Chlorosulfonic acid → Methyl 8-nitro-4-oxo-4H-1-benzopyran-2-carboxylate

HRID 10933Notes

Reaction equation

HRID 10933 reaction equation
ClS(O)(=O)=O.[N+:6]([C:9]1[CH:25]=[CH:24][CH:23]=[CH:22][C:10]=1[O:11]/[C:12](=[CH:17]\[C:18]([O:20]C)=O)/[C:13]([O:15][CH3:16])=[O:14])([O-:8])=[O:7].[N+](C1C=CC=CC=1O/C(=C/C(OC)=O)/C(OC)=O)([O-])=O>>[N+:6]([C:9]1[C:10]2[O:11][C:12]([C:13]([O:15][CH3:16])=[O:14])=[CH:17][C:18](=[O:20])[C:22]=2[CH:23]=[CH:24][CH:25]=1)([O-:8])=[O:7]

Participants

4

Reactant 3

HCID 24638Chlorosulfonic acidHCID 10308267Dimethyl 2-(2-nitrophenoxy)fumarateHCID 11357979Dimethyl 2-(2-nitrophenoxy)maleate

Product 1

HCID 21982597Methyl 8-nitro-4-oxo-4H-1-benzopyran-2-carboxylateYield 92%

Conditions

Temperature
70 °C

Procedure

A reaction container equipped with a stirrer, a cooling tube and a thermometer was charged with 250 parts by weight of chlorosulfonic acid. Thereto, 50 parts by weight of a mixture (content: 82.1% by weight, fumaric acid/maleic acid ratio=58/42) of dimethyl 2-(2-nitrophenoxy)fumarate and dimethyl 2-(2-nitrophenoxy)maleate was added dropwise at an inner temperature of 50° C. or below. After completion of addition, the inner temperature was raised to 70° C. and the mixture was stirred and kept at the same temperature for 6 hours to obtain a reaction solution containing 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran (reaction yield: 92%). After cooled to room temperature, the reaction solution was gradually added into 300 parts by weight of water. The mixture was kept at an inner temperature of 60° C. for 1 hour and then gradually cooled to an inner temperature of 0° C. Precipitated crystals were filtered and dried to obtain 30 parts by weight of a crystalline mixture of 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran and 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran (the content of 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran: 58.5% by weight; the content of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran: 39.8% by weight). The yield of 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran was 32% and the yield of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran was 50%.

Workup

  1. customA reaction container equipped with a stirrer, a cooling tube
  2. additionAfter completion of addition
  3. customto obtain a reaction solution

Sources & evidence

ORD record
ord-943639b9c51d44ceb787ea43af14469e
Source dataset
uspto-grants-2006_08
Patent number
US07094914B2

Reaction notes

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