1,1-Ethanediol → 6-Bromo-5,8-dimethylspiro[thiochromane-4,2'-[1,3]dioxolane]

HRID 378810Notes

Reaction equation

[Br:1][C:2]1[C:3]([CH3:14])=[C:4]2[C:9](=[C:10]([CH3:12])[CH:11]=1)[S:8][CH2:7][CH2:6][C:5]2=[O:13].[CH:15](O)([OH:17])[CH3:16].O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C(OC)(OC)OC.C(OCC)C>[Br:1][C:2]1[C:3]([CH3:14])=[C:4]2[C:5]3([O:17][CH2:15][CH2:16][O:13]3)[CH2:6][CH2:7][S:8][C:9]2=[C:10]([CH3:12])[CH:11]=1

Participants

Conditions

Temperature: 80 °C

Procedure

58.4 g (0.22 mol) of 6-bromo-5,8-dimethyl-4-thiochromanone were dissolved in 380 ml of trimethyl orthoformate, admixed with 555 g (8.9 mol) of ethanediol and 0.2 g of p-toluenesulfonic acid monohydrate and stirred at 80° C. overnight. The mixture was subsequently allowed to cool, diluted with 500 ml of diethyl ether and washed with a 1:1 mixture of 1 M aqueous sodium hydroxide solution and sat. NaCl solution (2×500 ml) and subsequently with sat. NaCl solution (300 ml). The organic phase was dried over MgSO4 and concentrated using a rotary evaporator. The residue was taken up in 50 ml of heptaneldiethyl ether (9:1) and stored in a cold place. The crystals which had precipitated overnight were filtered off with suction, washed with cold heptane and dried.

Workup

temperatureto cool
washwashed with a 1:1 mixture of 1 M aqueous sodium hydroxide solution and sat. NaCl solution (2×500 ml) and subsequently with sat. NaCl solution (300 ml)
dry with materialThe organic phase was dried over MgSO4
concentrationconcentrated
customa rotary evaporator
customThe crystals which had precipitated overnight
filtrationwere filtered off with suction
washwashed with cold heptane
customdried

Sources & evidence

ORD record: ord-2d9e3ecf9bc24abbbd3d7d581b9c76a4
Source dataset: uspto-grants-2001_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06297196B1

Reaction notes

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