Shujing Yu

Design, synthesis and antifungal activities of novel pyrrole alkaloid analogs

A series of novel analogs of pyrrole alkaloid were designed and synthesized by a facile method and their structures were characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry (HRMS). The structure of compound 2a was identified by 2D NMR including heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC) and H-H correlation spectrometry (H-H COSY) spectra. Their antifungal activities against five fungi were evaluated, and the results indicated that some of the title compounds showed moderate fungicidal activities in vitro against Alternaria solani, Cercospora arachidicola, Fusarium omysporum, Gibberella zeae and Physalospora piricola at the dosage of 50 μg mL(-1). Compound 2a and 3a exhibited good activities against P. piricola at low dosage.

Microwave-assisted synthesis of some novel 1,2,3- triazoles by click chemistry, and their biological activity

Five mandipropamid analogues were designed and synthesized via “click chemistry”. The phenyl ring of mandipropamid was substituted by a 1,2,3-triazole functional group. Bioassay results indicated that some of the title compounds had moderate fungicidal activity.

Design, synthesis, and fungicidal evaluation of a series of novel 5-methyl-1H-1,2,3-trizole-4-carboxyl amide and ester analogues.

Succinate dehydrogenase inhibitors (SDHIs) are efficient fungicides that are widely used to control plant diseases caused by phytopathogenic fungi, although their effectiveness is undermined by the development of resistance across a range of different fungi. One of the most common structural features of SDHIs is their amide bond. The introduction of greater structural diversity to SDHIs is a promising strategy to delay the onset of resistance. A series of novel SDHIs containing a bioactive 1,2,3-triazole moiety have been designed and synthesized and their fungicidal and insecticidal activities evaluated. The results of these analyses show that most of the newly synthesized 1,2,3-trizole-4-carboxyl amide (ester) analogues exhibit good fungicidal activities, especially towards Sclerotinia sclerotiorum, and a structure-activity relationship study confirmed that the replacement of the amide group with an ester group had little effect on fungicidal activity, which could be provideous in terms of issues and metabolism. 1,6-Dimethyl phenyl was confirmed as the most efficient substituent of the current study when it was placed on both the amide and ester compounds. Interestingly, some of the newly synthesized compounds displayed good insecticidal activities against Culex pipiens pallens. The results of the current study show that these 1,2,3-triazole-4-carboxyl amide and ester analogues represent a new type of SDHI that could be used for the development of novel pesticides.

Synthesis, crystal structure and larvicidal activity of novel diamide derivatives against Culex pipiens

BackgroundCulex is an important mosquito as vectors for the transmission of serious diseases, such as filariasis, West Nile virus, dengue, yellow fever, chikungunya and other encephalitides. Nearly one billion people in the developing countries are at risk. In order to discover new bioactive molecules and pesticides acting on mosquito, we designed active amide structure and synthesized a series of novel diamide derivatives.ResultsA series of novel diamide derivatives were designed and synthesized. Their structures were characterized by 1 H NMR, FTIR and HRMS. The single crystal structure of compound 6n was determined to further elucidate the structure. Biological activities of these compounds were tested. Most of them exhibited higher mosquito larvicidal activity. Especially compound 6r displayed relatively good activity to reach 70% at 2 μg/mL.ConclusionA practical synthetic route to amide derivatives by the reaction of amide with another acid is presented. This study suggests that the diamide derivatives exhibited good effective against mosquito.

Novel Ultrasound-Promoted Parallel Synthesis of Trifluoroatrolactamide Library via a One-Pot Passerini/Hydrolysis Reaction Sequence and Their Fungicidal Activities

An ultrasound-promoted one-pot Passerini/hydrolysis reaction sequence has been developed for the synthesis of trifluoroatrolactamide derivatives using a diverse range of trifluoroacetophenones and isonitriles in acetic acid. Parallel synthesis in a centrifuge tube using a noncontact ultrasonic cell crusher was used in this study as an efficient method for the rapid generation of combinatorial trifluoroatrolactamide libraries, and subsequent biochemical evaluation of the resulting compounds indicated that they possessed excellent broad-spectrum fungicidal activities. N-(4-chlorophenyl)-2-(4-ethylphenyl)-3,3,3-trifluoro-2-hydroxypropanamide and N-(4-chlorophenyl)-3,3,3-trifluoro-2-hydroxy-2-(4-methoxyphenyl)propanamide, in particular, showed significant fungicidal activities against all of the fungal species tested in the current study.

Total synthesis of thaxtomin A and its stereoisomers and findings of their biological activities.

