Diethyl (cyanomethyl)phosphonate → 3-(2,3-Dihydrobenzo[1,4]dioxin-6-yl)-3-(3,5-dimethoxyphenyl)acrylonitrile

HRID 970956Notes

Reaction equation

HRID 970956 reaction equation
C(OP([CH2:9][C:10]#[N:11])(=O)OCC)C.C[Si]([N-][Si](C)(C)C)(C)C.[Li+].[O:22]1[C:27]2[CH:28]=[CH:29][C:30]([C:32]([C:34]3[CH:39]=[C:38]([O:40][CH3:41])[CH:37]=[C:36]([O:42][CH3:43])[CH:35]=3)=O)=[CH:31][C:26]=2[O:25][CH2:24][CH2:23]1>C1COCC1>[O:22]1[C:27]2[CH:28]=[CH:29][C:30]([C:32]([C:34]3[CH:39]=[C:38]([O:40][CH3:41])[CH:37]=[C:36]([O:42][CH3:43])[CH:35]=3)=[CH:9][C:10]#[N:11])=[CH:31][C:26]=2[O:25][CH2:24][CH2:23]1

Participants

5

Reactant 3

HCID 75676Diethyl (cyanomethyl)phosphonateHCID 2733832Lithium HexamethyldisilazideHCID 69203673HCID 69203673, compound

Product 1

HCID 692032153-(2,3-Dihydrobenzo[1,4]dioxin-6-yl)-3-(3,5-dimethoxyphenyl)acrylonitrileYield 88.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a stirred solution of cyanomethylphosphonic acid diethyl ester (1.08 ml, 6.86 mmol) in anhydrous THF (10 ml) in an ice bath was added lithium bis-(trimethylsilyl)amide (1.0 M solution in THF, 6.86 ml, 6.86 mmol) slowly. The mixture was stirred at rt for 40 min, before a solution of (2,3-dihydrobenzo[1,4]dioxin-6-yl)-(3,5-dimethoxyphenyl)methanone (1.03 g, 3.43 mmol) in anhydrous THF (20 ml) was added. The mixture was refluxed overnight. The solution was poured into ice water (20 ml) and the two phases were separated. The THF phase was evaporated and combined with the aqueous phase, which were then extracted with CH2Cl2 (2×40 ml), washed with water (50 ml), dried over MgSO4, filtered and concentrated in vacuo to an oil, which was purified via flash column chromatography 5% EtOAc in hexane gradient to 25% EtOAc in hexane) to give 3-(2,3-dihydro-benzo[1,4]dioxin-6-yl)-3-(3,5-dimethoxy-phenyl)-acrylonitrile as an oil (0.98 g, 88%): 1H NMR (DMSO-d6) δ 6.99-6.79 (m, 3H, Ar), 6.65-6.62 (2ts, 1H, Ar), 6.46-6.44 (2ds, 2H, Ar), 6.25 (s, 0.47H, double bond proton of one isomer), 6.20 (s, 0.54H, double bond proton of the other isomer), 4.33-4.24 (m, 4H, 2CH2), 3.76 (s, 3H, OCH3), 3.74 (s, 3H, OCH3); 13C NMR (DMSO-d6) δ 179.5, 160.8, 160.7, 145.7, 144.8, 143.3, 143.0, 140.3, 139.1, 130.4, 129.7, 122.5, 121.7, 118.2, 118.1, 117.9, 117.2, 117.1, 116.6, 107.1, 106.7, 101.8, 100.9, 95.4, 94.3, 64.4, 64.2, 64.0, 64.0, 55.4, 54.9; Anal. Calcd. For C19H17NO4 (+0.05 H2O): C, 69.40; H, 5.26; N, 4.24. Found: C, 69.19; H, 5.11; N, 4.25.

Workup

  1. additionwas added
  2. temperatureThe mixture was refluxed overnight
  3. customthe two phases were separated
  4. customThe THF phase was evaporated
  5. extractionwere then extracted with CH2Cl2 (2×40 ml)
  6. washwashed with water (50 ml)
  7. dry with materialdried over MgSO4
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo to an oil, which
  10. customwas purified via flash column chromatography 5% EtOAc in hexane gradient to 25% EtOAc in hexane)

Sources & evidence

ORD record
ord-7c81c9a0fa804802b7b3704a717802cc
Source dataset
uspto-grants-2007_12
Patent number
US07312241B2

Reaction notes

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