Quantitative structure—activity studies of some octopaminergic agonists against Periplaneta americana

The quantitative relationship between the structure of 2-(arylimino) thiazolidines (AITs), arylethanolamines (AEAs) and 2-(arylalkylamino)-2-thi-azolines (AATs) and their octopamine (OA)-agonist activities against the ventral nerve cord of American cockroach, Periplaneta americana L., was analysed using reported physicochemical parameters and regression analysis. The electronic nature of a substituent was the most important factor for AAT, followed by the hydrophobic effects: the more electron-donating and the more hydrophobic the substituent, the greater the activity. The hydrophobic nature of a substituent in AEA was the most important factor, followed by the steric effects: the more hydrophobic the substituent, the greater the activity. The more electron-donating the substituent of AIT, the greater the activity.     

美洲大蠊和东亚飞蝗的耐缺氧力及其比较

研究并比较了美洲大蠊和东亚飞蝗在接近真空和充满CO2的环境下的耐缺氧力。结果表明：美洲大蠊和东亚飞蝗在0.06pa的真空泵中都能存活,在2～10min后其生理活动会不断减弱,直到假死或静止不动,但不会死亡,90～120min后两者的生理活动逐渐恢复,但都比正常状态下弱,生理活动都呈现反抛物线的规律,且在同一时间东亚飞蝗比美洲大蠊的生理活动要弱;美洲大蠊在充满CO2的密闭瓶中存活的时间比东亚飞蝗要长,将不同程度缺氧处理后的试虫置于空气中后,美洲大蠊恢复正常生理活动的能力和恢复后的活动强度明显比东亚飞蝗强。说明美洲大蠊和东亚飞蝗都有较强的耐缺氧力,但美洲大蠊的耐缺氧力更强。     

Dimethoxypyrimidines as novel herbicides. Part 4. Quantitative structure–activity relationships of dimethoxypyrimidinyl(thio)salicylic acids

The activity of a number of O-(4,6-dimethoxypyrimidin-2-yl)salicylic acids and their thio analogs inhibiting acetolactate synthase (ALS) preparation was measured. The effects of substituents on the salicylic-benzene ring on the inhibitory activity were analyzed quantitatively with physicochemical substituent parameters. For 6-substituted (thio)salicylic acids, the activity was shown to vary parabolically with the ‘intramolecular’ steric parameter ( E_s ). In addition, the higher steric dimension of substituents in terms of the STERIMOL width or length parameter lowered the activity. The field-inductive electron-withdrawing property of the 6-substituents in terms of the Swain–Lupton–Hansch F was favorable for the activity of salicylic acid series. In 5-substituted salicylic acids, the activity was increased by electron-donating substituents with smaller size. The relationships between ALS inhibitory and herbicidal activities were also analyzed with some weed species. Both pre- and post-emergence activities against barnyard grass, Echinochloa crus-galli, were linearly related to the ALS inhibitory activity after allowing for the hydrophobic factor that may contribute to the transport processes. Those against two broad-leaved weed species, Polygonum convolvulus and Abutilon theophrasti were linearly related to the in-vitro activity with no significant participation of the hydrophobic factor. © 1998 SCI     

Synthesis and structure–activity relationships for anticipated molluscicidal activity of some 2-amino-5-substituted pyridine derivatives

A series of 2-amino-5-substituted pyridine derivatives was synthesized and their molluscicidal activity against white garden, Theba pisana (Müller), and brown garden, Helix aspersa (Müller), snails was investigated by two methods of application. Some of these compounds showed strong activity under laboratory conditions against the two types of snail. T pisana was more sensitive to the tested compounds than H aspersa. The most effective compounds were 2-amino-5-(benzotriazole-1-ylmethyl)-3-methylpyridine, 2-amino-5-[1-(benzotriazole-1-yl)nonyl]-3-methylpyridine and 2-[(1,2,4-triazole-1-ylmethyl)amino]-3-methylpyridine which exhibited high molluscicidal activity. The toxicity results are discussed in relation to the chemical structures. © 1999 Society of Chemical Industry     

Effect of substituents at the 5-position of the pyridine ring of imidacloprid on insecticidal activity against Periplaneta americana

The insecticidal activities of imidacloprid derivatives with a wide range of substituents at the 5-position on the pyridine ring against American cockroaches, Periplaneta americana (L.), were measured by injection with and without synergists propyl 2-propynyl phenylphosphonate and piperonyl butoxide. The log(1/MLD) value (MLD = minimal lethal dose in mol) without synergists was 7.96 for the methyl derivative, and the values were lower for other derivatives. Synergists enhanced the potencies of all the compounds tested. Considering these compounds and those with other substituents at this position, the region for maximum activity was predicted to be in the conjunction of the pyridyl 6-chlorine atom with a lipophilic small group in the 5-position.     

Novel acetylcholinesterase inhibitors: Synthesis and structure–activity relationships of phthalimide alkyloxyphenyl N,N-dimethylcarbamate derivatives

Based on the multiple binding sites of acetylcholinesterase (AChE), a series of AChE inhibitors: phthalimide alkyloxyphenyl N,N-dimethylcarbamate were designed and synthesized. AChE inhibitory activity and structure–activity relationship of the compounds were researched also. The influence of structural variations on the inhibitory potency was carefully investigated by modifying different alkyloxy chain length and position between phthalimide and phenyl N,N-dimethylcarbamate (PDM). The biological properties of the series were investigated by considering the activity on isolated enzyme. Some of the newly synthesized derivatives, when tested on isolated AChE from head of housefly (Musca domestica), were more active than PDM. The compounds J1, J2 and K1–K8 demonstrated higher inhibitory activity (5- to 404-fold) for AChE than that of PDM. In particular, compound K1 displayed the best AChE inhibition (404-fold higher than PDM), which suggested that phthalimide group of K1 strongly bound at the residues lining the gorge while phenyl N,N-dimethylcarbamate bound at the catalytic site.