Phthalyl-4-isothiocyanate → 5-Isothiocyanato-2-benzofuran-1,3-dione

HRID 1720188Notes

Reaction equation

HRID 1720188 reaction equation
[N:1]([C:4]1[CH:5]=[C:6]([C:13]([OH:15])=[O:14])[C:7](=[CH:11][CH:12]=1)[C:8]([OH:10])=O)=[C:2]=[S:3]>FC(F)(F)C(OC(=O)C(F)(F)F)=O.C(Cl)Cl>[N:1]([C:4]1[CH:5]=[C:6]2[C:13](=[O:14])[O:15][C:8](=[O:10])[C:7]2=[CH:11][CH:12]=1)=[C:2]=[S:3]

Participants

4

Reactant 1

HCID 191815Phthalyl-4-isothiocyanate

Product 1

HCID 540346455-Isothiocyanato-2-benzofuran-1,3-dione

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 9845Trifluoroacetic anhydrideSolvent

Procedure

The 4-isothiocyanatophthalic acid thus obtained was immediately heated to reflux in a mixture of trifluoroacetic anhydride and methylene chloride for 2 hours under a nitrogen atmosphere. After cooling to room temperature, the reaction mixture was concentrated under reduced pressure. Recrystallization of the resultant solid from 30 mL of carbon tetrachloride afforded 4-isothiocyanatophthalic anhydride as brownish-purple crystals in a yield of 2.3778 g, (77 percent of theoretical). The title compound melted at 106°-108° C.; 1H NMR (300 MHz, acetone-d6) d, 8.15 (d, J=8.1 Hz, 1H), 8.06 (d, J=1.7 Hz, 1H), 7.97 (dd, J=8.1, 1.7 Hz, 1H); 13C NMR (75 MHz, acetone-d6) d 163.3, 162.6, 139.8, 134.8, 134.6, 130.6, 128.2, 123.5, 111.6; IR (CHCl3) 2010 (br), 1840, 1740 cm-1; MS m/e 205, 161, 133 (base), 74.

Workup

  1. temperaturewas immediately heated
  2. concentrationthe reaction mixture was concentrated under reduced pressure
  3. customRecrystallization of the resultant solid from 30 mL of carbon tetrachloride

Sources & evidence

ORD record
ord-6170808c89b54db3afbd5bce63188d2e
Source dataset
uspto-grants-1996_04
Patent number
US05505931

Reaction notes

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