Tin tetrachloride → trans-1-(5-Ethyl-2-furanyl)-1,2,3,4-tetrahydro-6,7-methylenedioxy-naphthalene-2-carboxylic acid

Temperatur

0 °C

To a freshly prepared solution of LDA (15 mmol) in 30 mL of THF cooled to -78° C. was added a solution of 3,4-methylenedioxybenzenebutanoic acid, methyl ester (14 mmol), from step 558 above, in 10 mL of THF. The solution was stirred for 5 minutes, and a solution of 5-ethylfuran-2-carboxaldehyde (13.8 mmol), from step 55b above, in 30 mL of THF was added. The reaction mixture was warmed to 0° C., and the reaction was quenched with 10 mL of satd NH4Cl. The organic layer was separated, and the aqueous layer was extracted with ether. The organic layers were combined, dried and concentrated. The residue was dissolved in 50 mL of methylene chloride, and the solution was cooled to 0° C. To this solution was added a solution of SnCl4 (1M, 13 mmol) in methylene chloride, and the reaction mixtrue was stirred for 5 minutes. The reaction was quenched with 1 N HCl (10 mL). The organic layer was separated, and the aqueous layer was extracted with methylene chloride. The organic layers were combined, dried, filtered and concentrated. The crude methyl ester intermediate was hydrolyzed with KOH in methanol by standard procedures, and the title product was isolated (3.04 g). NMR (CDCl3) δ:6.56 (s, 1H), 6.54 (s, 1H), 5.91-5.81 (m, 4H), 4.39 (d, J=7 Hz, 1H), 3.13 (m, 1H), 2.80 (t, J=7 Hz, 2H), 2.59 (q, J=8 Hz, 2H), 2.18-1.96 (m, 2H), 1.20 (t, J=8 Hz, 3H).

1. customthe reaction was quenched with 10 mL of satd NH4Cl
2. customThe organic layer was separated
3. extractionthe aqueous layer was extracted with ether
4. customdried
5. concentrationconcentrated
6. dissolutionThe residue was dissolved in 50 mL of methylene chloride
7. temperaturethe solution was cooled to 0° C
8. customthe reaction
9. stirringmixtrue was stirred for 5 minutes
10. customThe reaction was quenched with 1 N HCl (10 mL)
11. customThe organic layer was separated
12. extractionthe aqueous layer was extracted with methylene chloride
13. customdried
14. filtrationfiltered
15. concentrationconcentrated

ORD-Eintrag

ord-b68080b2a17c4815bce8181f3b0ccc79

Quelldatensatz

uspto-grants-1997_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05597832