Synthesis Of Novel Isoxazole Compounds And Their Antimicrobial Activity Study

This paper focus on the synthesis of a series of novel isoxazole heterocyclic compounds via the 1,3-dipolar cycloaddition reaction.Six different oximes were synthesized by the reaction of aldehydes (aliphatic and aromatic aldehydes) and hydroxylamine hydrochloride under alkaline condition, then oximoyl chlorides were synthesized via the reaction between oximes and NCS. Six oximoyl chlorides include butanhydroximoyl chloride, benzohydroximoyl chloride, 2-furohydroximoyl chloride,4-puridinylhydroximoyl chloride,2-nitrobenzoximoyl chloride,2-hydroxybenzoximoyl chloride. Two series of eight different nitrones 1, 3-dipolars were synthesized via the reaction between aldehydes (aliphatic and aromatic aldehydes) and substituted hydroxylamine hydrochloride. Eight different nitrones 1,3-dipolars include methanamine-N-butanylene-N-oxide, methanamine-N-phenylmethylene-N-oxide, methanamine-N-(2-furomethylene)-N-oxide, methanamine-N-(4-pyridylmethylene)-N-oxide,benzenamine-N-butanylene-N-oxide, benzenamine-N-phenylmethylene-N-oxide,benzenamine-N-(2-furomethylene)-N-oxid e,benzenamine-N-(4-pyridylmethylene)-N-oxide. Four novel different nitrones 1, 3-dipolars were synthesized by the reaction between different pyridine onium salts and N, N-dimethylbenzenamine, while pyridine onium salts were synthesized through the reaction between halogencarbon and pyridine via reflux in ethanol. Four novel different nitrones 1,3-dipolars include 1,4-dibenzenediamine-N, N-dimethyl-N'-isobutanylene-N'-oxide,1,4-dibenzenediamine-N,N-dimethyl-N'-phenylmethylene-N'-oxide,1,4-dibenzenediamine-N, N-dimethyl-N'-(2-furomethylene)-N'-oxide, 1,4-dibenzenediamine-N,N-dimethyl-N'-(4-pyridinylmethylene)-N'-oxide.All the novel isoxazole compounds were synthesized by the 1,3-dipolar cycloaddition between all 1,3-dipolars and olefins. There are four new parent heterocycles among them including forty-four new compounds never seen in previous references. All the novel isoxazole compounds were charactered by IR and 1HNMR. In addition, the intramolecular reaction and the regional selectivity of 1,3-dipolar cycloaddition were discussed primarily.All isoxazole compounds'antimicrobial activity was tested, the test result show that 4,5-dihydro isoxazole compounds has no antimicrobial activity,2,3,4, 5-terthydro isoxazole compounds'antimicrobial activity depends on the substituted groups. Through the antimicrobial activity test, we found that several novel compounds'antimicrobial efficient is obvious better than the frequently-used drugs exist in now market.