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

HRID 10935Notes

Reaction equation

HRID 10935 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:43]=[CH:42][CH:41]=[CH:40][C:26]=1[O:27]/[C:28](=[CH:34]\[C:35]([O:37]CC)=O)/[C:29]([O:31][CH2:32][CH3:33])=[O:30])([O-:24])=[O:23].[N+](C1C=CC=CC=1O/C(=C/C(OCC)=O)/C(OCC)=O)([O-])=O>>[N+:22]([C:25]1[C:26]2[O:27][C:28]([C:29]([O:31][CH2:32][CH3:33])=[O:30])=[CH:34][C:35](=[O:37])[C:40]=2[CH:41]=[CH:42][CH:43]=1)([O-:24])=[O:23]

Participants

5

Reactant 4

HCID 24638Chlorosulfonic acidHCID 11961493Diethyl 2-(2-nitrophenoxy)fumarateHCID 21982566Diethyl 2-(2-nitrophenoxy)maleateHCID 86597595Fumaric acid maleic acid

Product 1

HCID 100840998-nitro-2-ethoxycarbonyl-4-oxo-4H-1-benzopyranYield 70%

Conditions

Temperature
70 °C

Procedure

After a reaction container equipped with a stirrer, a cooling tube and a thermometer was charged with 15 parts by weight of chlorosulfonic acid, 3 parts by weight of a mixture (content: 84.4% by weight, fumaric acid/maleic acid ratio=49/51) containing diethyl 2-(2-nitrophenoxy)fumarate and diethyl 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 7 hours to obtain a reaction solution containing 8-nitro-2-ethoxycarbonyl-4-oxo-4H-1-benzopyran (reaction yield: 70%). After cooled to room temperature, the reaction solution was gradually added into 24 parts by weight of water. After kept at an inner temperature of 60° C. for 1 hour, the mixture was gradually cooled to an inner temperature of 0° C. Precipitated crystals were filtered and dried to obtain 1.3 parts by weight of a crystalline mixture containing 8-nitro-2-ethoxycarbonyl-4-oxo-4H-1-benzopyran and 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran (the content of 8-nitro-2-ethoxycarbonyl-4-oxo-4H-1-benzopyran: 0.1% by weight; the content of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran: 86.4% by weight). The yield of 8-nitro-2-ethoxycarbonyl-4-oxo-4H-1-benzopyran was 0.1% and the yield of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran was 64%.

Workup

  1. customAfter a 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-82b9fddd628e4a618f9e86e30cf66450
Source dataset
uspto-grants-2006_08
Patent number
US07094914B2

Reaction notes

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