HCID 21270152, compound → HCID 21270182, compound

7-Hydroxy-8-methyl-3-(4-nitrophenyl)-4H-1-benzopyran-4-one (440 mg), dissolved in a mixture of dioxane/ethanol 1:1 (200 ml), is hydrogenated for 15 h at room temperatutre over Raney nickel (200 mg). After filtration of the catalyst, the filtrate is evaporated under reduced pressure. The residue is dissolved in ethanol (75 ml) and hydrogenated for 15 h at room temperature over palladium 10% on active charcoal (200 mg) in the presence of p-toluenesulfonic acid monohydrate (760 mg). After filtration of the catalyst, the filtrate is evaporated under reduced pressure. The residue is dissolved in water (100 ml). The solution is neutralized to pH 7.5 by addition of a saturated solution of NaHCO3 and extracted with ethyl acetate (3×50 ml). The combined organic solutions are washed with water (2×20 ml), dried over MgSO4 and evaporated. The residue is purified by column chromatography on silica gel using dichloromethane/ethyl acetate 1:1 as eluent. The product is dried in vacuo to constant weight to yield 3,4-dihydro-7-hydroxy-8-methyl-3-(4-aminophenyl)-2H-1-benzopyran, m.p. 150°-151°.

1. filtrationAfter filtration of the catalyst
2. customthe filtrate is evaporated under reduced pressure
3. dissolutionThe residue is dissolved in ethanol (75 ml) and hydrogenated for 15 h at room temperature over palladium 10% on active charcoal (200 mg) in the presence of p-toluenesulfonic acid monohydrate (760 mg)
4. filtrationAfter filtration of the catalyst
5. customthe filtrate is evaporated under reduced pressure
6. dissolutionThe residue is dissolved in water (100 ml)
7. additionThe solution is neutralized to pH 7.5 by addition of a saturated solution of NaHCO3
8. extractionextracted with ethyl acetate (3×50 ml)
9. washThe combined organic solutions are washed with water (2×20 ml)
10. dry with materialdried over MgSO4
11. customevaporated
12. customThe residue is purified by column chromatography on silica gel
13. customThe product is dried in vacuo to constant weight

ORD record

ord-7fcb996b715c4e1bb2e0866f0d348320

Source dataset

uspto-grants-1989_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04814346