Reaction #738761

Reaction equation

dihexylamine

triethylamine

(4-oxo-thiochroman-2-yl)-carboxylic acid

thionyl chloride

→

N,N-dihexyl-(4-oxo-thiochroman-2-yl)-carboxamide

Solvents

dichloromethane

dichloromethane

benzene

Conditions

Workup

1. 1
   Temperatureby reflux
2. 2
   Temperatureunder heating for 3 hours
3. 3
   ConcentrationThe reaction solution was concentrated under reduced pressure
4. 4
   Otherto give a residue
5. 5
   Temperaturecooling
6. 6
   workup.STIRRINGAfter stirring at room temperature overnight
7. 7
   Concentrationthe reaction solution was concentrated under reduced pressure
8. 8
   workup.ADDITIONto the residue was added ethyl acetate
9. 9
   Washthe mixture was washed with water, 1 N hydrochloric acid
10. 10
    Dryinga saturated aqueous sodium bicarbonate solution and a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate
11. 11
    OtherAfter removal of the drying agent
12. 12
    Filtrationby filtration
13. 13
    Concentrationthe filtrate was concentrated under reduced pressure
14. 14
    OtherThe residue was purified by chromatography (silica gel; Wakogel C200 (manufactured by Wako Pure Chemicals), developing solvent; hexane-ethyl acetate=5:1-3:1)
15. 15
    Otherrecrystallized from hexane

Procedure

To a solution of 20.00 g of (4-oxo-thiochroman-2-yl)-carboxylic acid in 200 ml of benzene was added 14.0 ml of thionyl chloride, followed by reflux under heating for 3 hours. The reaction solution was concentrated under reduced pressure to give a residue, a solution of which in 100 ml of dichloromethane was added dropwise to a solution of 24.6 ml of dihexylamine and 20.0 ml of triethylamine in 200 ml of dichloromethane under ice-cooling with stirring. After stirring at room temperature overnight, the reaction solution was concentrated under reduced pressure, and to the residue was added ethyl acetate, and the mixture was washed with water, 1 N hydrochloric acid, a saturated aqueous sodium bicarbonate solution and a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. After removal of the drying agent by filtration, the filtrate was concentrated under reduced pressure. The residue was purified by chromatography (silica gel; Wakogel C200 (manufactured by Wako Pure Chemicals), developing solvent; hexane-ethyl acetate=5:1-3:1) and recrystallized from hexane to give 29.22 g of N,N-dihexyl-(4-oxo-thiochroman-2-yl)-carboxamide.

Source