Ethyl 2-cyanoacetimidate hydrochloride → 2-Amino-3-cyano-4H-[1]benzopyrano[4,3-b]pyrrole

HRID 610042Notes

Reaction equation

HRID 610042 reaction equation
[C:1]([CH2:3][C:4]([NH2:6])=[NH:5])#[N:2].Cl.C(CC(=N)OCC)#N.Br[CH:17]1[C:26](=O)[C:25]2[C:20](=[CH:21][CH:22]=[CH:23][CH:24]=2)[O:19][CH2:18]1>C(O)C>[NH2:5][C:4]1[NH:6][C:26]2[C:25]3[CH:24]=[CH:23][CH:22]=[CH:21][C:20]=3[O:19][CH2:18][C:17]=2[C:3]=1[C:1]#[N:2]

Participants

5

Reactant 3

HCID 12342543Ethyl 2-cyanoacetimidate hydrochlorideHCID 123873063-Bromochroman-4-oneHCID 220564242-Cyanoacetimidamide

Product 1

HCID 158712982-Amino-3-cyano-4H-[1]benzopyrano[4,3-b]pyrrole

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

To an ethanolic solution of 2-cyanoacetamidine prepared from ethyl 2-cyanoacetimidate hydrochloride (4.0 g) as in Reference Example 2 was added a solution of 3-bromo-4-chromanone (3.0 g) in ethanol dropwise under ice-cooling with stirring. The mixture was stirred at room temperature overnight and, then, concentrated under reduced pressure. The resulting crude product was dissolved in ethyl acetate. The ethyl acetate layer was washed with water, dried over MgSO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (Wakogel C-200, 200 g; eluent: 2% methanol/chloroform) and recrystallized from acetone/isopropyl ether to provide the title compound as light-brown crystals (0.31 g). m.p. 216-217° C.

Workup

  1. temperaturecooling
  2. stirringThe mixture was stirred at room temperature overnight
  3. concentrationconcentrated under reduced pressure
  4. dissolutionThe resulting crude product was dissolved in ethyl acetate
  5. washThe ethyl acetate layer was washed with water
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated under reduced pressure
  8. customThe residue was purified by silica gel column chromatography (Wakogel C-200, 200 g; eluent: 2% methanol/chloroform)
  9. customrecrystallized from acetone/isopropyl ether

Sources & evidence

ORD record
ord-2b383ca7e75547bda5b27a25803e8477
Source dataset
uspto-grants-1999_12
Patent number
US05998459

Reaction notes

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