Sulfuric Acid → t-Butyl 2-(6-amino-3-bromo-5-hydroxy-2-pyridylazo)-5-phenyl-3-thenoate

HRID 67719Notes

Reaction equation

HRID 67719 reaction equation
[NH2:1][C:2]1[S:6][C:5]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)=[CH:4][C:3]=1[C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14].S(=O)(=O)(O)O.[N:25]([O-])=O.[Na+].[NH2:29][C:30]1[C:35]([OH:36])=[CH:34][C:33]([Br:37])=[CH:32][N:31]=1>O.N1C=CC=CC=1>[NH2:29][C:30]1[N:31]=[C:32]([N:25]=[N:1][C:2]2[S:6][C:5]([C:7]3[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=3)=[CH:4][C:3]=2[C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])[C:33]([Br:37])=[CH:34][C:35]=1[OH:36]

Participants

7

Reactant 4

HCID 1118Sulfuric AcidHCID 116940412-Amino-5-bromo-3-hydroxypyridineHCID 20493231Tert-butyl 2-amino-5-phenylthiophene-3-carboxylateHCID 23668193Sodium Nitrite

Product 1

HCID 136186394t-Butyl 2-(6-amino-3-bromo-5-hydroxy-2-pyridylazo)-5-phenyl-3-thenoateYield 103.1%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 1049PyridineSolvent

Procedure

A solution of t-butyl 2-amino-5-phenyl-3-thenoate (8.26 g; 0.03 mole) in 2:5 acid (120 ml) (see Example 1) was chilled to -2° C. and concentrated sulfuric acid (5 ml) was added at such a rate that the temperature did not exceed 2° C.; a solution of sodium nitrite (2.16 g) in water (5 ml) was added dropwise below 2° C. The resulting diazonium solution was stirred at -2° C. to +2° C. for 45 minutes, then added in a slow stream with magnetic stirring to a cold (below 5° C.) solution of 2-amino-5-bromo-3-pyridinol (Example 2-L) (5.67 g; 0.03 mole) in pyridine (30 ml) and 2:5 acid (90 ml). The dye solution was stirred at 0° to 5° C. for 1.5 hours, then the cooling bath was removed and the mixture stirred for an additional 30 minutes. After drowning in cold water (2.5 liters), the dye was collected on a filter, washed with water and dried to yield 14.7 g of material with only traces of impurities.

Workup

  1. customdid not exceed 2° C.
  2. additionadded in a slow stream
  3. customthe cooling bath was removed
  4. stirringthe mixture stirred for an additional 30 minutes
  5. customthe dye was collected on a filter
  6. washwashed with water
  7. customdried

Sources & evidence

ORD record
ord-eb73ea4b293a4c70a2a530c37389b461
Source dataset
uspto-grants-1982_08
Patent number
US04346161

Reaction notes

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