Sulfuric Acid → Methyl 8-nitro-4-oxo-4H-1-benzopyran-2-carboxylate

HRID 10939Notes

Reaction equation

HRID 10939 reaction equation
ClS(O)(=O)=O.S(=O)(=O)(O)O.C(O)(=O)/C=C/C(O)=O.C(O)(=O)/C=C\C(O)=O.[N+:27]([C:30]1[CH:46]=[CH:45][CH:44]=[CH:43][C:31]=1[O:32]/[C:33](=[CH:38]\[C:39]([O:41]C)=O)/[C:34]([O:36][CH3:37])=[O:35])([O-:29])=[O:28].[N+](C1C=CC=CC=1O/C(=C/C(OC)=O)/C(OC)=O)([O-])=O>>[N+:27]([C:30]1[C:31]2[O:32][C:33]([C:34]([O:36][CH3:37])=[O:35])=[CH:38][C:39](=[O:41])[C:43]=2[CH:44]=[CH:45][CH:46]=1)([O-:29])=[O:28]

Participants

6

Reactant 5

HCID 1118Sulfuric AcidHCID 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 88%

Conditions

Temperature
60 °C

Procedure

A reaction container equipped with a stirrer, a cooling tube and a thermometer was charged with 50.2 parts by weight of chlorosulfonic acid. Thereto, 25.0 parts by weight of 98% sulfuric acid was added dropwise over 1 hour and the mixture was then warmed to 60° C. Thereto, 25.3 parts by weight of the mixture (content: 89.6% by weight, fumaric acid/maleic acid ratio=54/46) containing dimethyl 2-(2-nitrophenoxy)fumarate and dimethyl 2-(2-nitrophenoxy)maleate obtained in Example 10 was added dropwise at an inner temperature of 60° C. over 4 hours. After completion of addition, the inner temperature was raised to 95° C. and the mixture was stirred and kept at the same temperature for 4 hours to obtain a reaction solution containing 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran (reaction yield: 88%). The reaction solution was poured gradually into 113 parts by weight of water at 85° C. or below. The mixture was kept at an inner temperature of 85° C. for 6 hours and then cooled gradually to an inner temperature of 25° C. Precipitated crystals were filtered and dried to obtain 16.3 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: 13.8% by weight; the content of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran: 84.6% by weight). The yield of 8-nitro-2-methoxycarbonyl-4-oxo-4H-1-benzopyran was 11.5% and the yield of 8-nitro-2-carboxy-4-oxo-4H-1-benzopyran was 74.0%.

Workup

  1. customA reaction container equipped with a stirrer, a cooling tube
  2. additionwas added dropwise at an inner temperature of 60° C. over 4 hours
  3. additionAfter completion of addition
  4. temperaturethe inner temperature was raised to 95° C.
  5. customto obtain a reaction solution

Sources & evidence

ORD record
ord-b42345baf61644a1b75b6e3ae9158f01
Source dataset
uspto-grants-2006_08
Patent number
US07094914B2

Reaction notes

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