Triethylamine → 6,7-Dichloro-4-ethyl-3,4-dihydro-2H-pyrazino(2,3-b)(1,4)oxazine

HRID 437028

Reaction equation

HRID 437028 reaction equation
Cl[C:2]1[N:7]=[C:6]([Cl:8])[C:5]([Cl:9])=[N:4][C:3]=1Cl.[CH2:11]([NH:13][CH:14](O)[CH3:15])[CH3:12].[OH-].[K+].[O:19]1C=CC=CN1.C(N(CC)CC)C>C1C=CC=CC=1.C1COCC1>[Cl:9][C:5]1[C:6]([Cl:8])=[N:7][C:2]2[O:19][CH2:12][CH2:11][N:13]([CH2:14][CH3:15])[C:3]=2[N:4]=1

Participants

8

Reactant 5

HCID 8471TriethylamineHCID 14797Potassium HydroxideHCID 311820TetrachloropyrazineHCID 12313776OxazineHCID 18179409Ethylaminoethanol

Product 1

HCID 214299396,7-Dichloro-4-ethyl-3,4-dihydro-2H-pyrazino(2,3-b)(1,4)oxazineYield 12%

Reagents, catalysts & solvents 2

HCID 241BenzeneSolventHCID 8028TetrahydrofuranSolvent

Procedure

Tetrachloropyrazine (22 g, 0.1 mol), ethylaminoethanol (9 g, 0.1 mol), and crushed KOH (16.5 g, 85% assay, 0.25 mol) were contacted overnight in 200 ml of refluxing benzene. Work-up gave a mixture of the oxazine (25%) and of the O-adduct (75%). The mixture was dissolved in THF and triethylamine (20 g, 0.2 mol) was added and held at reflux temperature for 6 days. The solid was filtered, the THF rotary evaporated, and the residual oil was partitioned between water and CH2Cl2. The organic layer was dried (MgSO4) and rotary evaporated to leave an oily residue. This was recrystallized from hexane and IPA to give two crops totaling 2.8 g (12% yield), m.p. 108°-10°.

Workup

  1. customWork-up gave
  2. temperatureat reflux temperature for 6 days
  3. filtrationThe solid was filtered
  4. customthe THF rotary evaporated, and the residual oil was partitioned between water and CH2Cl2
  5. dry with materialThe organic layer was dried (MgSO4)
  6. customrotary evaporated
  7. customto leave an oily residue
  8. customThis was recrystallized from hexane and IPA
  9. customto give two crops

Sources & evidence

ORD record
ord-35cd28cf629c4e9284f7530a8a2b9bbb
Source dataset
uspto-grants-1977_06
Patent number
US04029657

Linked notes

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