lower alkyl, benzyl, cycloalkyl or phenyl-group and preferably lower alkyl and more preferably a methyl group and wherein X represents a residue selected from the group consisting of hydrogen, acetoxy or a fivemembered heterocyclic thio residue, containing heteroatoms selected from nitrogen, oxygen and/or sulphur and optionally substituted by lower alkyl and wherein an eventually present -NH- radical has optionally been silylated, which compound is previously prepared by the reaction of -6-aminopenicillanic acid or 7-aminocephalosporanic acid or its 3-methyl modifications with at least one equivalent and preferably about 2 with respect to 6-APA, 7-ACA or 7-ADCA and about 3 equivalents with respect to other 3-methyl modifications of 7-ACA of a tri(lower)alkyl silyl groups supplying agent in a dry inert, water insoluble solvent, such as methylene chloride, by rapid mixing of a pre-cooled solution of the compound of formula I-IV with a pre-cooled reaction mixture of at least an equimolar amount of a compound of the formula wherein R 4 represents lower alkyl and preferably methyl, R 5 represents hydrogen or lower alkyl and preferably methyl, R 6 represents lower alkoxy and preferably methoxy and R 7 represents lower alkoxy and preferably methoxy, previously prepared from the corresponding Dane salt and an acid chloride under anhydrous conditions in the presence of a tertiary amine as catalyst, such as N-methylmorpholine in a dry, inert, water insoluble, organo solvent such as methylene chloride mixed with a cosolvent or methyl isobutylketone or tetrahydrofuran optionally mixed with a cosolvent, and the continuation of the reactior at a temperature of -10°C or lower and preferably from 2°C to 30°C whereafter the desired compound is recovered by usual methods.
摘要:
Preparation of 6 alpha-bromo- and/or 6,6-dibromo- penicillanic acid 1,1-dioxides by diazotising a 6 beta-amino- penicillanic acid, 1,1-dioxide and subsequently brominating the diazotised compounds. The bromo-compounds prepared according to the invention are valuable intermediates because they can be debrominated to yield penicillanic acid 1,1-dioxide and derivatives thereof. The preparation of 6-diazo-penicillanic aicd 1,1-dioxide and derivatives thereof is also disclosed as well as these new compounds as such.
摘要:
Preparation of penicillanic acid 1,1-dioxide-and derivatives thereof by debromination of 6-alpha-bromo- and/or 6,6-dibromopenicillanic acid 1,1-dioxides. The debromination is effected in a water-containing medium by reduction with zinc in association with an acid having a pKa-value measured in water less than 3.5.
摘要:
Preparation of penicillanic acid 1,1-dioxide-and derivatives thereof by debromination of 6-alpha-bromo- and/or 6,6-dibromopenicillanic acid 1,1-dioxides. The debromination is effected in a water-containing medium by reduction with zinc in association with an acid having a pKa-value measured in water less than 3.5.