Ethylene Glycol → 6-Bromo-5,8-dimethylspiro[thiochromane-4,2'-[1,3]dioxolane]
Reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([CH3:14])[C:5]2[S:10][CH2:9][CH2:8][C:7](=[O:11])[C:6]=2[C:12]=1[CH3:13].[CH2:15](O)[CH2:16][OH:17].C(OC)(OC)OC.O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C(OCC)C>[Br:1][C:2]1[CH:3]=[C:4]([CH3:14])[C:5]2[S:10][CH2:9][CH2:8][C:7]3([O:17][CH2:16][CH2:15][O:11]3)[C:6]=2[C:12]=1[CH3:13]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 1
Procedure
26.06 g (0.096 mol) of the title compound of Step C, 250 mL of ethylene glycol, 170 mL of trimethyl orthoformate (purchased from Aldrich Chemical Company), and 0.06 g of p-toluenesulfonic acid monohydrate were stirred together at 80° C. under nitrogen overnight. The mixture was diluted with 400 mL of diethyl ether. The resulting mixture was washed with a 1:1 mixture of 1N sodium hydroxide:saturated aqueous NaCl (2×600 mL) and then with saturated aqueous NaCl (1×600 mL). The organic layer was dried (Na2SO4), filtered, and evaporated to dryness. The crude product was chromatographed over silica gel eluting with a mixture of ethyl acetate:hexane (1:9) to yield 24.73 g of the title compound of Step D as a solid melting at 97° C. (dec). 1H NMR (CDCl3): δ2.2 (s,3H), 2.3 (m,2H), 2.4 (s,3H), 3.0 (m,2H), 4.15 (m,2H), 4.3 (m,2H), 7.3 (s,1H).
Workup
- washThe resulting mixture was washed with a 1:1 mixture of 1N sodium hydroxide
- dry with materialThe organic layer was dried (Na2SO4)
- filtrationfiltered
- customevaporated to dryness
- customThe crude product was chromatographed over silica gel eluting with a mixture of ethyl acetate:hexane (1:9)
Sources & evidence
- ORD record
- ord-59059e609428495a95a48f0b9dbf228c
- Source dataset
- uspto-grants-1999_09
- Patent number
- US05952266
Reaction notes
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