Hydrochloric Acid → 2,3-dihydrospiro[4H-1-benzothiopyran-4,2'-[1,3]dioxolane]-6-carboxylic acid 1,1-dioxide

HRID 617697Notes

Reaction equation

[O:1]1[CH2:5][CH2:4][O:3][C:2]21[C:10]1[CH:11]=[C:12]([C:15]([OH:17])=[O:16])[CH:13]=[CH:14][C:9]=1S[CH2:7][CH2:6]2.C([O-])(=O)C.[Na+].O[O:24][S:25]([O-:27])=O.[K+].S([O-])(O[O-])(=O)=O.[K+].[K+].Cl>O.CO>[O:1]1[CH2:5][CH2:4][O:3][C:2]21[C:10]1[CH:11]=[C:12]([C:15]([OH:17])=[O:16])[CH:13]=[CH:14][C:9]=1[S:25](=[O:27])(=[O:24])[CH2:7][CH2:6]2

Participants

Conditions

Temperature: 0 °C

Procedure

8.5 g (0.034 mol) of the title compound of Step D and 41.5 g (0.51 mol) of sodium acetate were added to 160 mL of methanol. The suspension was cooled to about 0° C., and a solution of 35.2 g (0.057 mol) of OXONE® (potassium peroxymonosulfate, purchased from Aldrich Chemical Company) in 160 mL of water was added dropwise while keeping the temperature below 6° C. The mixture was warmed to room temperature and stirred under nitrogen overnight. The mixture was diluted with 100 mL of water, cooled to about 0° C., acidified to pH 2 with concentrated hydrochloric acid, and extracted with chloroform (3×200 mL). The combined organic layers were dried (MgSO4), filtered, and evaporated to dryness. The crude product was triturated with a hexane:diethyl ether mixture (9:1) to yield 6.98 g of the title compound of Step E as a solid melting at 208° C. (dec). 1H NMR (Me2SO-d6): δ2.6 (m,2H), 3.7 (m,2H), 4.1-4.2 (m,4H), 7.9-8.15 (3H), 13.6 (br s,1H).

Workup

customthe temperature below 6° C
temperatureThe mixture was warmed to room temperature
temperaturecooled to about 0° C.
extractionextracted with chloroform (3×200 mL)
dry with materialThe combined organic layers were dried (MgSO4)
filtrationfiltered
customevaporated to dryness
customThe crude product was triturated with a hexane

Sources & evidence

ORD record: ord-ae6a22b4031c40f0b3df98793ceb13c7
Source dataset: uspto-grants-1999_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05952266

Reaction notes

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