Oxadiazine Derivatives and Their Use as Pesticides

Dyker etal, US Patent 6,414,158 (July 2, 2002) Assignee Bayer Aktiengesellschaft Utility Pesticides 

Benzyl (2-t-butoxycarbonyl-2-methyl-l-propylhydrazyl)-carbonyloxy-acetate 

For 1 hour CO2 was introduced into a suspension of Ce2C03 (22.8 g) and l-t-butoxycarbonyl-2-methyl-l-propylhydrazine (6.55 g) dissolved in 140 ml DMF. Thereafter, benzyl bromoacetate (8.02 g) was added drop wise, CO2 introduction continued for an additional 45 minutes, and the mixture stirred overnight. The mixture was poured into 300 ml semi-saturated NaCl solution, extracted 3 times with 150 ml EtOAc, dried, and concentrated. The mixture was purified by chromatography using silica gel with cyclohexane/EtOAc, 5 1, and the product isolated in 67% yield. H-NMR data supplied. 

At 0°C trifluoroacetic acid (16.9 g) was added to the product from Step 1 (6.65 g) dissolved in 50 ml CH2CI2, stirred 3 hours at 0°C, and then warmed to ambient temperature overnight. The mixture was concentrated, the residue dissolved in 300 ml EtOAc, washed with NaHC03 and brine solutions, and dried. The product was isolated in 100% yield after vacuum evaporation of solvent. H-NMR data supplied. 

The product from Step 2 (4.36 g) was dissolved in 100 ml EtOAc, 10% palladium on carbon (100 mg) added, and the mixture hydrogenated at 1 bar at ambient temperature. Thereafter, the mixture was filtered through celite, concentrated, and the product isolated in 100% yield. H-NMR data supplied. 

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