Acetone → 2,2-dimethyl-4-oxo-4H-1,3-benzodioxine-6-carbonitrile

Reaction equation

[C:1]([C:3]1[CH:11]=[C:7]([C:8]([OH:10])=[O:9])[C:6]([OH:12])=[CH:5][CH:4]=1)#[N:2].C(OC(C(F)(F)F)=O)(C(F)(F)F)=O.[CH3:26][C:27]([CH3:29])=O>>[CH3:26][C:27]1([CH3:29])[O:12][C:6]2[CH:5]=[CH:4][C:3]([C:1]#[N:2])=[CH:11][C:7]=2[C:8](=[O:10])[O:9]1

Participants

Reactant 3

HCID 180Acetone2×

HCID 9845Trifluoroacetic anhydride

HCID 130269355-Cyano-2-hydroxybenzoic acid

Product 1

HCID 597024522,2-dimethyl-4-oxo-4H-1,3-benzodioxine-6-carbonitrileYield 15%

Procedure

To a suspension of 5-cyano salicylic acid (60 g, 0.368 mol) in TEA (134 mL, 1.76 mol) and TFAA (45 mL, 0.32 mol) was added dry acetone (20 mL) and heated to reflux. After each 1 h interval was added 15 mL of dry acetone for 4 times and the reflux continued for 20 h. The reaction mixture was concentrated under vacuum and crude purified by flash column chromatography over silica gel (230-400 mesh) using CH2Cl2 as an eluent to give the title compound as a white solid (12 g, 15%). TLC: CH2Cl2 (100%), Rf: 0.5