Improvements in and relating to light transfer systems and improved cell investigation techniques arising therefrom

摘要

Compound of formula (I) or a salt thereof, wherein R1 is hydrogen, methoxy or formamido; R2 is an acyl group of formula (a), where A¿3? is thiazolyl optionally substituted by an amino group, A4 is hydrogen or an organic residue; CO2R?3¿ is a carboxy group, carboxylate anion, or R3 is a readily removable carboxy protecting group; X is S, SO, SO¿2?, O or CH2; and R?4¿ is an unsaturated acyl group novel and useful in the treatment of bacterial infections in humans and animals.