摘要：
Phytoalexins are low-molecular-weight chemicals that immune systems of plants produce and accumulate in response to infections, especially those of fungal origin. Although their content is not high in plants, yet they have shown unique fungicidal activity and played an important role in the defence system of plants. In searching for novel environmentally benign fungicides with high activity, the structures of flavanone derivatives, one of the most important phytoalexins groups, have been modified via bioisosteric substitution and a series of 2-heteroaryl-4-chromanones were designed and synthesized. They showed good fungicidal activities against rice blast disease, Pyricularia grisea (Sacc). Their IC50 values were tested in vitro and the relationship between structure and fungicidal activity was analyzed quantitatively using a Hansch-Fujita approach. The results showed that hydrophobicity was very important for fungicidal activity and there is apparently an optimum hydrophobic property for the molecules at a log P-ow value of about 2.7. In addition, the results indicated that electronic effects played an important role in binding with the receptor and that the C=O group was probably a electron-accepting site. The quantitative structure-retention correlative equation of the tide compounds was also established. (C) 2002 Society of Chemical Industry.
摘要：
A series of diheterocyclic compounds containing 1,2,4-triazolo [1,5-a]pyrimidine and 1, 3,4-oxadiazole were designed and synthesized starting from 2-mercapto-5,7-dimethyl-1,2,4-triazolo [1,5-a] pyrimidine. The structure of all compounds prepared were confirmed by 1H NMR spectroscopy and elemental analysis. The preliminary bioassay indicated that the title compounds displayed good fungicidal activity against Rhizoctonia solani.
作者机构：
[Yang, GF] Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Peoples R China.;Nankai Univ, Inst Elementoorgan Chem, Tianjin 300071, Peoples R China.
通讯机构：
[Yang, GF] C;Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Peoples R China.
摘要：
The regioselective addition reaction of 5-amino-1,2,4-triazoles and its pyrazole analogues 1 with arylsulfonyl isocyanates were described. Experimental results showed that the addition reaction of 1 with arylsulfonyl isocyanates at room temperature took placed at the 5-position amino group and adducts 4 were obtained, however, the reaction proceeded at 1-N at the presence of sodium hydride to give products 5, which suggested that the amino nitrogen at C-5 is more nuclophilic than 1-N in this reaction system. In addition, molecular mechanic calculations were applied to explain the regioselectivity.
作者机构：
[Yang, GF] Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Peoples R China.;Nankai Univ, Inst Elementoorgan Chem, Tianjin 300071, Peoples R China.
通讯机构：
[Yang, GF] C;Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Peoples R China.
摘要：
The crystal structure of the title compound has been determined by single crystal X-ray diffraction analysis. C15H14N4O3, M-r = 298. 30, monoclinic, space group P2(1)/n, a = 9. 483 (9), b = 11. 078 (9), c = 13. 700 (9) Angstrom, beta = 100. 19 (7)degrees, V = 1417 (4) Angstrom(3), Z = 4, D-x = 1. 399 g. cm(-3), mu = 0. 0942 mm(-1); F(000) = 624, final R = 0. 074 and R-w = 0. 074 for 1502 observed reflections [I greater than or equal to 3 sigma(I)]. The results show that all ring atoms in the triazolopyrimidinyl moiety were coplanar with strong tensile force, which might be an important active site.
作者机构：
[Yang, GF] Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Hubei, Peoples R China.;Nankai Univ, Inst Elementoorgan Chem, Tianjin 300071, Peoples R China.
通讯机构：
[Yang, GF] C;Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Hubei, Peoples R China.
关键词：
ALS inhibitors;QSAR;sulfonylureas;herbicides
摘要：
The quantitative relationship between the structures of 20 sulfonylureas and their herbicidal activities against rape was analyzed using physicochemical parameters and regression analysis. The results showed that the electronic properties of the molecules are the dominant factor to the activity and there is apparently an optimum electronic property (∑σ or pKa) for the molecules to fit the receptor. Combined with the previous QSAR results for herbicidal triazolopyrimidine-2-sulfonamides, we can conclude that the structure-activity relationships of these two sets of compounds are identical, which suggested that these two sets of compounds acted on the same target site.
作者机构：
[Yang, GF] Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Peoples R China.;Nankai Univ, Inst Elementoorgan Chem, Tianjin 30071, Peoples R China.
通讯机构：
[Yang, GF] C;Cent China Normal Univ, Inst Organ Synth, Wuhan 430079, Peoples R China.
摘要：
Some novel phosphonate derivatives containing triazolo[1,5-a]pyrimidine moieties have been synthesized in good yields by the nucleophilic substitution between alpha-hydroxyphosphonates and 2-methanesulfonyl-1,2,4-triazolo[1,5-a]pyrimidines. The structure has been confirmed by elementary analyses, NMR and MS. The results of preliminary bioassay indicates that the title compounds possess selective herbicidal activity.
