P-Cresol → 4-Methylphenyl 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranoside

HRID 863779Notes

Reaction equation

[CH:1]1[C:6]([OH:7])=[CH:5][CH:4]=[C:3]([CH3:8])[CH:2]=1.C(O[CH:13]1[O:30][C@H:29]([CH2:31][O:32][C:33](=[O:35])[CH3:34])[C@H:24]([O:25][C:26](=[O:28])[CH3:27])[C@H:19]([O:20][C:21](=[O:23])[CH3:22])[C@H:14]1[O:15][C:16](=[O:18])[CH3:17])(=O)C>[Cl-].[Cl-].[Zn+2].C(Cl)Cl>[C:16]([O:15][C@@H:14]1[C@@H:19]([O:20][C:21](=[O:23])[CH3:22])[C@@H:24]([O:25][C:26](=[O:28])[CH3:27])[C@@H:29]([CH2:31][O:32][C:33](=[O:35])[CH3:34])[O:30][C@@H:13]1[O:7][C:6]1[CH:5]=[CH:4][C:3]([CH3:8])=[CH:2][CH:1]=1)(=[O:18])[CH3:17]

Participants

Conditions

Temperature: 160 °C

Procedure

8.9 g of p-cresol, 8.9 g of penta-O-acetyl-D-galactopyranose and 0.56 g of ZnCl2 are mixed, heated to 160° C. and kept at this temperature for 30 minutes, according to HELFERICH's method. After cooling to 60° C., the reaction medium is taken up with 400 ml of CH2Cl2 and washed with twice 400 ml of water and then with a solution of sodium hydroxide (≈1N) until the aqueous phase is practically colourless. The organic phase is finally washed with twice 400 ml of water, dried over anhydrous sodium sulfate and then evaporated to dryness in a water bath (temperature: 35°-40° C.) to give a residue of 7.08 g (yield=70%). Chromatography on a column of 60H silica (solvent: hexane/ethyl acetate: 90/10 v/v) gives 2.9 g of the compound 1 (yield=29%) and 1.17 g of its β anomer (yield=12%).

Workup

temperatureAfter cooling to 60° C.
washwashed with twice 400 ml of water
washThe organic phase is finally washed with twice 400 ml of water
dry with materialdried over anhydrous sodium sulfate
customevaporated to dryness in a water bath (temperature: 35°-40° C.)
customto give a residue of 7.08 g (yield=70%)

Sources & evidence

ORD record: ord-b559bc2bd68b4188b1d628d545dec434
Source dataset: uspto-grants-1996_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05561119

Reaction notes

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