Pyridine → 1,4,5,7-Tetrahydro-2-methyl-4-(2-nitrophenyl)-5-oxo-furo(3,4-b)pyridine-3-carboxylic acid, methyl ester

HRID 1285550Notes

Reaction equation

HRID 1285550 reaction equation
C1C=C[NH+]=CC=1.Br[Br-]Br.[CH3:10][C:11]1[NH:12][C:13](C)=[C:14]([C:30]([O:32][CH3:33])=[O:31])[CH:15]([C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][C:22]=2[N+:27]([O-:29])=[O:28])[C:16]=1[C:17]([O:19][CH3:20])=[O:18].N1C=CC=CC=1>C(Cl)(Cl)Cl>[CH3:10][C:11]1[NH:12][C:13]2[CH2:33][O:32][C:30](=[O:31])[C:14]=2[CH:15]([C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][C:22]=2[N+:27]([O-:29])=[O:28])[C:16]=1[C:17]([O:19][CH3:20])=[O:18]

Participants

4

Reactant 2

HCID 1049PyridineHCID 4485Nifedipine

Product 1

HCID 105925081,4,5,7-Tetrahydro-2-methyl-4-(2-nitrophenyl)-5-oxo-furo(3,4-b)pyridine-3-carboxylic acid, methyl esterYield 24%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent2×

Conditions

Temperature
0 °C

Procedure

In a similar manner, 2.77 grams of 80 percent pyridinium bromide perbromide (6.93 millimoles) was added in one portion to a cooled to 0° C. solution of 2.00 grams (5.77 millimoles) of dimethyl 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate (nifedipine), and 0.81 milliliter of pyridine in 40 milliliters of chloroform. The resulting mixture was stirred at 0° C. for 30 minutes, at reflux temperature for 90 minutes, allowed to cool to room temperature, diluted with chloroform, washed with 2N hydrochloric acid and with brine, dried, and the solvent vaporized in vacuo to obtain a crude product residue. The latter was flash chromatographed (J. Org. Chem. 43, 2923 (1978)) on silica gel employing 70 percent ethyl acetate--30 percent hexane as eluant to obtain 0.45 gram (24 percent yield) of purified methyl 2-methyl-4-(2-nitrophenyl)-5-oxo-1,4,5,7-tetrahydrofuro-[3,4-b]-pyridine-3-carboxylate product which after recrystallizing from ethyl acetate hexane had a melting point of 261°-263° C. (dec.). Elemental analyses were as follows:

Workup

  1. temperatureat reflux temperature for 90 minutes
  2. temperatureto cool to room temperature
  3. washwashed with 2N hydrochloric acid and with brine
  4. customdried
  5. customto obtain a crude product residue
  6. customchromatographed (J. Org. Chem. 43, 2923 (1978)) on silica gel employing 70 percent ethyl acetate--30 percent hexane as eluant

Sources & evidence

ORD record
ord-8c4e1b76c2234c3cba67435a198797f0
Source dataset
uspto-grants-1986_01
Patent number
US04567268

Reaction notes

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