Phosphorus oxychloride → 4-Methoxy-7,8-dihydro-[1,3]dioxolo[4,5-g]isoquinoline

Temperature

100 °C

2.23 g (10 mmol) of N-[2-(3-methoxy-4,5-methylenedioxyphenyl)ethyl]formamide (C) was dissolved in 25.5 ml of methylene chloride, and to this mixture was added 1.87 ml (20 mmol) of phosphorus oxychloride. The resulting mixture was refluxed under heating for 7 hours and concentrated under reduced pressure. The residue was added with 50 ml of toluene and 50 ml of water, then further added with 14 ml of 20% sodium hydroxide aqueous solution, stirred under heating at 100° C. for one hour and cooled. The reaction mixture was separated and the aqueous layer was extracted with 25 ml of toluene. The toluene layers were combined, washed with 25 ml of water and dried over anhydrous magnesium sulfate. Distillation off the solvent gave 2.00 g of 8-methoxy-6,7-methylenedioxy-3,4-dihydroisoquinoline (D) (yield: 98%).

1. temperatureThe resulting mixture was refluxed
2. temperatureunder heating for 7 hours
3. concentrationconcentrated under reduced pressure
4. additionThe residue was added with 50 ml of toluene and 50 ml of water
5. additionfurther added with 14 ml of 20% sodium hydroxide aqueous solution
6. temperaturecooled
7. customThe reaction mixture was separated
8. extractionthe aqueous layer was extracted with 25 ml of toluene
9. washwashed with 25 ml of water
10. dry with materialdried over anhydrous magnesium sulfate
11. distillationDistillation off the solvent

ORD record

ord-0a22bb4bff4d4c09adc0ecdeeb0e6b1b

Source dataset

uspto-grants-1988_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04746747