反応 #87950

反応方程式

sodium hydroxide

methyl 7-methoxymethyl-2H-chromene-8-carboxylate

Intermediate 9

methyl 7-methoxymethyl-2H-chromene-8-carboxylate

bromoform

ethyl acetate

→

methyl cis-(1aRS,7bSR)-1,1-dibromo-5-methoxymethyl-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylate

溶媒

brine

反応条件

後処理

1. 1
   温度After cooling
2. 2
   抽出The aqueous layer was further extracted with ethyl acetate
3. 3
   乾燥the combined organic layers were dried (MgSO4)
4. 4
   ろ過filtered
5. 5
   その他The filtrate was evaporated to dryness
6. 6
   その他the residue was purified by chromatography on silica
7. 7
   洗浄eluting with a mixture of TBME and cyclohexane with a gradient of 0-35%

実験手順

Aqueous sodium hydroxide solution (50% w/v, 1.63 mL) was added slowly to a vigorously stirred mixture of methyl 7-methoxymethyl-2H-chromene-8-carboxylate (Intermediate 9, 0.875 g), benzyltriethylammonium chloride (0.173 g) and bromoform (15 mL). The resultant mixture was vigorously stirred and heated at 60° C. for 3 hours. After cooling, the mixture was poured into a mixture of brine and ethyl acetate. The aqueous layer was further extracted with ethyl acetate and the combined organic layers were dried (MgSO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of TBME and cyclohexane with a gradient of 0-35% to give methyl cis-(1aRS,7bSR)-1,1-dibromo-5-methoxymethyl-1,1a,2,7b-tetrahydrocyclopropa[c]chromene-4-carboxylate (1.06 g) as a white solid.

出典