混合含氟对甲苄醇类菊酯的合成及其杀虫活性

报道了4种混合含氟对甲苄醇类拟除虫菊酯的新化合物,即三氟甲基氯菊酸、(±)-cis-二氯菊酸、(±)-trans-二氯菊酸、( )-trans-第一菊酸的含氟对甲苄酯的合成.生物活性测试的结果表明这些化合物对淡色库蚊四龄孑孓显示出较高的杀虫活性.     

第二菊酸类混合含氟苄酯的合成及其杀虫活性

>报道了第二菊酸及其2(3)-氟-4-甲氧甲基苄酯和2(3)-氟-4-甲基苄酯的合成, 生物活性测试的结果表明这两种新化合物对淡色库蚊四龄孑孓显示出较高的杀虫活性.     

两种卤代菊酸含氟对甲氧甲基苄酯的合成及其杀虫活性

报道了两种含氟对甲氧甲基苄酸类拟除虫菊酯新化合物，即三氟甲基氯菊酸含 氟对甲氧甲基苄酯和二溴菊酸含氟对甲氧甲基苄酯的合成。生物活性测试的结果表 明该化合物对家蝇显示出较高的杀虫活性和较低的抗性。     

(R)-α-苯乙胺拆分全顺式-3-N-叔丁氧羰基氨基-5-甲氧羰基环己基甲酸

以光学活性(R)-α-苯乙胺(1)为拆分剂,将cis,cis-3-N-叔丁氧羰基氨基-5-甲氧羰基环己基甲酸[(±)-2]拆分为cis,cis-(-)-2,其结构经1H NMR和13C NMR确证。最佳拆分条件为:以丙酮为溶剂,n(1)∶n[(±)-2]=1.0∶1.0,拆分效率34.1%。     

偏氯含氟菊酯异构体的合成及其杀虫活性

α-氰基-4-氟-3-苯氧苄基-2,2-二甲基-3-(-2-氯乙烯基)-环丙烷羧酸酯(简称偏氯含氟菊酯)是一类新型拟除虫菊酯.报道了它的12个异构体的合成.生物活性测试结果表明,这些异构体对淡色库蚊四龄孑孓都显示出杀虫活性,其中(αS,1R,3R)-cis-E-异构体5aes和(αS,1R,3R)-cis-Z-异构体5azs显示出比溴氰菊酯更高的杀虫活性.     

2-(N''-二氯菊酰脲基)嘧啶衍生物的合成与杀虫活性测定

采用活性基团拼接法,以酰基脲为骨架,把二氯菊酸与取代-2-氨基嘧啶环连接起来,合成了7种未见文献报道的2-(N'-二氯菊酰脲基)嘧啶衍生物,其结构经IR,1HNMR,元素分析得到确证,初步的生物活性测试表明部分化合物具有一定的杀虫活性.     

2,2-二甲基-3-(2''-氯3'',3'',3''-三氟丙烯基)环丙烷羧酸-α-取代基对甲氧甲基苄酯的合成及活性研究

本文对氟氯氰菊酯(Cyhalothrin)的几条全合成路线进行了研究. 并对其构型和生物活性的关系进行了探讨. 并将(+/-)cis酸进行拆分. 所合成的脂进行昆虫药效测试, 结果表明它们都有杀虫活性, 但以(+)cis构型为最佳.     

α-羟基-1-萘乙酸的合成与拆分

以1-萘甲醛为原料,三乙基苄基氯化铵为相转移催化剂,合成了消旋的α-羟基-1-萘乙酸[(±)-2],收率51.4%.以光学活性(R)-( )-N-苄基苯乙胺为拆分剂,拆分(±)-2得(-)-2,拆分率45.5%.     

酶催化拆分制备手性2-氯-1-(2,4-二氟苯基)乙醇及 光学活性抗真菌药物的合成

用Pseudomonas stutzeri脂肪酶催化转酯化反应动力学拆分外消旋体法制备高对映体纯的手性2-氯-1-(2,4-二氟苯基)乙醇, 得到95.8% ee值的(R)-异构体和94.5% ee值的(S)-异构体, 以此手性醇为关键中间体合成了4种具有抗真菌活性的光学活性化合物α-氯代苄氧基-β-(1-咪唑基)-2,4-二氟乙苯硝酸盐. 纸片扩散法测试体外抗真菌活性结果表明, 对各种念珠菌(Candida species) (R)-5a和(R)-5b具有与氟康唑相当的抗菌活性, 特别是对氟康唑耐药的烟曲霉菌(Aspergillus fumigatus), 5a, 5b及其两种光学活性异构体均有优异的抗菌活性, 而且(R)-异构体的活性明显高于(S)-异构体和外消旋体.     

二氯菊酯光学异构体的分析

利用顺式二氯菊酯和反式二氯菊酸的溶解度不同及pKa值的差异，分离二氯菊酸中的顺式体和反式体，可取得较好的效果（反式二氯菊酸收率83．7％，顺式二氯菊酸收率88．9％），以S（－）－α－甲基苄胺为拆分剂，对顺式－2，2－二甲基－3－3（2，2－二氯乙烯基）环丙烷羧酸酯（俗称顺式二氯菊酯）类杀虫剂合成中间体0顺式－2，2－二甲基－3－（2，2－二氯乙烯基）环丙烷羧酸（俗称顺式二氯菊酸）进行拆分，可以得到其旋光异构体；其旋光异构体与S（－）－α－甲基苄胺衍生化，生成相应的酰胺；经TLC纯化后，以外消旋顺式二氯菊酸酰胺作为对照，用HPLC检测其旋光异构体的光学纯度；结果显示，顺式－R（＋）－2，2－二甲基－3－（2，2－二氯乙烯基）环丙烷羟酸光学纯度为93．7％，顺式－S（－）－2，2－二甲基－3－（2，2－二氯乙烯基）环丙烷羧酸光学纯度为81．8％，对反式二氯菊酸的光学纯度分析，可采用类似的方法：经顺，反分离，旋光异构体拆分获得的高效中间体，再进行后序合成，其顺反比，旋光纯度不变。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.