Ethylene Glycol → Diethyl 2,3-dihydrothieno[3,4-b][1,4]dioxine-5,7-dicarboxylate

HRID 1582410Notes

Reaction equation

[CH2:1]([O:3][C:4]([C:6]1[S:7][C:8]([C:13]([O:15][CH2:16][CH3:17])=[O:14])=[C:9]([OH:12])[C:10]=1[OH:11])=[O:5])[CH3:2].[CH2:18](O)[CH2:19]O>O1CCCC1>[CH2:16]([O:15][C:13]([C:8]1[S:7][C:6]([C:4]([O:3][CH2:1][CH3:2])=[O:5])=[C:10]2[C:9]=1[O:12][CH2:19][CH2:18][O:11]2)=[O:14])[CH3:17]

Participants

Conditions

Temperature: 25 °C

Procedure

ADC01 (2.9 g, 16.9 mmol) was slowly added to a solution of 3,4-dihydroxythiophene-2,5-dicarboxylic acid diethyl ester (2.0 g, 7.7 mmol), ethylene glycol (0.5 g, 8.5 mmol), and PHOL (3.4 g, 16.9 mmol) in dry tetrahydrofuran (150 ml) at 25° C. The reaction mixture was stirred for 3 h and then refluxed for 9 h. The reaction mixture was allowed to cool to 25° C. and concentrated by rotary evaporator to remove the THF. The residue was diluted with diethyl ether and allowed to stand overnight to enable the tributylphosphine oxide to precipitate out. The tributylphosphine oxide was then removed by filtration and the residue purified by chromatography on silica gel (eluant: ethyl acetate/ hexane=2/1) to give 2.1 g of 2,3-dihydro-thieno[3,4-b][1,4]dioxine-5,7-dicarboxylic acid diethyl ester as white crystals (95% yield) as fully characterized by 1H NMR, 13C NMR, HRMS, and elemental analysis.

Workup

temperaturerefluxed for 9 h
concentrationconcentrated by rotary evaporator
customto remove the THF
additionThe residue was diluted with diethyl ether
waitto stand overnight
customto precipitate out
customThe tributylphosphine oxide was then removed by filtration
customthe residue purified by chromatography on silica gel (eluant: ethyl acetate/ hexane=2/1)

Sources & evidence

ORD record: ord-893932b2e0e04472ae811988e4540847
Source dataset: uspto-grants-2004_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06734312B2

Reaction notes

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