反应详情

To a stirred solution of 48 parts of ethyl 3,4-dihydro-6-(phenylmethoxy)-2H-1-benzopyran-2-carboxylate in 495 parts of methylbenzene were added dropwise 108 parts of a solution of [bis(2-methylpropyl)]aluminium hydride in methylbenzene at -80° C. Upon completion, stirring was continued for 30 minutes at -80° C. The reaction mixture was decomposed by the carefully addition of 24 parts of methanol. It was poured into 1000 parts of water and the whole was stirred for 15 minutes very carefully! The mixture was acidified with concentrate hydrochloric acid. After stirring for 5 minutes, the organic layer was separated, washed with water, dried, filtered and evaporated, yielding 39.8 parts (97%) of 3,4-dihydro-6-(phenylmethoxy)-2H-1-benzopyran-2-carboxaldehyde as a residue (intermediate 42).

1. stirringthe whole was stirred for 15 minutes very carefully
2. stirringAfter stirring for 5 minutes
3. customthe organic layer was separated
4. washwashed with water
5. customdried
6. filtrationfiltered
7. customevaporated