Beecham Group Plc

Desmond John Best

Harry Ferres

Adrian Victor Kemmenoe

George Burton

A compound having the partial structure (I) ##STR1## wherein R.sup.1 and R.sup.2 may be the same or different and each is hydrogen or a group --COR.sup.5 or --CO--OR.sup.5 wherein R.sup.5 represents an optionally substituted hydrocarbon group; R.sup.3 is halogen and R.sup.4 is hydrogen, methoxy, hydroxymethyl or formamido. These compounds are suitably bicyclic .beta.-lactam antibiotics.

Antibacterial penicillins and cephalosporins

The preparation and use of 6,.alpha.-methoxy-6,.beta.-[2-(2-methylphenoxycarbonyl)-2-(thien-3-yl) acetamido] penicillanic acid of formula (II): ##STR1## or a pharmaceutically acceptable salt or in vivo hydrolysable ester thereof.

Penicillin derivatives

Aminoacylpenicillins are disclosed which possess a broad spectrum of antibacterial activity.

Penicillins

New penicillins and their salts and esters particularly active against Gram-negative organisms such as Pseudomonas spp., and their preparation and administration. The penicillins are active against clinically important organisms against which well-known broad spectrum penicillins are inactive and may generally be designated as aminoacyldipeptide penicillins of unusual structure and properties.

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Sutton, United Kingdom

Desmond John Best