Synthesis and antibacterial activity against ralstonia solanacearum for novel hydrazone derivatives containing a pyridine moiety

Abstract

BackgroundRalstonia solanacearum, one of the most important bacterial diseases on plants, is a devastating, soil-borne plant pathogen with a global distribution and an unusually wide host range. In order to discover new bioactive molecules and pesticides acting on tobacco bacterial wilt, we sought to combine the active structure of hydrazone and pyridine together to design and synthesize a series of novel hydrazone derivatives containing a pyridine moiety.ResultsA series of hydrazone derivatives containing a pyridine moiety were synthesized. Their structures were characterized by 1 H-NMR, 13 C-NMR, IR, and elemental analysis. The preliminary biological activity tests showed that compound 3e and 3g exhibited more than 80% activity against Ralstonia solanacearum at 500 mg/L, especially compound 3g displayed relatively good activity to reach 57.0% at 200 mg/L.ConclusionA practical synthetic route to hydrazone derivatives containing a pyridine moiety by the reaction of intermediates 2 with different aldehydes in ethanol at room temperature using 2-chloronicotinic acid and 2-amino-5-chloro-3-methylbenzoic acid as start materials is presented. This study suggests that the hydrazone derivatives containing a substituted pyridine ring could inhibit the growth of Ralstonia solanacearum.

Synthesis and antifungal activities of novel nicotinamide derivatives containing 1,3,4-oxadiazole

“…However, the synthetic method showed in Scheme 2 had several shortcomings, which included long steps, poor stability of 2-chloronicotinoyl chloride, low yields and long reaction times for preparation of 10a to 10d . A single-step alternative protocol with a short reaction time and high yields (>90%) carried out at room temperature in acetonitrile was thus employed by treatment of 2-chloronicotinic acid ( 1 ) with 2-amino-sbustitutedbenzoic acid ( 2a - 2d ) in the presence of pyridine and methanesulfonyl chloride [14,25,28,29]. The further reaction of substituted-2-(2-chloropyridin-3-yl)-4 H -benzo[ d ] [1,3]oxazin-4-one ( 3a - 3d) with 80% hydrazine hydrate could carry out readily in 1 h at room temperature to give substituted- N -(2-(hydrazinecarbonyl) phenyl) nicotinamide ( 4a - 4d) [14].…”

Synthesis, antifungal and antibacterial activity for novel amide derivatives containing a triazole moiety

“…Mepronil, flutolanil, and tiadinil are known for their ability to protect certain plants from severe diseases and pests (Figure 1). In our recent publications [15,16], several pyrazole amide derivatives containing a hydrazone moiety have been synthesized and tested for their antifungal activity. The synthesized compounds exhibited antifungal activity against Fusarium oxysporum and Cytospora mandshurica , with inhibitory rates ranging from 40.82% to 50.32%.…”

Synthesis and antifungal activity of novel pyrazolecarboxamide derivatives containing a hydrazone moiety

“…Intermediates 4 were prepared using 1,3-dimethyl-1  H -pyrazol-5(4  H )-one as starting materials. 1,3-dimethyl-1  H -pyrazol-5(4  H )-one was firstly subjected to Vilsmeier-Haack chloroformylation using N,N -dimethylformamide (DMF) and phosphorus oxychloride (POCl 3 ) to yield 5-chloro-1,3-dimethyl-1  H -pyrazole-4-carbaldehyde 1 [9], which was further oxidized by potassium permanganate and following chlorinated with thionyl chloride (SOCl 2 ) to provide the intermediates 3 , then intermediates 4 were prepared by treating 5-chloro-1,3-dimethyl-1  H -pyrazole-4-carbonyl chloride with 2-amino-3-methylbenzoic acid or 5-chloro-2-amino-3-methylbenzoic acid in CH 2 Cl 2 in present of triethylamine in good yields, 2-(5-chloro-1,3-dimethyl-1  H -pyrazol-4-yl)-8-methyl-4  H -benzo d [1,3]oxazin-4-one 5 can be easily synthesized by reaction of acetic anhydride with 4 in excellent yield [21], however, it also can be prepared in a single step by the reaction of 3 with substituted 2-amino-3-methylbenzoic acid as describing in the literature [21,22]. Finally, compounds 6 were conveniently obtained with excellent yield (>90%) by treatment of 5 with 80% hydrazine hydrate, subsequent treatment of 6 with different ketones and aldehydes (or hemiacetals) in ethanol at room temperature afforded the desired compounds ( 7a to 7s ) with excellent yields.…”

“…Some of the compounds containing hydrazone substructure have been commercialized as pesticides (such as benquinox, diflufenzopyr, and ferimzone) (Figure  1). In our recent publications [21,22], several hydrazone derivatives have been synthesized and tested for their insecticidal activity and antibacterial activity, some of the hydrazone derivatives exhibited notable insecticidal activity against Plutella xylostella Helicoverpa armigera Culex pipiens pallens Laphygma exigua Spodoptera litura Nilaparvata lugens and Rhopalosiphum maidis [21], and some of the hydrazone derivatives containing a pyridine moiety possessed good antibacterial activity against Ralstonia Solanacearum [22]. …”