Ethanol → 6-chloro-3,4-dihydro-2,4-dimethyl-2H-1,4-benzoxazine-8-carboxylic acid

HRID 329713Notes

Reaction equation

HRID 329713 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C:15]([O:17]C)=[O:16])[C:5]2[O:10][CH:9]([CH3:11])[C:8](=O)[N:7]([CH3:13])[C:6]=2[CH:14]=1.C(O)C.[OH-].[K+]>O>[Cl:1][C:2]1[CH:3]=[C:4]([C:15]([OH:17])=[O:16])[C:5]2[O:10][CH:9]([CH3:11])[CH2:8][N:7]([CH3:13])[C:6]=2[CH:14]=1

Participants

5

Reactant 3

HCID 702EthanolHCID 14797Potassium HydroxideHCID 14517233methyl 6-chloro-3,4-dihydro-2,4-dimethyl-3-oxo-2H-1,4-benzoxazine-8-carboxylate

Product 1

HCID 107526406-chloro-3,4-dihydro-2,4-dimethyl-2H-1,4-benzoxazine-8-carboxylic acidYield 93.6%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture of 5.1 g of methyl 6-chloro-3,4-dihydro-2,4-dimethyl-3-oxo-2H-1,4-benzoxazine-8-carboxylate, 20 ml of ethanol and 50 ml of 4% aqueous potassium hydroxide solution is refluxed with heating for 5 hours. The resultant solution is cooled and 350 ml of water is added thereto followed by filtration. The filtrate is made acid with concentrated hydrochloric acid. The precipitated crystals are collected by filtration, washed with water and dried, and then recrystallized from ethanol to give 4.28 g of 6-chloro-3,4-dihydro-2,4-dimethyl-2H-1,4-benzoxazine-8-carboxylic acid, melting at 191°14 193° C.

Workup

  1. temperatureis refluxed
  2. temperaturewith heating for 5 hours
  3. filtrationthereto followed by filtration
  4. filtrationThe precipitated crystals are collected by filtration
  5. washwashed with water
  6. customdried
  7. customrecrystallized from ethanol

Sources & evidence

ORD record
ord-26bed33914c849c49063600243f91019
Source dataset
uspto-grants-1990_01
Patent number
US04892872

Reaction notes

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