Hydrochloric Acid → 1H-Pyrrole-2,3-dicarboxylic acid, 4,5-diphenyl-, dimethyl ester

HRID 1156303Notes

Reaction equation

HRID 1156303 reaction equation
Cl.[C:2]1([C:8]([CH:10]([NH2:17])[C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=O)[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[C:18]([C:24]([O:26][CH3:27])=[O:25])#[C:19][C:20]([O:22][CH3:23])=[O:21].C([O-])(=O)C.[Na+].Cl.[Na]>O.CO>[C:2]1([C:8]2[C:18]([C:24]([O:26][CH3:27])=[O:25])=[C:19]([C:20]([O:22][CH3:23])=[O:21])[NH:17][C:10]=2[C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

8

Reactant 5

HCID 313Hydrochloric AcidHCID 12980Dimethyl acetylenedicarboxylate2×HCID 517045Sodium AcetateHCID 5360545SodiumHCID 12306985885-75-6

Product 1

HCID 111750581H-Pyrrole-2,3-dicarboxylic acid, 4,5-diphenyl-, dimethyl esterYield 63%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

In a 2 l RB 3-neck flask with mechanical stirrer and condenser was placed 76.7 g (0.31 mole) of desyl amine hydrochloride [Pschorr et al, Chem. Ber., 35, 2740 (1902)], 750 ml methanol, 88 g (0.62 mole) dimethyl acetylenedicarboxylate (freshly distilled) and 61 g (0.75 mole) anhydrous sodium acetate. The mixture was heated at reflux for two hours. Then another 44 g (0.31 mole) of dimethyl acetylenedicarboxylate was added, and heating continued another two hours. While the reaction mixture was still at reflux, concentrated hydrochloric acid (~60 ml, to pH~2) was added dropwise. The mixture was heated at reflux another hour, then poured into 2 l water containing 200 ml 10% sodium bicarbonate solution. With stirring, more sodium bicarbonte was added until the solution was neutral. The gummy solid which precipitated was collected and washed with water. Trituration of this gummy material with ~500 ml of 50% aqueous ethanol gave a tan powdery solid, which was recrystallized from ~85% aqueous ethanol to give 65.5 g (63%) of white crystals, m.p. 191°-2° [Lit. m.p. 185°-7°; J. B. Hendrickson et al, J. Am. Chem. Soc., 86, 107 (1964)].

Workup

  1. customIn a 2 l RB 3-neck flask with mechanical stirrer and condenser was placed
  2. temperatureThe mixture was heated
  3. temperatureat reflux for two hours
  4. temperatureheating
  5. temperatureat reflux
  6. temperatureThe mixture was heated
  7. temperatureat reflux another hour
  8. customThe gummy solid which precipitated
  9. customwas collected
  10. washwashed with water
  11. customTrituration of this gummy material with ~500 ml of 50% aqueous ethanol gave a tan powdery solid, which
  12. customwas recrystallized from ~85% aqueous ethanol

Sources & evidence

ORD record
ord-bddb68a87863445fb2daef9d1ebb390e
Source dataset
uspto-grants-1982_06
Patent number
US04335136

Reaction notes

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