Oxalyl chloride → 4H-[1]-Benzothiopyrano[4,3-b]furan-2,3-dione

HRID 34334Notes

Reaction equation

HRID 34334 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[S:7][CH2:6][CH:5]=1.[C:16](Cl)(=[O:20])[C:17](Cl)=[O:18]>CCOCC>[O:3]1[C:17](=[O:18])[C:16](=[O:20])[C:5]2[CH2:6][S:7][C:8]3[CH:13]=[CH:12][CH:11]=[CH:10][C:9]=3[C:4]1=2

Participants

4

Reactant 2

HCID 65578Oxalyl chlorideHCID 127939784-[trimethyl[silyl]oxy]-2H-benzothiopyran

Product 1

HCID 142558494H-[1]-Benzothiopyrano[4,3-b]furan-2,3-dioneYield 82.3%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent2×

Procedure

To a stirred mixture of 4-[trimethyl[silyl]oxy]-2H-benzothiopyran (380.5 g, 1.609 mol), prepared according to the method of L. Hellberg et al, Tet. Letters, 3553-3554 (1974), and one liter of diethyl ether, were added 103.8 g (0.818 mol) of oxalyl chloride in a dropwise manner over a period of 50 minutes at room temperature under nitrogen. The mixture was stirred at room temperature for 17 hours after which time the ether was removed under reduced pressure. The residue was triturated with isopropyl ether/hexane to give 146.9 g (82.3%) of a brown crystalline solid, mp 156° C. (dec).

Workup

  1. customprepared
  2. customwas removed under reduced pressure
  3. customThe residue was triturated with isopropyl ether/hexane

Sources & evidence

ORD record
ord-92c03c82a1e64f3caf538decb74211ff
Source dataset
uspto-grants-1988_08
Patent number
US04761424

Reaction notes

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