| abstract |
The present invention provides a compound of general formula (I) in which Y is a primary or secondary amino group; R2 is the residue of a natural or synthetic amino acid; R3 is hydrogen or a C1-C8 alkyl chain which may be substituted by hydroxy or halogen; and X is (CH2)n where n is 1, 2, or 3, or is CH2N or represents a fused phenyl ring which is optionally substituted by one or two methoxy groups or a salt thereof. |