反应详情

33 g. of the ethyl ester of 2-(2-thianthrenyl)-2-hydroxypropionic acid (obtainable by reacting thianthrene with ethoxalyl chloride in 1,2-dichloroethane in the presence of AlCl3 at 10°-20° and reacting the thus-obtained ethyl ester of 2-thianthrenylglyoxylic acid (m.p. 68°-69°) with CH3MgI in ether) is dissolved in 500 ml. of xylene; 1 g. of p-toluenesulfonic acid is added thereto, and the mixture is refluxed for 31/2 hours with the use of a water trap. After cooling, the reaction mixture is washed with sodium bicarbonate solution and water, separated, dried over sodium sulfate, and evaporated. The thus-produced oily ethyl ester of 2-(2-thianthrenyl)-acrylic acid is dissolved in 270 ml. of ethanol and hydrogenated on 8 g. of 4% palladium charcoal at 50° and under 6 atmospheres until the hydrogen absorption is terminated (3 hours). The product is filtered, concentrated by evaporation, and the ethyl ester of 2-(2-thianthrenyl)-propionic acid is thus obtained, b.p. 225°-229°/0.2 mm.

1. customat 10°-20°
2. dissolutionis dissolved in 500 ml
3. temperaturethe mixture is refluxed for 31/2 hours with the use of a water trap
4. temperatureAfter cooling
5. washthe reaction mixture is washed with sodium bicarbonate solution and water
6. customseparated
7. dry with materialdried over sodium sulfate
8. customevaporated
9. dissolutionThe thus-produced oily ethyl ester of 2-(2-thianthrenyl)-acrylic acid is dissolved in 270 ml
10. customof 4% palladium charcoal at 50° and under 6 atmospheres until the hydrogen absorption
11. customis terminated (3 hours)
12. filtrationThe product is filtered
13. concentrationconcentrated by evaporation