Synthesis Of Tabtoxinine-β-lactam And Study Of Cyclization Reaction By PIFA

Tabtoxin is a dipeptide exotoxin produced by Pseudomonas tabaci, the organismresponsible for the wildfire disease of tobacco plants. When hydrolyzed by peptidasesin vivo, this exotoxin releases tabtoxinine-β-lactam, which inhibits glutaminesynthetase, causing chlorosis and death of the tobacco plants[1].In this thesis, a new synthetic route of Tabtoxinine-β-lactam was developed.Before the synthesis of Tabtoxinine-β-lactam, a model compound 15 was designed.The epoxide was prepared by oxidation of olefin with mCPBA. Then the epoxideopened and cyclized to key intermediate 4-benzyl-4-hydroxyisoxazolidin-3-one 6.Compound 6 was expected to react with triphenylphospine or triethylphosphite toobtain the target product 15, and apply to synthesize Tabtoxinine-β-lactam 2. Thissynthesic route is shorter than the reported methods.And in this thesis, the cycling reaction by PIFA was studied. Target productethyl 1-methoxy-2-oxo-1,2,3,4-tetrahydroquinoline-3-carboxylate 18d was designed,which starting from compound diethyl 2-benzylmalonate 10。Finally, a species of newcompounds 18 were synthesized by this cyclization method. Their structures wereconfirmed by 1H NMR spectra.