Sulfuric Acid → (8S,9R)-2,3-Dimethyl-8-hydroxy-7-methylidene-9-phenyl-7,8,9,10-tetrahydroimidazo[1,2-h][1,7]-naphthyridine

HRID 895600Notes

Reaction equation

HRID 895600 reaction equation
[CH3:1][C:2]1[N:3]=[C:4]2[C:13]3[NH:12][C@H:11]([C:14]4[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=4)[C@@H:10]([OH:20])[C@:9]([CH3:22])(O)[C:8]=3[CH:7]=[CH:6][N:5]2[C:23]=1[CH3:24].S(=O)(=O)(O)O.C(=O)([O-])O.[Na+]>COCCO>[CH3:1][C:2]1[N:3]=[C:4]2[C:13]3[NH:12][C@H:11]([C:14]4[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=4)[C@@H:10]([OH:20])[C:9](=[CH2:22])[C:8]=3[CH:7]=[CH:6][N:5]2[C:23]=1[CH3:24]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 516892Sodium BicarbonateHCID 10286525(7R,8R,9R)-2,3,7-trimethyl-7,8-dihydroxy-9-phenyl-7,8,9,10-tetrahydroimidazo[1,2-h][1,7]naphthyridine

Product 1

HCID 20812188(8S,9R)-2,3-Dimethyl-8-hydroxy-7-methylidene-9-phenyl-7,8,9,10-tetrahydroimidazo[1,2-h][1,7]-naphthyridineYield 23.3%

Reagents, catalysts & solvents 1

HCID 80192-MethoxyethanolSolvent

Procedure

A mixture of 1.0 g of (7R,8R,9R)-2,3,7-trimethyl-7,8-dihydroxy-9-phenyl-7,8,9,10-tetrahydroimidazo[1,2-h][1,7]naphthyridine and 0.45 g of conc. sulfuric acid in 15 ml of 2-methoxyethanol is vigorously stirred at room temperature for 48 h, the reaction mixture is poured into 50 ml of saturated aqueous sodium hydrogencarbonate solution, extracted three times with 50 ml of dichloromethane each time, and the organic phases are combined and washed with a little water. After stripping off the solvent in vacuo, the oily residue obtained is purified on silica gel (eluent: dichloromethane/methanol 100/1). 0.22 g of the title compound is obtained as pale yellow crystals of melting point 199-202° C. (diethyl ether).

Workup

  1. extractionextracted three times with 50 ml of dichloromethane each time
  2. washwashed with a little water
  3. customthe oily residue obtained
  4. customis purified on silica gel (eluent: dichloromethane/methanol 100/1)

Sources & evidence

ORD record
ord-3d68ec10f05842718c163861bfcdb88f
Source dataset
uspto-grants-2005_07
Patent number
US06916825B2

Reaction notes

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