Synthesis Of Picoxystrobin And Application Of Related Intermediates

Picoxystrobin is a sort of methoxyacrylate fungicides which have low toxicity, high efficiency and broad spectrum, and it has just come into market abroad. With the features of unique pharmacological activities and mechanisms, it has paid people’s great attention especially. And there has no domestic manufacturer for picoxystrobin.On the basis of the related literature, we explored the new synthetic route of pyraclostrobin and effectively optimized the reported process. With indene, formic acid and hydrogen peroxide as starting materials, 2-indanone was synthesized via epoxidation,esterification and thermal elimination in yield of 63.9%;3-isochromanone was achieved by baeyer-villiger oxidation of 2-indanone in yield of 82.4%;and then 4-(Methoxymethylene)-3-isochromanone was obtained from 3-isochromanone via formylation and methylation in yield of 78.2%; 4-(Methoxymethylene)-3-isochromanone was treated with thionyl chloride and methanol to form 3-Methoxy-2-(2-(chloromethyl)phenyl)acrylic acid methyl ester which needn’t to be purified, following directly condensate with 2-hydroxy-6-trifluoromethylpyridine to get the target compound which was purified by recrystallization in yield of:78.2%. The total yield of synthetic route is 28.9%.6-(trifluoromethyl)-Pyran-2-one was prepared from trifluo- roacetic anhydride and tigloyl chloride as starting material by the new method of cyclization, and then 2-hydroxy-6-trifluoromethylpyridines as the key intermediate of picoxystrobin was obtained from 6-(trifluoromethyl)-Pyran-2-one via ammonification, in yield of 55.2%. While we applied 2-hydroxy-6-trifluoromethylpyridines to other aspects, we observed that it could be treated with phosphorus pentachloride to form 2-chloro-6-trifluoromethylpyridines under the catalysis of phenylphosphonic dichloride. In our work, we also developed a system for halogenation which can be applicable to a wide range of phenols, and we got some positive results.In addition, we investigated the chloridization reaction of aromatic aldehydes using phosphorus pentachloride. The results showed that we can afford the corresponding dichloromethylated aromatics or trichloromethylated aromatics by controlling the reaction condition.The structures of the above compounds and some intermediates were characterized by means of IR,1HNMR,HRMS.