The ab initio method has been used to study the 1-3 H transfer reaction on formamidine substituted by halogen. The calculation results show that the substituted halogen has two effects on the 1-3 H transfer reaction...The ab initio method has been used to study the 1-3 H transfer reaction on formamidine substituted by halogen. The calculation results show that the substituted halogen has two effects on the 1-3 H transfer reaction: decreasing the activation energy and stabilizing the C=N double bond owing to the conjugative effect of p-π-p of products and transition states.展开更多
Intra-abdominal injection of amitraz(0.25 nmol per honeybee,i.e.,approx 2.3 nmol/g)to emerging worker bees,in vivo,led to a significant hypertrehalosemia(300-400%)followed by a hyperglucosemia(≈600%).Maxima were reac...Intra-abdominal injection of amitraz(0.25 nmol per honeybee,i.e.,approx 2.3 nmol/g)to emerging worker bees,in vivo,led to a significant hypertrehalosemia(300-400%)followed by a hyperglucosemia(≈600%).Maxima were reached at 0.5 and 2h,respectively.A strong negative correlation between glucosemia and trehalosemia appeared after injection of pure phentolamine (1 nmol per bee),suggesting stimulation of trehalase activities.Simultaneous administration of the α-blocker at≥0.25 nmol per individual suppressed the hyperglycemic response of amitraz. The formamidine pesticide thus likely acts on the honeybee α-aminergic system.1989 Academic Press,Inc.展开更多
The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decrease...The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decreases were observed at 30-45 min with 0.25 nmols per bee, for phospholipids, fatty acids, steroids and triacylglycerols. However increases were observed either later or with higher doses. The decreasing action observed with 0.25 nmol AMZ per bee was inhibited by simultaneous injections of the a antagonist phentolamine (from 0.25 to 2.0 nmols per bee). The toxicity of AMZ to honeybees thus likely involves the mobilization of lipids from the gut, via action of this formamidine pesticide on a-adrenoceptors.展开更多
Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)...Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.展开更多
The redox behaviours of a donor-acceptor model compound. p-tricyano-ethenyl-N, N-dimethyl aniline was investigated by electrochemical and spectroelectrochemical methods. The results indicate that charge transfer betwe...The redox behaviours of a donor-acceptor model compound. p-tricyano-ethenyl-N, N-dimethyl aniline was investigated by electrochemical and spectroelectrochemical methods. The results indicate that charge transfer between the donor(amino) and the acceptor(cyanoethenyl) groups takes place in the process of oxidation of this compound.展开更多
The hydrolysis mechanisms of N,N-dimethyl-N′-(2′,3′-dideoxy-3′-thiacytidine)formamidine (FA-3TC) in the gas phase and in aqueous solution were studied by use of the density functional theory B3LYP/6-31+G(d, p) met...The hydrolysis mechanisms of N,N-dimethyl-N′-(2′,3′-dideoxy-3′-thiacytidine)formamidine (FA-3TC) in the gas phase and in aqueous solution were studied by use of the density functional theory B3LYP/6-31+G(d, p) method. Two possible reaction pathways in the title reaction were considered. In one pathway water attacks the C=N double bond first (path A) while in the other water attacks the C—N single bond first (path B). The calculated results indicate that the first step in both pathways is the rate-limiting process and path A is more favorable than path B in the gas phase. The effect of solvent water on the title reaction was assessed at the B3LYP/6-31+G(d, p) level of theory based on the po-larizable continuum model (CPCM). In water the first mechanism (path A) is also favored.展开更多
基金Supported by the Yunnan Provincial Science and Technology Department (2003A0003M)
文摘The ab initio method has been used to study the 1-3 H transfer reaction on formamidine substituted by halogen. The calculation results show that the substituted halogen has two effects on the 1-3 H transfer reaction: decreasing the activation energy and stabilizing the C=N double bond owing to the conjugative effect of p-π-p of products and transition states.
文摘Intra-abdominal injection of amitraz(0.25 nmol per honeybee,i.e.,approx 2.3 nmol/g)to emerging worker bees,in vivo,led to a significant hypertrehalosemia(300-400%)followed by a hyperglucosemia(≈600%).Maxima were reached at 0.5 and 2h,respectively.A strong negative correlation between glucosemia and trehalosemia appeared after injection of pure phentolamine (1 nmol per bee),suggesting stimulation of trehalase activities.Simultaneous administration of the α-blocker at≥0.25 nmol per individual suppressed the hyperglycemic response of amitraz. The formamidine pesticide thus likely acts on the honeybee α-aminergic system.1989 Academic Press,Inc.
文摘The time-course and dose-related action of amitraz (AMZ) on gut lipids of worker honeybees were examined over 3 hours following in vivo injections of 0.25, 0.5, 1 and 2 nmols of pesticide per bee. Significant decreases were observed at 30-45 min with 0.25 nmols per bee, for phospholipids, fatty acids, steroids and triacylglycerols. However increases were observed either later or with higher doses. The decreasing action observed with 0.25 nmol AMZ per bee was inhibited by simultaneous injections of the a antagonist phentolamine (from 0.25 to 2.0 nmols per bee). The toxicity of AMZ to honeybees thus likely involves the mobilization of lipids from the gut, via action of this formamidine pesticide on a-adrenoceptors.
文摘Five new zwitterionic surfactants with long chain alkyl betaine structure incorporated with hydroxylpropyl group have been synthesized. Their structures were identified by elemental analysis, IR (HNMR)-H-1, and (CNMR)-C-13. Surface tension experiments showed that these surfactants have higher surface activity than those without hydroxypropyl group. The values of CMC and gamma(CMC) of these surfactants have been determined.
文摘The redox behaviours of a donor-acceptor model compound. p-tricyano-ethenyl-N, N-dimethyl aniline was investigated by electrochemical and spectroelectrochemical methods. The results indicate that charge transfer between the donor(amino) and the acceptor(cyanoethenyl) groups takes place in the process of oxidation of this compound.
基金the National Natural Science Foundation of China (Grant Nos. 20473055 and 20773089)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (Grant No. 20071108-18-15)
文摘The hydrolysis mechanisms of N,N-dimethyl-N′-(2′,3′-dideoxy-3′-thiacytidine)formamidine (FA-3TC) in the gas phase and in aqueous solution were studied by use of the density functional theory B3LYP/6-31+G(d, p) method. Two possible reaction pathways in the title reaction were considered. In one pathway water attacks the C=N double bond first (path A) while in the other water attacks the C—N single bond first (path B). The calculated results indicate that the first step in both pathways is the rate-limiting process and path A is more favorable than path B in the gas phase. The effect of solvent water on the title reaction was assessed at the B3LYP/6-31+G(d, p) level of theory based on the po-larizable continuum model (CPCM). In water the first mechanism (path A) is also favored.
