Synthesis And Bioactivity Of Phosphoramidothionate From α-Pinene Derivatives

α-Pinene is the essential component in turpentine which is one of abundantresources of Guangxi Zhuang Autonomous Region. The wide utilization ofα-pinene are mainly on flavors and solvents now. The research project in thispaper is focus on the field of insecticide that is significant to increase the yieldof crop in agriculture. As a new compound the target moleculeO, O-diethyl-N-(cis-3-acetyl-2, 2-dimethylcyclobutyl)ethanoylphosphoramido-thionate is synthesized fromα-pinene and O,O-diethyl chlorothiophosphate.α-Pinene is reproducible and abundant resource, and O, O-diethylchlorothiophosphate has good bioactivity. The target molecule is hopeful to be ahigh efficiency and low toxicity insecticide. This will be very significant for thestudy of new insecticide. Two schemes were designed to synthesize the targetmolecule.(1)Scheme 1: (-)-pinonamide combined with diethyl chlorothiophosphate.Scheme 1 started fromα-pinene and through the intermediate pinonic acid and(-)-pinonamide. By the orthogonal experiment, the optimal conditions for synthesis of pinonic acid were obtained as follows: ammonium sulphate 2.8g,emulsifier sodium dodecylsulfate 0.3g (α-pinene 10g and potassiumpermanganate 24.5g were constant in the experiments), reaction temperature30～35℃, reaction time 4h. The yield ofpinonic acid amounted to 74%.(-)-Pinonamide was synthesized fromα-pinene through the reactions ofoxidation, chlorination and ammoniation. There are no reports about phosphorustrichloride as a chlorination agent for preparation of pinonoyl chloride. Sophosphorus trichloride was used as a chlorination agent in this paper. Theexperimental results showed that the optimal conditions for synthesis of(-)-pinonamide were: molar ratio of phosphorus trichloride to pinonic acid0.83:1, phosphorus trichloride in 1, 2-dichloroethane was added dropwise topinonic acid in 1, 2-dichloroethane, reacted at ambient temperature for 3h. Thenthe reaction solution was added dropwise to 1,2-dichloroethane while saturatedwith anhydration ammonia at 10～15℃for 1h. The yield of (-)-pinonamideamounted to 86.7%.The target molecule can't be obtained from scheme 1 but the dehydrationproduct of (-)-pinonamide had been formed.(2)Scheme 2: pinonoyl chloride combined with diethyl phosphoramido-thionate. The target molecule was successful prepared by the means of hydrogensulfide method. The target molecule was analyzed and characterized with TLC,IR, UV, LC-MS, ¹H-NMR and ¹³C-NMR methods. The conditions for synthesisof phosphoramidothionate were investigated as follows: molar ratio of diethyl phosphoramidothionate to pinonic acid 1:1, 45℃, 4h. The yield ofphosphoramidothionate amounted to 21.6%. A HPLC method was developed toanalyze the target product. The synergistic activity of the mixture of the targetproduct and trichlorfon to Crocidolomia pavonana(Fabricius) was evaluated byusing the method of co-toxicity coefficient(CTC). The toxicity test showed thatthe mixtures of the target product and trichlorfon have significant synergism toCrocidolomia pavonana(Fabricius), and the mixtures(3:7)had highersynergistic activities, their CTC were 226.