Pyridine → 5-Methyl-5-trifluoromethylbarbituric acid

HRID 1657956Notes

Reaction equation

HRID 1657956 reaction equation
[NH2:1][C:2]([NH2:4])=[O:3].N1C=CC=CC=1.[CH3:11][C:12]([C:19]([F:22])([F:21])[F:20])([C:16](F)=[O:17])[C:13](F)=[O:14]>C(COC)OC>[CH3:11][C:12]1([C:19]([F:22])([F:21])[F:20])[C:16](=[O:17])[NH:4][C:2](=[O:3])[NH:1][C:13]1=[O:14]

Participants

5

Reactant 3

HCID 1049PyridineHCID 1176Urea2×HCID 21532246Methyltrifluoromethylmalonyl fluoride

Product 1

HCID 215322545-Methyl-5-trifluoromethylbarbituric acidYield 72.3%

Reagents, catalysts & solvents 1

HCID 80711,2-DimethoxyethaneSolvent2×

Procedure

To a suspension of 1.50 g (0.025 mol) of urea in 30 ml of glyme and 4.0 g (0.050 mol) of pyridine was added dropwise with stirring a solution of 5.0 g (0.026 mol) of methyltrifluoromethylmalonyl fluoride in 20 ml of glyme. Urea dissolved during a mildly exothermic reaction and the homogeneous solution was allowed to stand overnight. The mixture was then refluxed briefly, solvent was removed under vacuum, and the residue was stirred with 25 ml of water. Filtration and rinsing with water gave 3.80 g of 5-methyl-5-trifluoromethylbarbituric acid, mp 205°-206.5°C. A second crop, mp 205°-207°C, 0.84 g, brought the yield to 88% (4.64 g). Recrystallization from water gave an analytical sample, mp 205°-206°C; ir (KBr): 3.07 and 3.17 (NH), 5.67 shoulder and 5.80 (C=O), and 8-8.5 μ (CF); nmr ((CD3)2CO): 1H at ca. 7.0 (very broad, 2 (partly exchanged into acetone-d6), NH) and 1.72 ppm (quartet, JHF = 0.7 Hz, 3, CH3); 19F at -70.8 ppm (quartet, JHF = 0.7 Hz, CF3).

Workup

  1. additionwas added dropwise
  2. temperatureThe mixture was then refluxed briefly
  3. customsolvent was removed under vacuum
  4. filtrationFiltration
  5. washrinsing with water

Sources & evidence

ORD record
ord-86eb99c3aef14bef91314416ec370b12
Source dataset
uspto-grants-1976_06
Patent number
US03962325

Reaction notes

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