2,3-Diaminopyridine → 2-Methylpyrido[2,3-b]pyrazin-3(4H)-one

HRID 2172853Notes

Reaction equation

HRID 2172853 reaction equation
[C:1]([O:6]CC)(=O)[C:2]([CH3:4])=O.[NH2:9][C:10]1[C:15]([NH2:16])=[CH:14][CH:13]=[CH:12][N:11]=1>CO.CO.CO>[CH3:4][C:2]1[C:1](=[O:6])[NH:9][C:10]2[N:11]=[CH:12][CH:13]=[CH:14][C:15]=2[N:16]=1

Participants

5

Reactant 2

HCID 99562,3-DiaminopyridineHCID 12041Ethyl pyruvate

Product 1

HCID 149166492-Methylpyrido[2,3-b]pyrazin-3(4H)-one

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 18177619HCID 18177619, compoundSolvent

Procedure

Ethyl pyruvate (1.22 mL) was dissolved in methanol (10 mL) and added to a cold solution of 2,3-diaminopyridine (1.09 g) in methanol MeOH (20 mL) and the mixture was stirred at ambient temperature. The solid was filtered off and washed with cold methanol to afford 2-methyl-4H-pyrido[2,3-b]pyrazin-3-one (1.1 g) as a grey solid. 1.0 g of this material was suspended in acetonitrile (10 mL) and phosphoryl chloride (1.16 mL) was added. The mixture was heated at 120° C. for 0.5 h under MW conditions. The crude mixture was partitioned between water and EtOAc. The organic layer was washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo to afford IIId (460 mg) as a red solid sufficiently pure for the next step.

Workup

  1. filtrationThe solid was filtered off
  2. washwashed with cold methanol

Sources & evidence

ORD record
ord-232c88f2cf494981a54bfcfd5248c967
Source dataset
uspto-grants-2015_06
Patent number
US09056863B2

Reaction notes

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