4-Methoxybenzenesulfonyl chloride → HCID 22997175, compound

2-(tetrahydro-3-furanyloxy)-1H-isoindole-1,3(2H)-dione (1.5 mmol, 357 mg) was combined with hydrazine (1.7 mmol, 0.053 mL) in anhydrous THF (3 mL) under nitrogen. The reaction immediately formed a white suspension and was allowed to stir at room temperature for 1 hour. The suspension was filtered directly into a flask containing 4-methoxybenzenesulfonyl chloride (1.5 mmol, 316 mg) and diisopropylethylamine (1.8 mmol, 0.320 mL) was added. After stirring at room temperature for 18 hours, the reaction was concentrated to a solid. The resulting solid was partitioned between ethyl acetate and 1N HCl, and the organic layer was separated and washed with a saturated aqueous solution of sodium bicarbonate and brine, and dried over magnesium sulfate. The crude product was concentrated to a white solid and purified by silica gel chromatography (1:1 hexanes/ethyl acetate). The purified product was then combined with ether and filtered to remove the residual phthalimide-hydrazine biproduct. The filtrate was then crystallized by adding hexanes providing 203 mg (48%) white crystals. Rf=0.2 (1:1 hexanes/ethyl acetate); H1-NMR (CDCl3): 67 7.82 (2H,d), 6.99 (2H,d), 6.85 (1H,s), 4.82-4.79 (1H,m), 3.97-3.87 (2H, m), 3.87 (3H,s), 3.83-3.70 (2H,m), 2.12-1.99 (2H,m).

1. customThe reaction
2. customimmediately formed a white suspension
3. filtrationThe suspension was filtered directly into a flask
4. additionwas added
5. stirringAfter stirring at room temperature for 18 hours
6. concentrationthe reaction was concentrated to a solid
7. customThe resulting solid was partitioned between ethyl acetate and 1N HCl
8. customthe organic layer was separated
9. washwashed with a saturated aqueous solution of sodium bicarbonate and brine
10. dry with materialdried over magnesium sulfate
11. concentrationThe crude product was concentrated to a white solid
12. custompurified by silica gel chromatography (1:1 hexanes/ethyl acetate)
13. filtrationfiltered
14. customto remove the residual phthalimide-hydrazine biproduct
15. customThe filtrate was then crystallized
16. additionby adding hexanes providing 203 mg (48%) white crystals

ORD record

ord-0bd842bfa20a45678832ef7b40ff66ab

Source dataset

uspto-grants-2003_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06613743B2