Ammonia → 6-chloro-3,4-dihydro-2-methyl-3-oxo-2H-1,4-benzoxazine-8-carboxylic acid

HRID 329710

Reaction equation

HRID 329710 reaction equation
[C:1]([C:4]1[CH:15]=[C:14]([Cl:16])[CH:13]=[C:12]([N+:17]([O-])=O)[C:5]=1[O:6][CH:7]([CH3:11])[C:8](O)=[O:9])([OH:3])=[O:2].N>O>[Cl:16][C:14]1[CH:15]=[C:4]([C:1]([OH:3])=[O:2])[C:5]2[O:6][CH:7]([CH3:11])[C:8](=[O:9])[NH:17][C:12]=2[CH:13]=1

Participants

4

Reactant 2

HCID 222Ammonia2×HCID 145172302-(2-Carboxy-4-chloro-6-nitrophenoxy)propionic acid

Product 1

HCID 145172316-chloro-3,4-dihydro-2-methyl-3-oxo-2H-1,4-benzoxazine-8-carboxylic acidYield 92.2%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

To a solution of 960 g of ferrous sulfate heptahydrate in 2 1 of hot water is added a solution of 130 g of 2-(2-carboxy-4-chloro-6-nitrophenoxy)propionic acid and 200 ml of aqueous concentrated ammonia solution in 480 ml of water under stirring. After stirring for 30 minutes, to the reaction mixture is twice added 480 ml of aqueous concentrated ammonia solution. While the reaction mixture becomes exothermic, stirring is continued for an hour. The resultant mixture is filtered through a celite layer under reduced pressure and washed with 2 1 of hot water twice. The filtrate is cooled and made acid with concentrated hydrochloric acid. The precipitated crystals are washed with water and dried to give 100 g of 6-chloro-3,4-dihydro-2 -methyl-3-oxo-2H-1,4-benzoxazine-8-carboxylic acid, melting at 319°-320° C. with decomposition.

Workup

  1. stirringAfter stirring for 30 minutes, to the reaction mixture
  2. stirringstirring
  3. waitis continued for an hour
  4. filtrationThe resultant mixture is filtered through a celite layer under reduced pressure
  5. washwashed with 2 1 of hot water twice
  6. temperatureThe filtrate is cooled
  7. washThe precipitated crystals are washed with water
  8. customdried

Sources & evidence

ORD record
ord-d0cff010fc964bb5993de023b74ae6f4
Source dataset
uspto-grants-1990_01
Patent number
US04892872

Linked notes

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