Sulfuric Acid → HCID 13343680, compound

HRID 1154586Notes

Reaction equation

HRID 1154586 reaction equation
[Cl:1][C:2]1[CH:23]=[CH:22][CH:21]=[CH:20][C:3]=1[C:4]([C:6]1[C:7](Cl)=[C:8]([Cl:18])[C:9]2[O:13][CH:12]([C:14]([OH:16])=[O:15])[CH2:11][C:10]=2[CH:17]=1)=O.[O:24]1C2C=CC=CC=2C(C2C(Cl)=C(Cl)C3OC(C(O)=O)CC=3C=2)=[N:25]1.S(=O)(=O)(O)O>C(O)C>[Cl:18][C:8]1[C:7]2[O:24][N:25]=[C:4]([C:3]3[CH:20]=[CH:21][CH:22]=[CH:23][C:2]=3[Cl:1])[C:6]=2[CH:17]=[C:10]2[CH2:11][CH:12]([C:14]([OH:16])=[O:15])[O:13][C:9]=12

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 13343675HCID 13343675, compoundHCID 13343703HCID 13343703, compound

Product 1

HCID 13343680HCID 13343680, compound

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

8-Chloro-3-(o-chlorophenyl)-5,6-dihydrofuro[3,2-f]-1,2-benzisoxazole-6-carboxylic acid (4d) was prepared from (3d) using the procedure above; the product contained a significant impurity, presumably the countercyclized 5-(3-benzisoxazolyl)-6,7-dichloro-2,3-dihydrobenzofuran-2-carboxylic acid. The mixture was dissolved in 200 ml. absolute ethanol and treated with 0.5 ml. concentrated sulfuric acid overnight. The solution was then evaporated to dryness, redissolved in ethyl acetate, washed with brine, dried over anhydrous magnesium sulfate, and re-evaporated. Chromatography of the ester on silica gel with chloroform and n-hexane in a 3:1 ratio gave a solid, m.p. 136° C., which was determined by detailed mass spectral analysis to be the desired isomer. Hydrolysis at 60° C. in 25 ml. absolute ethanol and 200 ml. aqueous 1M sodium hydroxide for 20 minutes furnished a white precipitate which was distributed between ethyl acetate and 4.0 M aqueous hydrochloric acid, washed with brine, dried over anhydrous magnesium sulfate, and evaporated. Recrystallization from ethyl acetate with n-hexane gave (4 d), m.p. 224°-225° C., in 8.1% yield. Analysis (C16H9Cl2NO4) C,H,N,Cl.

Workup

  1. dissolutionThe mixture was dissolved in 200 ml
  2. customThe solution was then evaporated to dryness
  3. dissolutionredissolved in ethyl acetate
  4. washwashed with brine
  5. dry with materialdried over anhydrous magnesium sulfate
  6. customre-evaporated

Sources & evidence

ORD record
ord-52726d67efdd4d6aa65639a72ff484d8
Source dataset
uspto-grants-1984_12
Patent number
US04490384

Reaction notes

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