Methyl 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide → 2-methyl-3,4-dihydro-4-oxo-N-(4-oxo-4H-1-benzopyran-3-yl)-2H-1,2-benzothiazine-3-carboxamide

HRID 2286200Notes

Reaction equation

HRID 2286200 reaction equation
CO[C:3]([CH:5]1[C:10](=[O:11])[C:9]2[CH:12]=[CH:13][CH:14]=[CH:15][C:8]=2[S:7](=O)(=O)[N:6]1[CH3:18])=[O:4].[NH2:19][C:20]1[C:25](=[O:26])[C:24]2[CH:27]=[CH:28][CH:29]=[CH:30][C:23]=2[O:22][CH:21]=1>C1(C)C(C)=CC=CC=1>[CH3:18][N:6]1[CH:5]([C:3]([NH:19][C:20]2[C:25](=[O:26])[C:24]3[CH:27]=[CH:28][CH:29]=[CH:30][C:23]=3[O:22][CH:21]=2)=[O:4])[C:10](=[O:11])[C:9]2[CH:12]=[CH:13][CH:14]=[CH:15][C:8]=2[S:7]1

Participants

4

Reactant 2

HCID 120152Methyl 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxideHCID 122586463-Aminochromone

Product 1

HCID 205422242-methyl-3,4-dihydro-4-oxo-N-(4-oxo-4H-1-benzopyran-3-yl)-2H-1,2-benzothiazine-3-carboxamide

Reagents, catalysts & solvents 1

HCID 7237O-XyleneSolvent

Conditions

Temperature
50 °C

Procedure

A 500 ml round flask, which is connected to a distillation head and a condenser, is charged with 3.5 g (0.013 mole) of 2-methyl-3,4-dihydro-4-oxo-2H-1,2-benzothiazine-3-carboxylic acid methyl ester 1,1-dioxide, 2.1 g (0.013 mole) of 3-amino-4-oxo-4H-1-benzopyrane and 100 ml of dry xylene. Then nitrogen gas is blown into the resulting suspension for 5 minutes. The reaction mixture is subsequently subjected to a slow distillation lasting 15 hours, in the course of which procedure complete solution is attained after heating for only 10 minutes. The solvent is replaced every 2 hours. The reaction mixture is then cooled to 50° C. The precipitate which has formed is collected by filtration, washed with ethanol and dried, yielding 2-methyl-3,4-dihydro-4-oxo-N-(4-oxo-4H-1-benzopyran-3-yl)-2H-1,2-benzothiazine-3-carboxamide, 1,1-dioxide in the form of brownish crystals with a melting point of 290° C. (with decomp.).

Workup

  1. customA 500 ml round flask, which is connected to a distillation head and a condenser
  2. distillationThe reaction mixture is subsequently subjected to a slow distillation
  3. waitlasting 15 hours, in the course of which procedure complete solution
  4. temperatureafter heating for only 10 minutes
  5. waitThe solvent is replaced every 2 hours
  6. customThe precipitate which has formed
  7. filtrationis collected by filtration
  8. washwashed with ethanol
  9. customdried

Sources & evidence

ORD record
ord-e68cbfc29c3b41129715ee8d18acb887
Source dataset
uspto-grants-1982_04
Patent number
US04327091

Reaction notes

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