Hydrochloric Acid → 6-Chloro-2h-1,3-benzoxazine-2,4(3h)-dione

HRID 1611871Notes

Reaction equation

HRID 1611871 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([OH:11])=[C:6]([CH:10]=1)[C:7]([NH2:9])=[O:8].N1C=CC=CC=1.Cl[C:19](OCC)=[O:20].Cl>O.C(#N)C>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:11][C:19](=[O:20])[NH:9][C:7](=[O:8])[C:6]=2[CH:10]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 1049PyridineHCID 10928Ethyl chloroformateHCID 3480945-Chloro-2-hydroxybenzamide

Product 1

HCID 903596-Chloro-2h-1,3-benzoxazine-2,4(3h)-dioneYield 85.3%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6342AcetonitrileSolvent

Conditions

Temperature
95 °C

Procedure

A solution of 10 g of 5-chloro-2-hydroxybenzamide (58.0 mmol), pyridine (22 ml) and acetonitrile (25 ml) was stirred in an ice bath. Ethyl chloroformate (6.1 ml, 0.0638 mol) was added dropwise. The pink solution was stirred for 30 minutes at <10° C. The ice bath was replaced with an oil bath. The reaction mixture was heated to 95° C. and the volatiles were distilled off (43 ml). The reaction was cooled to room temperature, causing a white solid to form. The mixture was poured into water (100 ml) and acidified with concentrated aqueous hydrochloric acid. The resulting solid was filtered and recrystallized in hot ethanol to give 9.77 g of 6-chloro-2H-1,3-benzoxazine-2,4(3H)-dione.

Workup

  1. distillationthe volatiles were distilled off (43 ml)
  2. temperatureThe reaction was cooled to room temperature
  3. customto form
  4. filtrationThe resulting solid was filtered
  5. customrecrystallized in hot ethanol

Sources & evidence

ORD record
ord-f729aa9cc14044dab29f8e198728b14a
Source dataset
uspto-grants-2006_01
Patent number
US06991798B1

Reaction notes

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