28974-31-4Relevant academic research and scientific papers
A New Dihydrothiazine Ring Closure for the Preparation of 3-Methylcephalosporins from Azetidinone Disulfides at 5-10 deg
Davis, Michael,Wu, Wen-Yang
, p. 1519 - 1526 (2007/10/02)
p-Nitrobenzyl (2 R, 3 R)-2-(benzothiazol-2'-yldithio)-α-isopropenyl-4-oxo-3-phenoxyacetylamino-azetidine-1-acetate (3a), readily prepared from penicillin V, is smoothly cyclized by ammonium acetate in a dimethyl sulfoxide/tetrahydrofuran mixture at 5-10 deg to the ceph-3-em ester (2a) in high yield.Other ethers (3b-d), but not the free acid (3e), behave in a similar way.The ceph-3-em esters can be readily de-esterified to the free acid (2e).
Process for converting penicillin sulfoxides to the corresponding 3-desacetoxycephalosporins
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, (2008/06/13)
Conversion of penicillin sulfoxides to the corresponding 3-desacetoxycelphalosporins are carried out in high yield by heating, e.g. 80°-130° C, a solvent solution of the penicillin in the presence of a complex formed by a phosphite or phosphine amide with the salt of a strong acid and a nitrogenous base, e.g. alpha-picoline hydrobromide. One preferred amide is 2-piperidino-1,3,2-dioxaphospolane.
Process for preparing cephalosporins
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, (2008/06/13)
A process for preparing cephalosporins of structure: STR1 where R is hydrogen, C1 to C4 alkyl, cyano-methyl-, thienyl-methyl, furyl-methyl-, naphthyl-methyl-, phenyl-methyl-, phenoxy-methyl-, phenyl-isopropyl-, phenoxy-isopropyl-, pyridyl-4-thiomethyl-, and tetrazolyl-1-methyl; R1 is hydroxyl, C2 to C4 alkoxy, trichloroethoxy-, benzyloxy-, p-methoxy-benzyloxy-, p-nitrobenzyloxy-, benzhydryloxy-triphenylmethoxy-, phenacyloxy-, and p-halophenacyloxy; Z is hydrogen, hydroxyl, --O--alkyl, --O--CO--alkyl, --Br, --I, --N3, --NH2, --O--CO--CH3, --O--CO--NH2 and an --S--mononuclear nitrogen heterocyclic ring; Wherein a compound of structure STR2 is reacted in a suitable solvent at a temperature between -20° C and +80° C, in the presence of an aqueous organic or inorganic acid with an azoderivative of the formula: STR3 where R2 and R3 are equal or different and represent lower alkyl, a mononuclear aryl ring, CN--, a mononuclear heterocyclic ring, or the radicals --COR4, --COOR4, STR4 --CONHR4, or R2 and R3 together may represent the residues: STR5 where T represents >CH2, >N -- R4, and R4 is lower alkyl, a mononuclear aryl ring or a mononuclear heterocyclic ring, to give a compound of structure: STR6 in which R, R1, R2, R3, and Z have the meanings given above, and said intermediate (II 40 ) is reacted in a suitable solvent at a temperature between -100° C and +120° C with a compound selected from the class consisting of inorganic bases, to finally give the desired compound (III) which is isolated and purified in known manner.
3-Halo-cephalosporins
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, (2008/06/13)
A novel ester of 7-acylamido-3-methyl-cepham-4-carboxylic acid derivative and a process for the preparation thereof which comprises reacting penicillin sulfoxide ester with the metal halide, and a novel 7-acylamido-3-methyl-cepham-4-carboxylic acid deriva
Preparation of 6-acylamino-2-methyl-2-halomethyl penams
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, (2008/06/13)
A 7-acylamino-3-hydroxy-3-methylcepham-4-carboxylic acid ester is reacted with a mixture of a halogenating agent and a tertiary carboxamide to produce a 2-halomethylpenam compound, a useful intermediate for the preparation of desacetoxycephalosporins.
Deacetoxycephalosporins via penicillin sulfoxide rearrangement
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, (2008/06/13)
Penicillin sulfoxides, notably the sulfoxides of penicillin V and penicillin G, are heated with amine salts of dichloromethane phosphonate in 1,1,2-trichloroethane to provide superior yields of deacetoxycephalosporins. The process is especially valuable in providing greater yields of the intermediate in the synthesis of the commercial antibiotic, cephalexin.
Process for the preparation of esters of N-blocked penicillin acids which comprises reacting the acid or a salt thereof with a primary amine and a nitrosating agent
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, (2008/06/13)
A process is described for the preparation of esters of N-blocked amino acids (such as penicillins or cephalosporins) wherein the amino acid or a salt thereof is reacted with a primary amine and nitrosating agent.
