反応 #216096

反応方程式

NaOH

β-lactose peracetate

ethanethiol

BF3 Et2O

→

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

溶媒

toluene ethyl acetate

CH2Cl2

反応条件

後処理

1. 1
   その他no more reaction
2. 2
   その他The organic layer was directly evaporated
3. 3
   workup.ADDITIONNaOMe in methanol (10 ml, 0.5M) was added
4. 4
   その他The TLC (ethyl acetate/acetic acid/methanol/water 12/3/3/3) yields an Rf 0.41
5. 5
   ろ過filtered
6. 6
   濃縮concentrated The residue
7. 7
   その他was recrystallized from ethanol (300 ml)

実験手順

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.

出典