反应详情

270 μl of 2-(methyldithio)isobutyraldehyde and 730 μl of titanium isopropoxide are added to a suspension of 390 mg of 4-[2-aminoethoxy]-2,6-bis(hydroxymethyl)pyridine (prepared after deprotection of the Boc group from 4-(2-(tert-butoxycarbonylamino)ethoxy)-2,6-bis(hydroxymethyl)pyridine described on page 101 of WO 07085930) in 2 ml of THF. After 20 min, an additional 270 μl of 2-(methyldithio)isobutyraldehyde and an additional 730 μl of titanium isopropoxide are added and the mixture is stirred at AT for 2 h. 6 ml of ethanol are then added to the mixture, the mixture is stirred at AT for 20 min and then 124 mg of sodium cyanoborohydride are added to the mixture. After stirring for 45 min, an additional 124 mg of sodium cyanoborohydride are added and, after stirring for 1 h, the mixture is concentrated under RP and the residue is diluted in AcOEt and water. The resulting precipitate is filtered off and dissolved in a 1M aqueous HCl solution. The aqueous phase obtained is brought to basic pH with a 5M aqueous sodium hydroxide solution and extracted three times with DCM, and the combined organic phases are concentrated under RP. 322 mg of 4-[2-(2-methyl-2-(methyldisulphanyl)propylamino)ethoxy]-2,6-bis(hydroxymethyl)pyridine are thus obtained.

1. stirringthe mixture is stirred at AT for 20 min
2. stirringAfter stirring for 45 min
3. stirringafter stirring for 1 h
4. concentrationthe mixture is concentrated under RP
5. additionthe residue is diluted in AcOEt
6. filtrationThe resulting precipitate is filtered off
7. dissolutiondissolved in a 1M aqueous HCl solution
8. customThe aqueous phase obtained
9. extractionextracted three times with DCM
10. concentrationthe combined organic phases are concentrated under RP