Maltol → ZINC 1-ethyl-3-hydroxypyrid-2-one

HRID 330064Notes

Reaction equation

HRID 330064 reaction equation
[Cl-].[Zn+2:2].[Cl-].[OH:4][C:5]1[C:6](=[O:11])[NH:7][CH:8]=[CH:9][CH:10]=1.[Zn].C(=O)([O-])[O-].[Na+].[Na+].[CH3:19][C:20]1OC=CC(=O)C=1O>C(O)C.C(Cl)(Cl)Cl>[CH2:19]([N:7]1[CH:8]=[CH:9][CH:10]=[C:5]([OH:4])[C:6]1=[O:11])[CH3:20].[Zn:2]

Participants

8

Reactant 5

HCID 8369MaltolHCID 10340Sodium CarbonateHCID 23994ZincHCID 281152,3-Dihydroxypyridine2×HCID 3007855Zincchloride

Product 1

HCID 70373874ZINC 1-ethyl-3-hydroxypyrid-2-one

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 6212ChloroformSolvent

Procedure

A chloroform solution of 1-ethyl-3-hydroxypyrid-2-one(3) is mixed with a 1M solution of zinc chloride in ethanol to provide a 2:1 molar ratio of hydroxypyridone:zinc in the mixture. After 5 minutes at 20° C., a 10 molar excess of solid sodium carbonate is added and the mixture is stirred for 10 minutes. The mixture is then filtered and the solvent evaporated to give the neutral complex containing the hydroxypyridone and Zn++ in a 2:1 proportion. Recrystallisation of the 2:1 complex from ethanol gives a white crystalline solid in essentially quantitative yield, m.p. 200° C. (with decomposition); νmax (1) 1620 cm-1 ; δ(d6DMSO), 6.80 (q, 1H), 6.30 (m, 2H), 4.01 (q, 2H), 3.3 (s, 3H), 1.23 (t, 3H).

Workup

  1. customto provide a 2
  2. filtrationThe mixture is then filtered
  3. customthe solvent evaporated
  4. customto give the neutral complex
  5. customRecrystallisation of the 2:1 complex from ethanol
  6. customgives a white crystalline solid in essentially quantitative yield, m.p. 200° C. (with decomposition)

Sources & evidence

ORD record
ord-672a697250f343d681febfe0f24a983b
Source dataset
uspto-grants-1990_01
Patent number
US04894455

Reaction notes

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