反应详情

3-Methyl-4-nitrobenzyl bromide (60 g, 261 mmol) was added portionwise to a suspension of sodium 3-methoxy-3-oxopropane-1-sulfonate 13 (50 g, 1.1 equiv) in DMSO (400 ml) at r.t. (with occasional ice bath cooling to keep the temperature below 28 C) and this mixture was stirred at r.t. for 3 h (TLC (EtOAc/hexane 50%) indicated complete consumption of the starting material to cleanly form a new spot). MeOH (400 ml) was then added and the mixture was cooled down to −10 C. MeONa (62 ml of a 25% solution in MeOH) was added dropwise at −9 C and the reaction was warmed slowly to 0 C (where complete disappearance of the intermediate was seen by TLC). Finally, this mixture was poured portionwise into an aqueous solution containing hydroxylamine-O-sulfonic acid (118 g, 4 equiv) and NaOAc (107 g, 5 equiv) at 0 C (very exothermic reaction). The reaction was warmed very slowly to r.t. and was stirred at that temperature o.n. More water (1 L) and EtOAc (1 L) were added to dissolve the precipitate. The product was extracted into EtOAc, washed with brine and dried over Na2SO4. Evaporation of solvents gave a gummy solid, which was triturated in toluene (300 ml) for an hour to yield 49.35 g (82%) of pure 14 as a white solid.

1. temperaturecooling
2. customconsumption of the starting material to cleanly form a new spot)
3. additionMeOH (400 ml) was then added
4. temperaturethe mixture was cooled down to −10 C
5. additionMeONa (62 ml of a 25% solution in MeOH) was added dropwise at −9 C
6. temperaturethe reaction was warmed slowly to 0 C (where complete disappearance of the intermediate
7. additionFinally, this mixture was poured portionwise into an aqueous solution
8. customvery exothermic reaction)
9. dissolutionto dissolve the precipitate
10. extractionThe product was extracted into EtOAc
11. washwashed with brine
12. dry with materialdried over Na2SO4
13. customEvaporation of solvents
14. customgave a gummy solid, which
15. customwas triturated in toluene (300 ml) for an hour