反应详情

温度

-15 °C

42 (42.0 g, 0.22 mol) was added portionwise as a finely ground powder over 1 h to a solution of concentrated sulphuric acid (28 mL) in 100% nitric acid (140 mL) at −20° C. During the addition, the reaction temperature was maintained at around −15° C. The reaction mixture was stirred at −5° C. for a further 40 min, then poured into to ice/water (1 L) and extracted rapidly with toluene (2×). The organic phase was washed successively with 0.25 M NaHCO3 aq. water and brine, dried (Na2SO4) and evaporated to dryness to give crude product (19.8 g) as a yellow oil, which was shown by NMR to contain ˜60% nitro-compounds. Purification of 8 g of this material by column chromatography (three times, SiO2, first eluting with 1:9 EtOAc:cyclohexane, then with 3:7 EtOAc:cyclohexane and finally with 1:1 EtOAc:cyclohexane) gave 43 (2.53 g) in (˜80% purity) together with 2-hydroxy-3-methoxy-4-nitrobenzaldehyde (˜10%). The product was used as such in the next step.

1. additionDuring the addition
2. extractionextracted rapidly with toluene (2×)
3. washThe organic phase was washed successively with 0.25 M NaHCO3 aq. water and brine
4. dry with materialdried (Na2SO4)
5. customevaporated to dryness
6. customto give crude product (19.8 g) as a yellow oil, which
7. customPurification of 8 g of this material by column chromatography (three times, SiO2
8. washfirst eluting with 1:9 EtOAc