Synthetic Routes for Phytoene Desaturase Inhibitors

Major Synthetic Routes for Phytoene Desaturase Inhibitors 

Diflufenican is synthesized by nucleophilic substitution of 2-chloronicotmic acid with 3-hydroxybenzotrifluoride and further reaction with thionyl chloride and 2,4-difluoroaniline to the final product [39]. 

Flurochloridone is made by copper chloride-catalyzed cyclocondensation of N-allyl-(3-trifluormethylphenyl)dichloroacetamide 49 [34]. 

Fluridone is accessible in two ways. l-(3-Trifluormethylphenyl)-3-phenyl-2-propanone (50) is reacted with ethyl formate in the presence of a base to yield the diformyl derivative 51, which is cydized with methylamine to the final product. Alternatively, 50 is condensed with formamidine acetate in the presence of formamide to the 4(lH)-pyridone intermediate 52 and then methylated to give fluridone [34]. 

Flurtamone is prepared by cyclization of 4-phenyl-2-(3-trifluormethylphenyl)-3-oxobutyronitrile (53) with bromine in the presence of acetic add and methylation to the final heterocycle [34]. 

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