Reaktion #344321

Reaktionsgleichung

carboxybenzo-1,2,3-thiadiazole

triethyl borate

methanol

→

title compound

7-hydroxymethylbenzo-1,2,3-thiadiazole

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONthere are added dropwise under a nitrogen atmosphere
2. 2
   workup.STIRRINGThe mixture is stirred overnight
3. 3
   Sonstigeto stand at room temperature
4. 4
   Temperaturcooled down to 5°-10° C.
5. 5
   workup.STIRRINGwith stirring
6. 6
   SonstigeThe mixture is subsequently evaporated in vacuo
7. 7
   workup.ADDITIONa further 300 ml of methanol are added
8. 8
   Sonstigethe mixture is re-evaporated
9. 9
   SonstigeThe residue is purified on silica gel (solvent: ethyl acetate/hexane)
10. 10
    Sonstigethe product obtained
11. 11
    Sonstigeis recrystallised from ethyl acetate/hexane

Vorschrift

To a suspension of 54 g of carboxybenzo-1,2,3-thiadiazole in 420 ml of tetrahydrofuran there are added dropwise under a nitrogen atmosphere with stirring at room temperature 110 ml of triethyl borate, the mixture is stirred for a further hour and subsequently treated dropwise with 45.6 ml of boranedimethyl sulfide complex in 60 ml of tetrahydrofuran, with gentle cooling, during which process gas is evolved vigorously. The mixture is stirred overnight and allowed to stand at room temperature and then cooled down to 5°-10° C. and treated dropwise with 200 ml of methanol with stirring and vigorous cooling, during which process gas is again evolved vigorously. The mixture is subsequently evaporated in vacuo, a further 300 ml of methanol are added, and the mixture is re-evaporated. The residue is purified on silica gel (solvent: ethyl acetate/hexane), and the product obtained is recrystallised from ethyl acetate/hexane. The title compound obtained melts at 79°-81° C.

Quelle