Several imidazolium ionic liquid（IL）-supported sulfonic acids with different anions,[C_3SO_3Hmim]HSO_4,[C_3SO_3Hmim]BF_4, [C_3SO_3 Hmim]PF_6,and[C_3SO_3Hmim]CF_3SO_3,were synthesized and applied as catalysts for esterification reaction of benzoic acid. The experimental results indicate that imidazolium IL-supported sulfonic acid containing anion of HSO_4^- shows the best catalytic activity.Only when less[C_3SO_3Hmim]HSO_4（0.3 equiv.） applied,was the product obtained with high yield of 97%.Furthermore, the produced esters could be separated by decantation,and the catalyst could be reused after the removal of water.
Yue Qin CaiGuo Qiang YuChuan Duo LiuYuan Yuan XuWei Wang
A series of compounds 1-11 with different side chains of naphthalimide as fluorescent copper sensors were designed and synthesized. Compounds 1, 9, 10 and 11 presented a high selectivity to Cu2+ in a neutral aqueous environment. Here 1, 9 and 10 showed selectivity and affinity to Cu2+ with an association constant of about ～106. It gave somewhat response to Ag+, Co2+, Ni2+ and Fe2+ while 1 detected copper. 9 and 10 displayed better selectivity by changing their hydrophobic side chains to the hydrophilic ones on imide moieties. 11, with one flexible side chain, showed high selectivity and an association constant (Ka = 2.2 × 108), which were much higher than those of 1, 9 and 10. These results indicated that the selectivity and affinity could be improved by changing side chains of naphthalimide. That might provide a novel strategy or method for the development of fluorescent sensors.
Compared with traditional structure-based approaches for the identification of species-specific ligands, the ab initio approach, based on large-scale protein sequences from different species, has been used to locate specific sites that may be important to the molecular selectivity of species. Statistically significant differences in the distribution of residues in different species and differences in the physicochemical properties of residue-specific sites may largely account for species selectivity. The nicotinic acetylcholine receptor (nAChR), an important neuro-receptor with significantly different ligand selectivity in different species, was used to test our method. Because of the lack of nAChR structural information, the mechanism of ligand discrimination is unclear which hinders attempts at novel molecular design. In this study, the specific site residues 186 and 189 in the principal subunits and residues 34, 55, 56, 57, 106 and 112 in complementary subunits of nAChR were identified by applying our method with stringent statistical cutoffs. These sites were predicted to contribute to ligand selectivity and this result coincides well with the known experimental data.
Started from salicylic acid（SA） and related commercialized plant activators,based on molecular threedimensional shape and pharmacophore similarity comparison（SHAFTS）,a new lead compound benzotriazole was predicted and a series of benzotriazole derivatives were designed and synthesized.The bioassay showed that benzotriazole had high activity against a broad spectrum of diseases including fungi and oomycetes in vivo,but no activity in vitro.And the introduction of proper groups at the1＇-position and 5＇-position was beneficial to the activity.So,they had the potential to be exploited as novel plant activators.
