Reaction #2045002

Reaction equation

Capsaicin

K2CO3

sodium iodide

disodium phosphate

methyl 6-bromohexanoate

→

12

Yield 52.8%

6-{2-Methoxy-4-[(8-methyl-non-6-enoylamino)-methyl]-phenoxy}-hexanoic acid methyl ester

Yield 52.8%

Solvents

acetone

Conditions

Workup

1. 1
   Temperaturerefluxed for 24 hours
2. 2
   workup.DISTILLATIONAcetone was distilled off
3. 3
   workup.ADDITIONwater (15 ml) was added
4. 4
   FiltrationCrude 12 was filtered
5. 5
   Otherdried
6. 6
   Otherpurified by column chromatography on silica gel

Procedure

To a mixture of Capsaicin (2 g, 6.56 mmol), anhydrous K2CO3 (3 g, 22 mmol), sodium iodide (2 g, 13.3 mmol) and disodium phosphate (2 g, 14.2 mmol) in anhydrous acetone (50 ml) was added methyl 6-bromohexanoate (2 g, 9.6 mmol) and refluxed for 24 hours. Acetone was distilled off and water (15 ml) was added. Crude 12 was filtered, dried and purified by column chromatography on silica gel using benzene:ethyl acetate (9:1) to give pure 12 (1.5 g, 52.8%) as a pale white powder. The melting point was found to be 69.2-70.8° C.

Source