The first and facile total synthesis of thaxtomin A and its three stereoisomers has been achieved. The synthetic approach involves intramolecular nucleophilic cyclization of an amide toward a ketoamide group to produce a C-hydroxydiketopiperazine scaffold. The most amazing discovery was that each of the four stereoisomers of TA exhibits different phytotoxic, fungicidal, and antiviral activities.

Larvicidal Activity and Click Synthesis of 2-Alkoxyl-2-(1,2,3-Triazole-1- yl)Acetamide Library

Heterogeneous copper-in-charcoal-catalyzed click synthesis in 96-well polypropylene filter plates is an efficient method for the rapid generation of sufficient pure 2-alkoxyl-2-(1,2,3-triazole-1-yl) acetamide derivatives library by simple filtration, which directly assay the products for larvicidal activity against mosquitoes. In this procedure, copper nanoparticles on charcoal were arrayed into each well on a 96-well plate, reagents were delivered using a pipette gun, and a constant temperature shaker bath was used to complete the click reaction in 24-72 hours under temperature-controlled conditions. The results of bioassays indicated that the target compounds possessed excellent larvacidal activities against mosquitoes. In particular, the larvacidal activities against mosquitoes of compounds 8[2,3] and 8[7,1] at 2 µg.mL⁻¹ were 100% and 73% respectively.

Synthesis and characteristics of (Hydrogenated) ferulic acid derivatives as potential antiviral agents with insecticidal activity

BackgroundPlant viruses cause many serious plant diseases and are currently suppressed with the simultaneous use of virucides and insecticides. The use of such materials, however, increases the amounts of pollutants in the environment. To reduce environmental contaminants, virucides with insecticidal activity is an attractive option.ResultsA series of substituted ferulic acid amide derivatives 7 and the corresponding hydrogenated ferulic acid amide derivatives 13 were synthesized and evaluated for their antiviral and insecticidal activities. The majority of the synthesized compounds exhibited good levels of antiviral activity against the tobacco mosaic virus (TMW), with compounds 7a, 7b and 7d in particular providing higher levels of protective and curative activities against TMV at 500 μg/mL than the control compound ribavirin. Furthermore, these compounds displayed good insecticidal activities against insects with piercing-sucking mouthparts, which can spread plant viruses between and within crops.ConclusionsTwo series of ferulic acid derivatives have been synthesized efficiently. The bioassay showed title compounds not only inhibit the plant viral infection, but also prevented the spread of plant virus by insect vectors. These findings therefore demonstrate that the ferulic acid amides represent a new template for future antiviral studies.

Design, synthesis, and fungicidal activity of novel carboxylic acid amides represented by N-benzhydryl valinamode carbamates

Carboxylic acid amide (CAA) fungicides are an important class of agricultural fungicide with oomycete activity and low toxicity toward mammalian cells. To find CAA analogues with high activity against resistant pathogens, a series of substituted N-benzhydryl valinamide carbamate derivatives were designed and synthesized by introducing substituted aromatic rings into valinamide carbamate leads. Bioassays showed that some title compounds exhibited very good in vitro fungicidal activity against Phytophthora capsici and in vivo fungicidal activities against Pseudoperonospora cubensis. Topomer CoMFA was performed to explore the structure-activity relationship on the basis of the in vitro data. The dimethoxy substituted aromatic analogue 9e was found to display higher in vitro fungicidal activity against Phytophthora capsici than iprovalicarb but lower activity than mandipropamid, and higher in vivo fungicidal activity against Pseudoperonospora cubensis than dimethomorph at a dosage of 6.25 μg mL(-1).

Synthesis and fungicidal activity of novel aminophenazine-1-carboxylate derivatives.

A series of novel 6-aminophenazine-1-, 7-aminophenazine-1- and 8-aminophenazine-1-carboxylate derivatives were synthesized by a facile method, and their structures were characterized by (1)H NMR, (13)C NMR and high-resolution mass spectrometry. Some unexpected byproducts V-7b-V-8d were noticed and isolated, and their structures were identified by 2D NMR spectra including heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (Hmbc) and H-H correlation spectrometry (H-H COSY) approach. Their fungicidal activities against five fungi were evaluated, which indicated that most of the title compounds showed low fungicidal activities in vitro against Alternaria solani, Cercospora arachidicola, Fusarium omysporum, Gibberella zeae, and Physalospora piricola at a dosage of 50 microg mL(-1), while compounds IV-6a and IV-6b exhibited excellent activities against P. piricola at that dosage. Compound IV-6a could be considered as a leading structure for further design of fungicides.