Sulfuric Acid → 2-Chloro-3-(p-methoxyphenyl)-2-cyclobuten-1-one

HRID 258961Notes

Reaction equation

HRID 258961 reaction equation
[Cl:1][C:2]1[C:3](F)(F)[CH2:4][C:5]=1[C:6]1[CH:11]=[CH:10][C:9]([O:12][CH3:13])=[CH:8][CH:7]=1.[OH:16]S(O)(=O)=O>>[Cl:1][C:2]1[C:3](=[O:16])[CH2:4][C:5]=1[C:6]1[CH:11]=[CH:10][C:9]([O:12][CH3:13])=[CH:8][CH:7]=1

Participants

3

Reactant 2

HCID 1118Sulfuric AcidHCID 214251982-Chloro-1,1-difluoro-3-(p-methoxyphenyl)-2-cyclobutene

Product 1

HCID 214251912-Chloro-3-(p-methoxyphenyl)-2-cyclobuten-1-one

Procedure

2Chloro-1,1-difluoro-3-(p-methoxyphenyl)-2-cyclobutene (215 g., 0.93 mole) is poured gradually into 272 ml. of concentrated H2SO4 with stirring. The rate of addition is adjusted to maintain the reaction temperature below 40° C. When the reaction subsides, the cooling bath is removed, but stirring is continued for 20 min. The mixture is poured into 3 l. of water. A precipitate forms, and is collected on a filter, washed with water, and air-dried. recrystallization of this material twice from i-PrOH yields 128.8 g. (66%) of the desired intermediate, m.p. 96°-98° C. An analytical sample was prepared by chromatography an alumina (benzene) and recrystallized from heptane, m.p. 98-100° C.

Workup

  1. additionThe rate of addition
  2. temperatureto maintain the reaction temperature below 40° C
  3. customWhen the reaction subsides
  4. customthe cooling bath is removed
  5. additionThe mixture is poured into 3 l
  6. customA precipitate forms, and is collected on a filter
  7. washwashed with water
  8. customair-dried
  9. customrecrystallization of this material twice from i-PrOH
  10. customyields 128.8 g
  11. customAn analytical sample was prepared by chromatography an alumina (benzene)
  12. customrecrystallized from heptane, m.p. 98-100° C.

Sources & evidence

ORD record
ord-aa80b091b54c455a9aeaa1bf6c454da6
Source dataset
uspto-grants-1977_07
Patent number
US04035426

Reaction notes

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