Fig. 2

Reaction mechanism of 2,5-dihydroxybenzoic acid derivatives (1a, Ia, IIa, 3a R1 = NH(CH2)2OH and 1b, Ib, IIb, 3b R1 = COOCH3) and 6-aminopenicillanic acid (2a)
Reaction mechanism of 2,5-dihydroxybenzoic acid derivatives (1a, Ia, IIa, 3a R1 = NH(CH2)2OH and 1b, Ib, IIb, 3b R1 = COOCH3) and 6-aminopenicillanic acid (2a)