Hydrochloric Acid → 1H,2H,4H-thieno(3,2-d)(1,3)oxazine-2,4-dione

HRID 223200Notes

Reaction equation

HRID 223200 reaction equation
Cl.[NH2:2][C:3]1[CH:7]=[CH:6][S:5][C:4]=1[C:8]([O:10][CH3:11])=[O:9].[OH-].[Na+].[Na].NC1C=CSC=1C(O)=[O:22].[Cl-].[Na+].Cl.C(Cl)(Cl)=O>O1CCCC1.O.C(O)CCC>[NH:2]1[C:3]2[CH:7]=[CH:6][S:5][C:4]=2[C:8](=[O:9])[O:10][C:11]1=[O:22]

Participants

11

Reactant 7

HCID 313Hydrochloric AcidHCID 5234Sodium ChlorideHCID 6371PhosgeneHCID 14798Sodium HydroxideHCID 15124973-Amino-2-thiophenecarboxylic acidHCID 5360545SodiumHCID 12517407Methyl 3-amino-2-thiophenecarboxylate hydrochloride

Product 1

HCID 27775521H,2H,4H-thieno(3,2-d)(1,3)oxazine-2,4-dione

Reagents, catalysts & solvents 3

HCID 2631-ButanolSolventHCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Procedure

A mixture of 175 g (0.93 mol) of methyl 3-amino-2-thiophenecarboxylate hydrochloride, 1.8 l of n-butanol and 77 g of sodium hydroxide is heated to boiling under reflux for 30 minutes. After concentration of the suspension obtained, the resulting mixture of sodium salt of 3-amino-2-thiophenecarboxylic acid and sodium chloride is used directly for the next step. For this purpose, the mixture is treated with 800 ml of water, 280 ml of concentrated hydrochloric acid and 230 ml of tetrahydrofuran. At 15° to 25° phosgene is conducted through this mixture and subsequently air is conducted through the mixture for 15 minutes. The precipitated solid material is filtered off under suction, washed with water and dried. There is obtained 2H-thieno[3,2-d][1,3]oxazine-2,4(1H)-dione of melting point 220°-221°.

Workup

  1. temperatureis heated
  2. temperatureunder reflux for 30 minutes
  3. customAfter concentration of the suspension obtained
  4. customAt 15° to 25°
  5. filtrationThe precipitated solid material is filtered off under suction
  6. washwashed with water
  7. customdried

Sources & evidence

ORD record
ord-0634a3d5e12646c5bb4c6c3b4fb46989
Source dataset
uspto-grants-1982_10
Patent number
US04352818

Reaction notes

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