Glycerol → 2,3-Dihydro[1,4]dioxino[2,3-h]quinoline

Temperature

140 °C

A mixture of concentrated sulphuric acid (30 ml), boric acid (2.29 g; 47.20 mmol) iron (II) sulphate heptahydrate (1.09 g; 3.93 mmol) and 3-nitrobenzene sulphonic acid sodium salt (9.5 g; 42.36 mmol) was cooled to 0° C. before addition of glycerol (11 ml; 151.31 mmol) and 2,3-dihydro-1,4-benzodioxin-5-amine (4.6 g; 30.26 mmol) followed by water (30 ml). The mixture was then heated to 140° C. and stirred for 4 hours. The reaction was then cooled to rt before being poured onto ice water (150 ml) and filtered. The resulting mixture was then basified to pH 8 with 6N NaOH and stirred with EtOAc for 30 mins. The organics were separated and the aqueous layer extracted with EtOAc×3. The combined organic layers were filtered through kieselguhr, washed with brine and dried with MgSO4. The solvents were removed to afford the desired product (3.65 g; 65%).

1. temperatureThe reaction was then cooled to rt
2. additionbefore being poured onto ice water (150 ml)
3. filtrationfiltered
4. stirringstirred with EtOAc for 30 mins
5. customThe organics were separated
6. extractionthe aqueous layer extracted with EtOAc×3
7. filtrationThe combined organic layers were filtered through kieselguhr
8. washwashed with brine
9. dry with materialdried with MgSO4
10. customThe solvents were removed

ORD record

ord-94129f50e4fb4925a5cc92fe38c20e24

Source dataset

uspto-grants-2011_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08071592B2