[CH3:1][C:2]1[CH:7]=[C:6]([CH:8]=C)[N:5]=[C:4]([NH:10][C:11](=[O:13])[CH3:12])[CH:3]=1.[O:14]=[O+][O-].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>CO.ClCCl>[CH:8]([C:6]1[N:5]=[C:4]([NH:10][C:11](=[O:13])[CH3:12])[CH:3]=[C:2]([CH3:1])[CH:7]=1)=[O:14]5.0 g N-(4-methyl-6-vinyl-pyridin-2-yl)-acetamide (compound F5) are dissolved in a mixture of each 200 ml methanol and dichloromethane and cooled to −80° C. Subsequently, ozone is passed into the solution (flow 20-25 l/h ozone). After 5 min ozone treatment is stopped. Thereafter, nitrogen is applied for 5 min and 7.44 g of triphenylphosphane are added while stirring is continued. The solution is allowed to warm up to r.t. Subsequently, the volatile components are removed in vacuo and the residue is purified by chromatography on silica gel (eluent cyclohexane/ethyl acetate 3:1) to afford 2.72 g of the title compound as colourless solid. M.p. 202° C. GC-MS: 178.2 (M+). TLC: Rf=0.50 (cyclohexane/ethyl acetate 1:1). [Remark: Occasionally remaining traces of triphenylphosphine oxide can be removed by dissolving crude product in ethyl acetate followed by cooling to precipitate triphenylphosphine oxide.]
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