Phosphoric Acid → 2,3,6,7-Tetramethoxyfluorenone

HRID 1586292Notes

Reaction equation

O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.P(=O)(O)(O)[OH:16].[CH3:20][O:21][C:22]1[CH:23]=[C:24]([C:30]2[CH:38]=[C:37]([O:39][CH3:40])[C:36]([O:41][CH3:42])=[CH:35][C:31]=2[C:32](O)=O)[CH:25]=[CH:26][C:27]=1[O:28][CH3:29]>O>[CH3:29][O:28][C:27]1[C:26](=[O:16])[C:25]2[C:24](=[CH:23][C:22]=1[O:21][CH3:20])[C:30]1[C:31](=[CH:35][C:36]([O:41][CH3:42])=[C:37]([O:39][CH3:40])[CH:38]=1)[CH:32]=2

Participants

Conditions

Temperature: 100 °C

Procedure

Polyphosphoric acid which had been newly prepared from diphosphorus pentaoxide (50 g) and phosphoric acid (50 ml) was heated at 100° C. With stirring, 2-(3,4-dimethoxyphenyl)-4,5-dimethoxybenzoic acid (7.5 g) was added thereto as it is (in the crystal form) in several portions. After stirring at 100 to 120° C. for 2 hours, the reaction solution was poured into water (1.5 liter) and extracted with chloroform. The extract was washed with 2% aqueous sodium hydroxide solution, water and a saturated saline solution, then dried over sodium sulfate. The solvent was distilled off, and the residue was purified by silica gel column chromatography (eluent: chloroform) and recrystallized from ethyl acetate-n-hexane to give 5.0 g of 2,3,6,7-tetramethoxyfluorenone as an orange needle-like crystal.

Workup

stirringAfter stirring at 100 to 120° C. for 2 hours
extractionextracted with chloroform
washThe extract was washed with 2% aqueous sodium hydroxide solution, water
dry with materiala saturated saline solution, then dried over sodium sulfate
distillationThe solvent was distilled off
customthe residue was purified by silica gel column chromatography (eluent: chloroform)
customrecrystallized from ethyl acetate-n-hexane

Sources & evidence

ORD record: ord-dc981cb2ebcb44609214b1c8e3d97945
Source dataset: uspto-grants-1999_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05942641

Reaction notes

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