1: coumarin With potassium hydroxide in water Reimer-Tiemann reaction; 8 h; Reflux; 2: chloroform in water Reimer-Tiemann reaction; pH=Ca. 12; 4 h; Reflux;
1: coumarin With potassium hydroxide in water Reimer-Tiemann reaction; 8 h; Reflux; 2: chloroform With 18-crown-6 ether in water Reimer-Tiemann reaction; pH=Ca. 12; 1.5 h; Reflux;