Antibiotics, their preparation and use.

摘要

Compound of formula (II) and salts and esters are useful for treating bacterial infections: <CHEM> wherein: R<1> is hydrogen, -CHO, or -SO3H or a pharmaceutically acceptable salt thereof; R<2> and R<3> are independently hydrogen, hydrocarbon, hydrocarbylcarbonyl, hydrocarbylcarbonylamino; or R<2> and R<3> together with the nitrogen atom to which they are attached form a heterocyclic ring; R<2> and R<3> being optionally substituted.