中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | benzyl cis-7-azido-3-methyl-2-iso-oxacephem-4-carboxylate | 75767-10-1 | C15H14N4O4 | 314.301 |
—— | benzyl 3-methyl-2-iso-oxacephem-4-carboxylate | 163234-32-0 | C15H15NO4 | 273.288 |
—— | (Z)-2-((2S,3S)-3-Azido-2-methanesulfonyloxymethyl-4-oxo-azetidin-1-yl)-3-hydroxy-but-2-enoic acid benzyl ester | 67315-35-9 | C16H18N4O7S | 410.408 |
—— | (2R,3S)-2-((2S,3S)-3-Azido-2-hydroxymethyl-4-oxo-azetidin-1-yl)-3-(tert-butyl-dimethyl-silanyloxy)-butyric acid benzyl ester | 75748-43-5 | C21H32N4O5Si | 448.594 |
—— | (2R,3S)-2-((2S,3S)-3-Azido-2-methanesulfonyloxymethyl-4-oxo-azetidin-1-yl)-3-(tert-butyl-dimethyl-silanyloxy)-butyric acid benzyl ester | 75748-42-4 | C22H34N4O7SSi | 526.686 |
—— | (2R,3S)-2-((2S,3S)-3-Azido-2-methanesulfonyloxymethyl-4-oxo-azetidin-1-yl)-3-hydroxy-butyric acid benzyl ester | 75748-41-3 | C16H20N4O7S | 412.423 |
中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
—— | (6S,7S)-3-Methyl-8-oxo-7-phenylacetylamino-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzyl ester | 75767-12-3 | C23H22N2O5 | 406.438 |
—— | 4-Oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,3-methyl-8-oxo-7-[(phenoxyacetyl)amino]-, phenylmethyl ester, trans- | 62282-25-1 | C23H22N2O6 | 422.437 |
—— | 3-methyl-7t-(4-nitro-benzylideneamino)-8-oxo-(6rH)-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzyl ester | 69809-87-6 | C22H19N3O6 | 421.409 |
—— | (+)-3-methyl-7-phenyl-acetamido-O-2-isocephem | 75767-13-4 | C16H16N2O5 | 316.313 |
—— | 7t-amino-3-methyl-7c-methylsulfanyl-8-oxo-(6rH)-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzyl ester | 69809-93-4 | C16H18N2O4S | 334.396 |
—— | 4-Oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid,3-methyl-8-oxo-7-[(phenoxyacetyl)amino]-, trans- | 62282-26-2 | C16H16N2O6 | 332.313 |
—— | 7c-methoxy-3-methyl-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzyl ester | 69809-97-8 | C24H24N2O7 | 452.464 |
—— | 3-methyl-7c-methylsulfanyl-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzyl ester | 69809-95-6 | C24H24N2O6S | 468.53 |
—— | 3-methyl-7c-methylsulfanyl-7t-(4-nitro-benzylideneamino)-8-oxo-(6rH)-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid benzyl ester | 69809-90-1 | C23H21N3O6S | 467.502 |
—— | 7c-methoxy-3-methyl-8-oxo-7t-(2-phenoxy-acetylamino)-(6rH)-4-oxa-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid | 69809-99-0 | C17H18N2O7 | 362.339 |
The syntheses of 7-methoxy-7-phenoxyacetamido-3-methyl-Δ3-isocephem-4-carboxylic acid 11a, 7-methoxy-7-phenoxyacetamido-3-rnethyl- Δ3-O-2-isocephem-4-carboxylic acid 11b and 7-methoxy-7-(2-thienyl)acetamido-3-acetoxymethyl- Δ3-O-2-isocephem-4-carboxylic acid 11c are described. A sequence analogous to that used to prepare 7-methoxy cephalosporins was used: Schiff base anions were thiomethylated and the Schiff bases hydrolyzed to free amines. The amines were acylated and thiomethyl to methoxyl conversion effected with mercuric ion catalysis. Removal of protective esters gave the acids 11a, 11b, and 11c. Compound 11c showed a modest level but broad spectrum of antibacterial activity.
Starting from D-threonine, an asymmetric synthesis of the dextrorotatory bioactive enantiomer of 3-methyl-7-phenylacetamido-O-2-isocephem was accomplished. The key step, where asymmetric cycloaddition of azidoacetyl chloride to the cinnamylidene Schiff base of protected D-threonine is induced, generates the desired cis-β-lactam in 90% optical yield. The absolute configuration of the final product was confirmed by comparing its antimicrobial activity with that of its corresponding racemate.