Diethyl squarate → 4-(2-Ethoxy-3,4-dioxo-cyclobut-1-enylamino)-3-ethylbenzonitrile

HRID 1733900

Reaction equation

HRID 1733900 reaction equation
[NH2:1][C:2]1[CH:9]=[CH:8][C:5]([C:6]#[N:7])=[CH:4][C:3]=1[CH2:10][CH3:11].[CH2:12]([O:14][C:15]1[C:16](=O)[C:17](=[O:22])[C:18]=1[O:19]CC)[CH3:13]>C(#N)C.C(OCC)(=O)C>[O:19]=[C:18]1[C:17](=[O:22])[C:16]([NH:1][C:2]2[CH:9]=[CH:8][C:5]([C:6]#[N:7])=[CH:4][C:3]=2[CH2:10][CH3:11])=[C:15]1[O:14][CH2:12][CH3:13]

Participants

5

Reactant 2

HCID 123228Diethyl squarate2×HCID 27353304-Amino-3-ethylbenzonitrile

Product 1

HCID 199729184-(2-Ethoxy-3,4-dioxo-cyclobut-1-enylamino)-3-ethylbenzonitrileYield 24%

Reagents, catalysts & solvents 2

HCID 6342AcetonitrileSolventHCID 8857Ethyl AcetateSolvent

Procedure

4-Amino-3-ethylbenzonitrile (2.00 g, 13.7 mmol) was added to a solution of 3,4-diethoxy-3-cyclobutene-1,2-dione (2.30 g, 13.5 mmol) in acetonitrile (5 mL). After refluxing the mixture for 24 h a second portion of 3,4-diethoxy-3-cyclobutene-1,2-dione (1.15 g, 6.76 mmol) was added and heating was continued for an additional 24 h. The reaction mixture was diluted with ethyl acetate (45 mL), stirred vigorously and filtered free of undissolved solid. The filtrate was concentrated and the resulting residue was purified by chromatographed (CH3OH/CH2Cl2) and trituration with ether to afford 0.86 g (24%) of product as a light yellow solid: 1H NMR (DMSO-d6): δ 10.57 (s, 1H), 7.77-7.66 (m, 2H), 7.31 (d, 1H), 4.71 (q, 2H), 2.73 (q, 2H), 1.37 (t, 3H), 1.13 (t, 3H).

Workup

  1. additionwas added
  2. temperatureheating
  3. filtrationfiltered free of undissolved solid
  4. concentrationThe filtrate was concentrated
  5. customthe resulting residue was purified
  6. customby chromatographed (CH3OH/CH2Cl2) and trituration with ether

Sources & evidence

ORD record
ord-cc97b40a15064c2d81a778b15be983aa
Source dataset
uspto-grants-1996_07
Patent number
US05532245

Linked notes

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