Toluene → 7,8,9,10-Tetrahydro-8-methyl-2,3-bis(phenylmethoxy)-pyrido[4,3-f]quinoxalin-6-yl phosphonic acid diethyl ester

Participants

Reaction Steps

A solution of the product from Example 100 (1.83 g, 3.73 mmol) was dissolved in dry toluene and treated with diethylphosphite (0.72 mL, 5.59 mmol), triethylamine (1.56 mL, 11.2 mmol) and tetrakis (triphenylphosphine)palladium (0) (0.44 g, 0.37 mmol). The resulting solution was heated to reflux under a nitrogen atmosphere for 48 hours. The reaction mixture was concentrated and the residue was dissolved in CHCl3 and washed with saturated aqueous NaHCO3 solution. The organic phase was dried, filtered and concentrated. The residue was purified by chromatography (SiO2, gradient elution EtOAc then 5:1 EtOAc/EtOH). The material obtained was dissolved in hot iPr2O, filtered and concentrated. The residue was then broken up in a mall amount of iPr2O and the solid collected by filtration and dried under vacuum to give the title compound as a yellow solid (0.74 g, 36% yield), mp=104° C. The filtrates were concentrated to give an additional 0.77 g of the title compound.

Provenance & Evidence