反応 #949658

反応方程式

benzene

p-toluenesulfonic acid

camphor sulfonic acid

compound 4

4-chromanol

→

compound 5

chromene

溶媒

xylene

toluene

chlorobenzene

反応条件

後処理

1. 1
   その他while removing liberated water
2. 2
   その他removing the activated hydroxy using a base such as triethylamine, N-methylmorpholine and diazabicycloundecene, particularly preferably diazabicycloundecene

実験手順

The compound 4 is refluxed under heating in a solvent such as benzene, chlorobenzene, toluene and xylene, in the presence of an acid catalyst such as p-toluenesulfonic acid and camphor sulfonic acid, using a Dean-Stark apparatus, while removing liberated water, or the hydroxyl group of compound 4 is activated into acetyl, trifluoroacetyl, methanesulfonyl, trifluoromethanesulfonyl or p-toluenesulfonyl using acetic anhydride, trifluoroacetic acid, methanesulfonyl chloride, trifluoromethanesulfonyl chloride or p-toluenesulfonyl chloride and removing the activated hydroxy using a base such as triethylamine, N-methylmorpholine and diazabicycloundecene, particularly preferably diazabicycloundecene, to give a chromene (compound 5 wherein R1, R2 and R3 are as defined above).

出典