Sulfuric Acid → Medorinone

HRID 1649168Notes

Reaction equation

HRID 1649168 reaction equation
[CH3:1][C:2]1[N:11]=[CH:10][CH:9]=[C:8]2[C:3]=1[CH:4]=[C:5](C#N)[C:6](=[O:12])[NH:7]2.S(=O)(=O)(O)O.[OH-].[NH4+]>O>[CH3:1][C:2]1[N:11]=[CH:10][CH:9]=[C:8]2[C:3]=1[CH:4]=[CH:5][C:6](=[O:12])[NH:7]2

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 14923Ammonium HydroxideHCID 57130685-methyl-2-oxo-1H-1,6-naphthyridine-3-carbonitrile

Product 1

HCID 5362132Medorinone

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

5-Methyl-1,6-naphthyridin-2(1H)-one also was prepared directly from the corresponding 3-cyano compound, as follows: A 650 g portion of 1,2-dihydro-5-methyl-2-oxo-1,6-naphthyridine-3-carbonitrile was added with stirring at room temperature to a solution of 2100 ml 18 M sulfuric acid in 350 ml of water. The reaction mixture was stirred mechanically and refluxed (internal temperature at 215°-220° C.) for 24 hours. The dark solution was allowed to come to ambient temperature and poured on ice. The solution was stirred and basified with 6 l of concentrated ammonium hydroxide to pH 10.5, the internal temperature being maintained at 20°-30° C. during this addition. The dark beige solid was collected by filtration, washed with a minimum of cold water and dried in an oven chamber at 65° overnight. The crude product was recrystallized twice from water with decolorizing charcoal treatment to produce 330 g of 5-methyl-1,6-naphthyridin-2(1H)-one, m.p. 245°-246° C.

Workup

  1. temperaturerefluxed (internal temperature at 215°-220° C.) for 24 hours
  2. customto come to ambient temperature
  3. additionpoured on ice
  4. stirringThe solution was stirred
  5. temperaturethe internal temperature being maintained at 20°-30° C. during this addition
  6. filtrationThe dark beige solid was collected by filtration
  7. washwashed with a minimum of cold water
  8. customdried in an oven chamber at 65° overnight
  9. customThe crude product was recrystallized twice from water with decolorizing charcoal treatment

Sources & evidence

ORD record
ord-f74b7fa137e649fe9d6c0270fbeef2a3
Source dataset
uspto-grants-1983_11
Patent number
US04415580

Reaction notes

Loading…