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

HRID 257655

Reaction equation

HRID 257655 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].C1(C=CC(O)=CC=1)O.O=C[C@@H]([C@H]([C@@H]([C@@H](CO)O)O)O)O.N(C1C=CC=CC=1)=NC1C=CC=CC=1.S(=O)(=O)(O)O>C1(C)C=CC=CC=1.O>[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

9

Reactant 6

HCID 785HydroquinoneHCID 1118Sulfuric AcidHCID 2272AzobenzeneHCID 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-oxideYield 99.2%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 1140TolueneSolvent

Conditions

Temperature
60 °C

Procedure

Example 5 of U.S. Pat. No. 4,835,284 is duplicated. Water (70 ml), 97% sodium hydroxide 5.2 g, 2-nitro-2'-hydroxy-5'-methylazobenzene (12.9 g) and toluene (10 ml) are mixed and heated to 60° C. After stirring, hydroquinone (0.6 g) is added and glucose (5.0 g) is added to the mixture over one hour at 40° to 45° C. The mixture is further stirred for two hours, and the azobenzene disappears. The reaction liquor is neutralized with 62% sulfuric acid 5.8 g, and is cooled to 20° C. to precipitate a crystal. The crystal thus precipitated is separated by filtration to obtain a wet product 12 g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole-N-oxide (dry weight: 10.8 g, yield 90.0%, and melting point: 138° C. to 140° C.). To the wet product (12 g) thus obtained, are added methanol (60 ml), water (30 ml), 97% sodium hydroxide (13.0 g) and 9-fluorenone (0.5 g), and glucose (5.5 g) is further added to the mixture over one hour while stirring at 50° to 55° C. The mixture is reacted while stirring at 75° C. (boiling point) for 5 hours. As a result, the N-oxide disappears. The reaction liquor is neutralized with 62% sulfuric acid 19.8 g to pH 8 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 9.4 g of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole having a melting point of 128° to 130° C. at the yield of 92.8%. One can see that the reaction using an aromatic ketone takes over 9 hours to complete. Two catalysts are also required.

Workup

  1. stirringThe mixture is further stirred for two hours
  2. temperatureis cooled to 20° C.
  3. customto precipitate a crystal
  4. customThe crystal thus precipitated
  5. customis separated by filtration

Sources & evidence

ORD record
ord-c2a4fb87bd844acdb5f7ecbb785dd178
Source dataset
uspto-grants-1993_11
Patent number
US05262541

Linked notes

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