Potassium Carbonate → Caleprunin B

HRID 1501524Notes

Reaction equation

HRID 1501524 reaction equation
[OH:1][C:2]1[CH:9]=[C:8]([O:10][CH3:11])[C:7]([O:12][CH3:13])=[CH:6][C:3]=1[CH:4]=O.C([O-])([O-])=O.[K+].[K+].Br[CH2:21][C:22](=[O:24])[CH3:23]>CC(=O)CC>[CH3:13][O:12][C:7]1[C:8]([O:10][CH3:11])=[CH:9][C:2]2[O:1][C:21]([C:22](=[O:24])[CH3:23])=[CH:4][C:3]=2[CH:6]=1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 11715BromoacetoneHCID 109869082-Hydroxy-4,5-dimethoxybenzaldehyde

Product 1

HCID 176913Caleprunin BYield 69.9%

Reagents, catalysts & solvents 1

HCID 6569Methyl Ethyl KetoneSolvent2×

Conditions

Temperature
0 °C

Procedure

To a solution of 2-hydroxy 4,5-dimethoxybenzaldehyde (2 g, 10.98 mmol) in butane-2-one (15 ml) added K2CO3 (6.07 g, 43.95 mmol) and then stirred at 0° C. for 10 min added bromoacetone (2.24 g, 16.47 mmol) and refluxed at 90° C. for 4 hr. After completion of the reaction butane-2-one was distilled off and water was added and extracted by ethylacetate twice. The EtOAc phase was dried over Na2SO4, Chromatography of the residue on silica gel (3:7 EtOAc/hexane) afforded the ketone A2 (1.69 g) in 70% yield pale yellow solid: 1H NMR (500 MHz, CDCl3) δ 7.29 (s, 1H), 7.04 (s, 1H), 6.98 (s, 1H), 3.94 (s, 3H), 3.90 (s, 3H), 2.30 (s, 3H) ppm. Mass: ESI [M+Na]+: 243.07; Elemental anal. calcd. for C12H12O4; C, 65.45; H, 5.49. found C, 65.20; H, 5.25.

Workup

  1. temperaturerefluxed at 90° C. for 4 hr
  2. distillationwas distilled off
  3. additionwater was added
  4. extractionextracted by ethylacetate twice
  5. dry with materialThe EtOAc phase was dried over Na2SO4, Chromatography of the residue on silica gel (3:7 EtOAc/hexane)

Sources & evidence

ORD record
ord-caeeae25586f4700be1728ac6a06b20e
Source dataset
uspto-grants-2015_12
Patent number
US09206201B2

Reaction notes

Loading…