abstract |
The present invention is R 1 is hydrogen or an organic substituent (s), to the R 2 formula (a) fused bicyclic heterocyclic ring system (wherein, R 4 and R 5 is a hydrogen atom in the hydrogen or ring system independently of the M is 2 or 3 and p is 0, 1 or 2, and R 3 is hydrogen, a salt forming cation or an ester forming group, and the symbol = / = represents a double bond in the E or Z coordinate (I) < / RTI > |