反应详情

A solution of 170 mg (0.74 mmol) of metallic sodium in 150 mL of MeOH, 1.78 g (3.5 mmol) of the quaternary salt 22, 581 mg (3.5 mmol) of p-nitrosodimethylaniline, and 75 mL of dry CHCl3 was stirred for 5 hours at room temperature in an atmosphere of N2. The suspension was evaporated to dryness and the dried residue was dissolved in 100 mL of dry THF. To the resulting solution there was added 300 mg of LAH. After the mixture was stirred for 1 hour at room temperature, 600 mg of LAH was added. After 20 min the reaction was judged to be complete (TLC). The mixture was worked up in the usual way, and the solid that was collected was washed thoroughly with five portions of hot CH2Cl2 -MeOH (1:1). The aqueous filtrate was extracted with 3×200 mL portions of CH2Cl2. The combined organic layers were concentrated to dryness, and the residue was suspended in 30 mL of CH2Cl2 and 5 mL of MeOH. The suspension was flash chromatographed on silica gel, first with EtOAc as the eluant and then with EtOAc-MeOH (5:1). The purest fractions were combined, concentrated to a small volume, and cooled, whereupon the desired carbinol crystallized to give 518 mg (56% for the two steps) of 25, which melted at 257°-258° C. dec after one crystallization from EtOAc-MeOH (5:1): NMR (Me2SO-d6) δ11.46 (s, 1 H), 9.71 (s, 1 H), 8.43 (d, 1 H), 8.39 (d 1 H), 8.08 (d, 1 H), 7.62-7.48 (m, 2 H), 7.30-7.22 (m, 1 H), 5.25 (s, 3 H), 3:32 (s, 3 H).

1. customThe suspension was evaporated to dryness
2. dissolutionthe dried residue was dissolved in 100 mL of dry THF
3. additionTo the resulting solution there was added 300 mg of LAH
4. addition600 mg of LAH was added
5. waitAfter 20 min the reaction was judged
6. customthe solid that was collected
7. washwas washed thoroughly with five portions of hot CH2Cl2 -MeOH (1:1)
8. extractionThe aqueous filtrate was extracted with 3×200 mL portions of CH2Cl2
9. concentrationThe combined organic layers were concentrated to dryness
10. customchromatographed on silica gel, first with EtOAc as the eluant
11. concentrationconcentrated to a small volume
12. temperaturecooled, whereupon the desired carbinol
13. customcrystallized