Methanol → 1,3-Dioxane, 2-(4-chlorophenyl)-2-methyl-

To a stirred mixture of 4-chloroacetophenone (1.3 mL, 10 mmol), triethylformate (2.0 mL, 12 mmol), 1,3-propanediol (2.2 mL, 30 mmol) and dry methanol (1.2 mL) in dry CH2Cl2 (50 mL) was added NBS (53 mg, 0.30 mmol). The mixture was protected from light and stirred at room temperature under an inert atmosphere of nitrogen for 70 h. After the mixture was washed with saturated aqueous sodium bicarbonate solution (20 mL), the aqueous phase was extracted with dichloromethane (3×30 mL). The combined organic solution was washed with water (2×20 mL), brine (1×20 mL), then dried (Na2SO4) and concentrated under reduced pressure. Flash column chromatography of the residue, eluting with 37% aqueous ammonia:ether:hexane (0.02:1:6) afforded 2-(4-chlorophenyl)-2-methyl-1,3-dioxane (20) as a colourless oil (1.1 g, 52%). 1H nmr (200 MHz, CDCl3) 1.49 (s, 3H, CH3), 1.98-2.25 (m, 2H, OCH2CH2CH2O), 3.65-4.10 (m, 4H, OCH2CH2CH2O), 7.30-7.50 (m, 4H, 4×ArH).

1. washAfter the mixture was washed with saturated aqueous sodium bicarbonate solution (20 mL)
2. extractionthe aqueous phase was extracted with dichloromethane (3×30 mL)
3. washThe combined organic solution was washed with water (2×20 mL), brine (1×20 mL)
4. dry with materialdried (Na2SO4)
5. concentrationconcentrated under reduced pressure
6. washFlash column chromatography of the residue, eluting with 37% aqueous ammonia:ether:hexane (0.02:1:6)

ORD record

ord-54f1ec04175a45dc818c7e7e60e917bf

Source dataset

uspto-grants-2011_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07863313B2