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

HRID 10937Notes

Reaction equation

HRID 10937 reaction equation
ClS(O)(=O)=O.C(O)(=O)/C=C/C(O)=O.C(O)(=O)/C=C\C(O)=O.[N+:22]([C:25]1[CH:41]=[CH:40][CH:39]=[CH:38][C:26]=1[O:27]/[C:28](=[CH:33]\[C:34]([O:36]C)=O)/[C:29]([O:31][CH3:32])=[O:30])([O-:24])=[O:23].[N+](C1C=CC=CC=1O/C(=C/C(OC)=O)/C(OC)=O)([O-])=O>>[N+:22]([C:25]1[C:26]2[O:27][C:28]([C:29]([O:31][CH3:32])=[O:30])=[CH:33][C:34](=[O:36])[C:38]=2[CH:39]=[CH:40][CH:41]=1)([O-:24])=[O:23]

Participants

5

Reactant 4

HCID 24638Chlorosulfonic acidHCID 10308267Dimethyl 2-(2-nitrophenoxy)fumarateHCID 11357979Dimethyl 2-(2-nitrophenoxy)maleateHCID 86597595Fumaric acid maleic acid

Product 1

HCID 21982597Methyl 8-nitro-4-oxo-4H-1-benzopyran-2-carboxylateYield 86%

Conditions

Temperature
60 °C

Procedure

A reaction container equipped with a stirrer, a cooling tube and a thermometer was charged with 300 parts by weight of chlorosulfonic acid. Thereto, 60 parts by weight of a mixture (content: 81.1% by weight, fumaric acid/maleic acid ratio=57/43) containing 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 60° C. and the mixture was stirred and kept at the same temperature for 5 hours and at an inner temperature of 70° C. for 3 hours to obtain a reaction solution containing 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran (reaction yield: 86%). After cooled to room temperature, the reaction solution was poured gradually into 360 parts by weight of water. The mixture was kept at an inner temperature of 60° C. for 8 hours and then cooled to an inner temperature of 0° C. gradually. 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: 2.5% by weight; the content of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran: 96.7% by weight). The yield of 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran was 2% and the yield of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran was 73%.

Workup

  1. customA reaction container equipped with a stirrer, a cooling tube
  2. additionwas added dropwise at an inner temperature of 50° C. or below
  3. additionAfter completion of addition
  4. customto obtain a reaction solution

Sources & evidence

ORD record
ord-072c3d9de7de4b1389dab342867a40c5
Source dataset
uspto-grants-2006_08
Patent number
US07094914B2

Reaction notes

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