Phosphoric Acid → 3-Demethylcolchicine

HRID 1682247Notes

Reaction equation

HRID 1682247 reaction equation
[CH3:1][C:2]([NH:4][C@@H:5]1[C:21]2[C:14](=[CH:15][CH:16]=[C:17]([O:22][CH3:23])[C:18]([CH:20]=2)=[O:19])[C:13]2[C:8](=[CH:9][C:10]([O:28][C@@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@H]3O)=[C:11]([O:26][CH3:27])[C:12]=2[O:24][CH3:25])[CH2:7][CH2:6]1)=[O:3].OP(O)(O)=O.[OH-].[Na+]>O>[CH3:1][C:2]([NH:4][C@@H:5]1[C:21]2[C:14](=[CH:15][CH:16]=[C:17]([O:22][CH3:23])[C:18]([CH:20]=2)=[O:19])[C:13]2[C:8](=[CH:9][C:10]([OH:28])=[C:11]([O:26][CH3:27])[C:12]=2[O:24][CH3:25])[CH2:7][CH2:6]1)=[O:3]

Participants

5

Reactant 3

HCID 1004Phosphoric AcidHCID 14798Sodium HydroxideHCID 92763Colchicoside

Product 1

HCID 2996643-DemethylcolchicineYield 102.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
25 °C

Procedure

A mixture of 250 mg of colchicoside and 2 ml of 85-86% H3PO4 is stirred at 25° C. for 24 hours. The yellow solution is diluted with 10 ml of water, adjusted to pH 5 by addition of 2N NaOH and extracted with methylene chloride. The extracts are dried (Na2SO4), evaporated and chromatographed on Al2O3 (basic, Alfa Division, CH2C12 /MeOH=95:5). The appropriate fractions after evaporation of solvent and crystallization from acetone afford 180 mg (89%) of 3-demethylcolchicine: mp 176°-177° C. (resolidification at 205°-210° C. and 2nd mp 270° C. (dec.), [α]D =-151° (solvate crystal, CHCl3).

Workup

  1. extractionextracted with methylene chloride
  2. dry with materialThe extracts are dried (Na2SO4)
  3. customevaporated
  4. customchromatographed on Al2O3 (basic, Alfa Division, CH2C12 /MeOH=95:5)
  5. customThe appropriate fractions after evaporation of solvent and crystallization from acetone

Sources & evidence

ORD record
ord-ea6170817d5248558a3d751eeb199b7d
Source dataset
uspto-grants-1992_12
Patent number
US05175342

Reaction notes

Loading…