Trimethyl orthoformate → 2,3-Dihydro-5-(4-nitrobenzoyl)oxy-2,2,4,6,7-pentamethyl-1-benzofuran-3-carboxylic acid, methyl ester

HRID 863604Notes

Reaction equation

HRID 863604 reaction equation
[N+:1]([C:4]1[CH:28]=[CH:27][C:7]([C:8]([O:10][C:11]2[C:12]([CH3:26])=[C:13](C)[C:14]3[O:19][C:18]([CH3:21])([CH3:20])[CH2:17][C:16](=O)[C:15]=3[C:23]=2[CH3:24])=[O:9])=[CH:6][CH:5]=1)([O-:3])=[O:2].O.O.O.[N+]([O-])([O-])=O.[Tl+3].[N+]([O-])([O-])=O.[N+]([O-])([O-])=O.CO[CH:47]([O:50]C)[O:48][CH3:49]>CO>[N+:1]([C:4]1[CH:5]=[CH:6][C:7]([C:8]([O:10][C:11]2[C:23]([CH3:24])=[C:15]([CH3:16])[C:14]3[O:19][C:18]([CH3:20])([CH3:17])[CH:21]([C:47]([O:48][CH3:49])=[O:50])[C:13]=3[C:12]=2[CH3:26])=[O:9])=[CH:27][CH:28]=1)([O-:3])=[O:2]

Participants

5

Reactant 3

HCID 9005Trimethyl orthoformateHCID 11270721Nitric acid,thallium(3+) salt, trihydrate (9CI)HCID 152275713,4-dihydro-6-(4-nitrobenzoyl)oxy-2,2,5,7,8-pentamethyl-2H-1-benzopyran-4-one

Product 1

HCID 103416402,3-Dihydro-5-(4-nitrobenzoyl)oxy-2,2,4,6,7-pentamethyl-1-benzofuran-3-carboxylic acid, methyl esterYield 84%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A heterogeneous mixture of 30.20 g (0.079 mol) of 3,4-dihydro-6-(4-nitrobenzoyl)oxy-2,2,5,7,8-pentamethyl-2H-1-benzopyran-4-one, 36.86 g (0.083 m) of thallium (III) nitrate trihydrate, 200 ml of trimethylorthoformate, and 200 ml of methanol is stirred at room temperature for 4 days. The resulting solid is collected and washed with methanol. The residue is slurried in 100 ml of chloroform and filtered; this process is repeated three times. The combined filtrates are heated to boiling and the chloroform is gradually replaced by an equal volume of methanol until crystallization occurs to give 27.44 g (84%) of 2,3-dihydro-5-(4-nitrobenzoyl)oxy-2,2,4,6,7-pentamethyl-1-benzofuran-3-carboxylic acid, methyl ester, m.p. 215°-216° C. Elemental analysis, IR, UV, and 1H-NMR spectra confirm the structure. This procedure was scaled up to 402 g, and 380.9 g (87.8%) of product was obtained.

Workup

  1. customThe resulting solid is collected
  2. washwashed with methanol
  3. filtrationfiltered
  4. temperatureThe combined filtrates are heated
  5. customthe chloroform is gradually replaced by an equal volume of methanol until crystallization

Sources & evidence

ORD record
ord-e5e9d4ee00d8445eb5862852d81578fb
Source dataset
uspto-grants-1998_02
Patent number
US05721233

Reaction notes

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