Acetic Acid → Ethyl 2-cyano-3-(7,8-dimethoxy-2H-1-benzopyran-5-yl)propanoate

HRID 34470

Reaction equation

HRID 34470 reaction equation
[C:1]([C:3](=[CH:9][C:10]1[C:15]2[CH:16]=[CH:17][CH2:18][O:19][C:14]=2[C:13]([O:20][CH3:21])=[C:12]([O:22][CH3:23])[CH:11]=1)[C:4]([O:6][CH2:7][CH3:8])=[O:5])#[N:2].C(O)(=O)C.CC1C(Br)=C(O)C(Br)=CC=1C1(C2C=C(Br)C(O)=C(Br)C=2C)OS(=O)(=O)C2C=CC=CC1=2.C([BH3-])#N.[Na+]>C(O)C>[C:1]([CH:3]([CH2:9][C:10]1[C:15]2[CH:16]=[CH:17][CH2:18][O:19][C:14]=2[C:13]([O:20][CH3:21])=[C:12]([O:22][CH3:23])[CH:11]=1)[C:4]([O:6][CH2:7][CH3:8])=[O:5])#[N:2]

Participants

6

Reactant 4

HCID 176Acetic Acid3×HCID 6451Bromocresol GreenHCID 5003444Sodium cyanoborohydrideHCID 54507081Ethyl 2-cyano-3-(7,8-dimethoxy-2H-1-benzopyran-5-yl)propenoate

Product 1

HCID 20129780Ethyl 2-cyano-3-(7,8-dimethoxy-2H-1-benzopyran-5-yl)propanoate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

A mixture of ethyl 2-cyano-3-(7,8-dimethoxy-2H-1-benzopyran-5-yl)propenoate (19.8 g, 0.63 mole) in ethanol (500 mL) under nitrogen was treated with acetic acid (4 mL) and a trace of bromocresol green and heated to reflux. Heating was discontinued and sodium cyanoborohydride (4.4 g, 0.07 mole) in ethanol (100 mL) was co-added with additional acetic acid (11 mL). The mixture was stirred under nitrogen for 2 hr, acetic acid (10 mL) added and the ethanol removed under reduced pressure. The resultant yellow solid was taken up in ethyl acetate (250 mL) and successively extracted with water (125 mL), saturated sodium bicarbonate (3×100 mL) and water (100 mL), then dried over magnesium sulfate. The volatiles were removed under reduced pressure to leave an amber oil, 18.22 g (91.4%) which was used without further purification.

Workup

  1. temperatureHeating
  2. customthe ethanol removed under reduced pressure
  3. extractionsuccessively extracted with water (125 mL), saturated sodium bicarbonate (3×100 mL) and water (100 mL)
  4. dry with materialdried over magnesium sulfate
  5. customThe volatiles were removed under reduced pressure
  6. customto leave an amber oil, 18.22 g (91.4%) which
  7. customwas used without further purification

Sources & evidence

ORD record
ord-62b182c93158406b8248468834a06f6a
Source dataset
uspto-grants-1988_08
Patent number
US04761475

Linked notes

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