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Biomedical subjects

B G Christensen

Publications and source records attributed to B G Christensen.

At least 19 recordsLinked to original sources
PubMed1990

Synthesis and antibacterial activity of novel 2-methyl-1-oxacephalosporins.

New 2-methyl-1-oxacephem compounds having 2-(2-aminothiazol-4-yl)-2-(alkoxyimino)acetamido substituents at C-7 and various C-3 side chains were synthesized starting from (3R,4S)-phenyloxazolinoazetidinone (8). Introduction of the 2 beta-methyl group into the 1-oxacephem nucleus increased the stability to beta-lactamases. OCP-9-176 (7b) having the (1-methylpyridinium-4-yl)thiomethyl group at C-3 showed potent antibacterial activity and a broad spectrum.

Bacteria↗
PubMed1987

Structure-activity relationships in the 2-arylcarbapenem series: synthesis of 1-methyl-2-arylcarbapenems.

The labile tert-butyldimethylsilyl esters of the azetidinones 6-8b served as the crucial synthons in the preparation of the potentially useful ylide pyridyl thio esters 18-20. These intermediates were utilized to synthesize a host of title carbapenems 25-30d, 32, and 49-53. The antimicrobial properties and DHP-I susceptibility of these carbapenems were studied with reference to thienamycin.

Anti-Bacterial Agents↗
PubMed1980

A stereocontrolled, enantiomerically specific total synthesis of thienamycin.

A versatile stereocontrolled total synthesis of thienamycin starting from L-aspartic acid is reported. Stereocontrol is achieved by potassium tri-sec-butylborohydride reduction of a thermodynamically formed 3 alpha-acetylazetidinone intermediate. The key [3.2.0] bicyclic ring system is prepared by a metal catalyzed carbene insertion reaction.

Anti-Bacterial Agents↗
PubMed1977

Total syntheses of (+/-)-1-carbacefoxitin and -cefamandole and (+/-)-1-oxacefamandole.

The total syntheses of the (+/-)-1-carba analogues of cefoxitin (11), 7 alpha-methoxydeacetylcephalothin (5) and cefamandole (31) and the (+/-)-1-oxa analogue of cefamandole (43) are described. Their bioactivity spectra against 14 typical organisms are similar to those of their natural 1-thia counterparts, with the 1-carba compounds somewhat less active and the 1-oxa compound more active than the natural ones.

Bacteria↗