Fuming sulfuric acid → 9-Chloro-6-fluoro-4-hydroxybenzo[g]isoquinoline-5,10-dione

HRID 234819Notes

Reaction equation

HRID 234819 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([F:19])=[C:6]([CH:18]=1)[CH2:7][C:8]1[C:13]([C:14]([OH:16])=O)=[CH:12][N:11]=[CH:10][C:9]=1[OH:17].[OH:20]S(O)(=O)=O.O=S(=O)=O.C(=O)(O)[O-].[Na+]>>[Cl:1][C:2]1[C:18]2[C:14](=[O:16])[C:13]3[CH:12]=[N:11][CH:10]=[C:9]([OH:17])[C:8]=3[C:7](=[O:20])[C:6]=2[C:5]([F:19])=[CH:4][CH:3]=1

Participants

4

Reactant 3

HCID 24681Fuming sulfuric acidHCID 516892Sodium BicarbonateHCID 106842494-(2'-Fluoro-5'-chlorobenzyl)-5-hydroxynicotinic acid

Product 1

HCID 153619399-Chloro-6-fluoro-4-hydroxybenzo[g]isoquinoline-5,10-dione

Procedure

A mixture of 4-(5'-chloro-2'-fluorobenzyl) -5-hydroxynicotinic acid of Preparative Example 27 (0.15 g) and 20% oleum (2 mL) is stirred for 45 minutes at 125°-130° C. (external bath temperature). The reaction mixture is then allowed to cool at room temperature and poured over 20 g of crushed ice and the resultant mixture neutralized with solid sodium bicarbonate to pH=7. The dione is extracted with dichloromethane (4×20 mL) and the combined organic phases are dried over MgSO4 and concentrated to dryness. The product is obtained as a yellow-tan solid (0.12 g) which darkens on standing in air.

Workup

  1. extractionThe dione is extracted with dichloromethane (4×20 mL)
  2. dry with materialthe combined organic phases are dried over MgSO4
  3. concentrationconcentrated to dryness

Sources & evidence

ORD record
ord-7142648fece649e6bb04bd2aecdec0f4
Source dataset
uspto-grants-1997_01
Patent number
US05596097

Reaction notes

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