Sulfuric Acid → Drometrizole

HRID 257656

Reaktionsgleichung

Reaktionsgleichung von HRID 257656
[OH-].[Na+].O=C[C@@H]([C@H]([C@@H]([C@@H](CO)O)O)O)O.[OH:15][C:16]1[CH:21]=[CH:20][C:19]([CH3:22])=[CH:18][C:17]=1[N:23]1[N+:27]([O-])=[C:26]2[CH:29]=[CH:30][CH:31]=[CH:32][C:25]2=[N:24]1.S(=O)(=O)(O)O>C1C2C(=O)C3C(=CC=CC=3)C=2C=CC=1.O.CO>[OH:15][C:16]1[CH:21]=[CH:20][C:19]([CH3:22])=[CH:18][C:17]=1[N:23]1[N:27]=[C:26]2[CH:29]=[CH:30][CH:31]=[CH:32][C:25]2=[N:24]1

Komponenten

8

Edukt 4

HCID 1118Sulfuric AcidHCID 14798Sodium HydroxideHCID 107526(2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanalHCID 132146462-(2-hydroxy-5-methylphenyl)benztriazole N-oxide

Produkt 1

HCID 17113DrometrizoleAusbeute 92,8 %

Reagenzien, Katalysatoren, Lösungsmittel 3

HCID 10241FluorenoneKatalysatorHCID 887MethanolLösungsmittelHCID 962WaterLösungsmittel

Versuchsvorschrift

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.

Aufarbeitung

  1. additionis further added to the mixture over one hour
  2. customThe mixture is reacted
  3. stirringwhile stirring at 75° C. (boiling point) for 5 hours
  4. customto precipitate a crystal
  5. customThe precipitated crystal is separated by filtration
  6. washthe separated crystal is fully washed with water and further with methanol
  7. customThe washed crystal is then dried

Quellen und Nachweise

ORD-Eintrag
ord-fcda0faead224a2096c76369bb9b90e0
Quelldatensatz
uspto-grants-1993_11
Patentnummer
US05262541

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