Reacción #216096

Ecuación de reacción

NaOH

β-lactose peracetate

ethanethiol

BF3 Et2O

→

Ethyl 4-O-β-galactopyranosyl-1-thio-β-D-glucopyranoside

Disolventes

toluene ethyl acetate

CH2Cl2

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrono more reaction
2. 2
   OtroThe organic layer was directly evaporated
3. 3
   workup.ADDITIONNaOMe in methanol (10 ml, 0.5M) was added
4. 4
   OtroThe TLC (ethyl acetate/acetic acid/methanol/water 12/3/3/3) yields an Rf 0.41
5. 5
   Filtraciónfiltered
6. 6
   Concentraciónconcentrated The residue
7. 7
   Otrowas recrystallized from ethanol (300 ml)

Procedimiento

To a mixture of β-lactose peracetate (50 g), ethanethiol (6.9 g, 822 ml) and 200 ml dry CH2Cl2 was added BF3 /Et2O (8.5 g, 7.3 ml) at RT. After 2 hours, TLC (toluene/ethyl acetate 2/3) showed no more reaction. The mixture was shaken with ca 500 ml 1M NaOH. The organic layer was directly evaporated and taken up in methanol (150 ml), then NaOMe in methanol (10 ml, 0.5M) was added and the mixture was stirred overnight at RT. The TLC (ethyl acetate/acetic acid/methanol/water 12/3/3/3) yields an Rf 0.41. The reaction mixture was neutralized with Dowex (50w×8, H+) filtered and concentrated The residue was recrystallized from ethanol (300 ml). Yield 16.4 g, 56%, mp 191°-192° C.

Fuente