Diethyl Ether → 4H-Furo[3,2-c][l]benzopyran-2,3-dione

HRID 1649854Notes

Reaction equation

C[Si](C)(C)[O:3][C:4]1[C:9]2[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=2[O:7][CH2:6][CH:5]=1.CC[O:18][CH2:19][CH3:20].C([O:24]C(C)C)(C)C>>[O:3]1[C:4]2[C:9]3[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=3[O:7][CH2:6][C:5]=2[C:19](=[O:18])[C:20]1=[O:24]

Participants

Reactant 3

HCID 3283Diethyl Ether

HCID 7914Diisopropyl Ether

HCID 11379020Silane, (2H-1-benzopyran-4-yloxy)trimethyl-

Product 1

HCID 142560214H-Furo[3,2-c][l]benzopyran-2,3-dioneYield 86%

Procedure

To a stirred solution of 4-[(trimethylsilyl)oxy]-2H-1-benzopyran (L. H. Hellberg, and A. Zuarez, Tetrahedron Letters, 40, 3553 (1974)) (205.8 g, 0.917 mole) in anhydrous ether (600 ml) oxalyl chloride (58.2 g, 0.458 mole) is added dropwise over a period of 40 minutes at room temperature under nitrogen. The suspension is stirred at room temperature for 18 hours and then diluted with isopropyl ether (~300 ml). The precipitate is collected by filtration and washed with isopropyl ether to give 80.2 g (86%) of orange-red solid, mp 146°-8° C. Recrystallization from tetrahydrofuranisopropyl ether gives an analytical sample, mp 146°-148° C.

Workup

filtrationThe precipitate is collected by filtration
washwashed with isopropyl ether

Sources & evidence

ORD record: ord-14eb2b8c4ede4f0db1c9915645588a8d
Source dataset: uspto-grants-1990_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04921871

Reaction notes

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