Synthesis of N-hydroxysuccinimidyl benzoate and its structural insight into labeling activity of fluorescent probes

N-Hydroxysuccinimidyl benzoate was prepared as a model compound of fluorescent probes. Its crystal structure was determined. The interlayer space between neighbored aromatic rings is inserted by the carbonyl group of succinimidyl moiety and the stacking distance between aromatic rings is as far as 5.9085 Å. Labeling activity of carbonyl groups in N-hydroxysuccinimidyl benzoate was studied by AM1 semiempirical method and the result indicated that carbonyl group consisting of O4 and C5 was responsible for the labeling reaction center.