Phosphorus oxychloride → Methyl 2-chlorothieno[2,3-b]pyrazine-6-carboxylate

HRID 1184829Notes

Reaction equation

HRID 1184829 reaction equation
O=[C:2]1[NH:7][C:6]2[CH:8]=[C:9]([C:11]([O:13][CH3:14])=[O:12])[S:10][C:5]=2[N:4]=[CH:3]1.P(Cl)(Cl)([Cl:17])=O>>[Cl:17][C:2]1[N:7]=[C:6]2[CH:8]=[C:9]([C:11]([O:13][CH3:14])=[O:12])[S:10][C:5]2=[N:4][CH:3]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 67125557Methyl 2-oxo-1,2-dihydrothieno[2,3-b]pyrazine-6-carboxylate

Product 1

HCID 86680165Methyl 2-chlorothieno[2,3-b]pyrazine-6-carboxylateYield 79%

Procedure

A solution of methyl 2-oxo-1,2-dihydrothieno[3,2-b]pyrazine-6-carboxylate 21 (0.35 g, 1.665 mmol) in phosphorus oxychloride (10 mL, 107 mmol) was stirred at 105° C. for 5 h. Evaporated to dryness. Dissolved in EtOAc and washed with NaHCO3 solution, brine, dried and evaporated to give crude methyl 2-chlorothieno[3,2-b]pyrazine-6-carboxylate 22 (299 mg, 79%). NMR (400 MHz, CDCl3) 4.02 (s, 3H), 8.11 (s, 1H), 8.61 (s, 1H). (m/z)=229 and 231 (M+H)+.

Workup

  1. customEvaporated to dryness
  2. dissolutionDissolved in EtOAc
  3. washwashed with NaHCO3 solution, brine
  4. customdried
  5. customevaporated

Sources & evidence

ORD record
ord-c6d6a81102a3456ea338b0f9ac380882
Source dataset
uspto-grants-2014_03
Patent number
US08669256B2

Reaction notes

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