Azobenzene → 2-(2-hydroxy-5-methylphenyl)benztriazole N-oxide

HRID 257659

Reaction equation

HRID 257659 reaction equation
[OH-].[Na+].[N+:3]([C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][C:7]=1[N:12]=[N:13][C:14]1[CH:19]=[C:18]([CH3:20])[CH:17]=[CH:16][C:15]=1[OH:21])([O-])=[O:4].C1C2C(=O)C3C(=CC=CC=3)C=2C=CC=1.O=C[C@@H]([C@H]([C@@H]([C@@H](CO)O)O)O)O.N(C1C=CC=CC=1)=NC1C=CC=CC=1>O.CO>[OH:21][C:15]1[CH:16]=[CH:17][C:18]([CH3:20])=[CH:19][C:14]=1[N:13]1[N+:3]([O-:4])=[C:6]2[CH:11]=[CH:10][CH:9]=[CH:8][C:7]2=[N:12]1

Participants

8

Reactant 5

HCID 2272AzobenzeneHCID 10241FluorenoneHCID 14798Sodium HydroxideHCID 740294-Methyl-2-[2-(2-nitrophenyl)diazenyl]phenolHCID 107526(2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanal

Product 1

HCID 132146462-(2-hydroxy-5-methylphenyl)benztriazole N-oxide

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

Example 9 of U.S. Pat. No. 4,835,284 is duplicated. A mixture of methanol (60 ml), water (30 ml), 97% sodium hydroxide (12.4 g), and 2-nitro-2'-hydroxy-5'-methyl azobenzene (12.9 g) is heated and stirred at 45°-50° C. 9-Fluorenone (1.0 g) and then glucose (5.5 g) are added to the resultant mixture over 30 minutes while stirring. The mixture is further stirred at 75° C. (boiling point) for 7 hours. As a result, the azobenzene disappears to produce 2-(2'-hydroxy-5'-methylphenyl)benzotriazole-N-oxide. Glucose (6 g) is then added to the reaction liquor over 30 minutes and the reaction is conducted 75° C. (boiling point) for further 6 hours. As a result, the above prepared N-oxide disappears. Thereafter, water (50 ml) is added to the reaction liquor, and the resultant reaction liquor is neutralized with 62% sulfuric acid (15 g) to precipitate a crystal. The precipitated crystal is separated by filtration, and the separated crystal is fully washed with water and further with methanol. The washed crystal is then dried, thus obtaining 9.6 g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole having a melting point of 128° to 130° C. at the yield of 85.0%. One can see that the reaction using the aromatic ketone 9-fluorenone takes over 14 hours to complete.

Workup

  1. temperatureis heated
  2. stirringwhile stirring
  3. stirringThe mixture is further stirred at 75° C. (boiling point) for 7 hours

Sources & evidence

ORD record
ord-62644564fd1341a587c20dcdf737a2b5
Source dataset
uspto-grants-1993_11
Patent number
US05262541

Linked notes

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