4-Hydroxybenzophenone

Chemical properties

white to beige fine crystalline powder

The Uses of 4-Hydroxybenzophenone

4-Hydroxybenzophenone is used in the field of organic synthesis. It is used as pharmaceutical intermediate of clomifene citrate.

The Uses of 4-Hydroxybenzophenone

Metabolite of benzophenone.

Preparation

Preparation by condensation of benzotrichloride,
? with phenol in the presence of aluminium chloride in carbon disulfide at 0° (90%) or in the presence of zinc oxide in a water bath;
? with p-bromophenol in 30% sodium hydroxide solution at 80–85° (81%). There is substitution of the bromine atom by the benzoyl group.

Definition

ChEBI: 4-Hydroxybenzophenone is a member of benzophenones.

Synthesis

4-Hydroxybenzophenone (4-HBP) was prepared by benzoylation of phenol at 493 K using benzoic anhydride as the benzoylating agent and zeolite H-beta as the catalyst, followed by Fries rearrangement. The conversion of benzoic anhydride was 95.3 wt%. The specific steps are as follows:
The benzoylation of phenol can be carried out through different reaction pathways. Phenol undergoes O-acylation with benzoic anhydride (BA) to rapidly generate PB. Further, PB is debenzoylated to generate phenol and benzoic acid (BAC). Phenol reacts with PB again through intermolecular reactions to generate 2-HBP and 4-HBP. In addition, 2-HBP and 4-HBP can be generated through different reaction pathways: through C-acylation of phenol with BA and intramolecular rearrangement of phenyl benzoate on zeolite H-beta (Fries rearrangement).^[1]

Synthesis Reference(s)

Journal of the American Chemical Society, 77, p. 4674, 1955 DOI: 10.1021/ja01622a074
The Journal of Organic Chemistry, 19, p. 978, 1954 DOI: 10.1021/jo01371a016
Tetrahedron Letters, 31, p. 3943, 1990 DOI: 10.1016/S0040-4039(00)97513-0

Flammability and Explosibility

Not classified

Purification Methods

Dissolve p-benzoylphenol in hot EtOH (charcoal), filter and cool. Alternatively crystallise it once from EtOH/H2O and twice from *benzene [Grunwald J Am Chem Soc 73 4934 1951, Dryland & Sheppard J Chem Soc Perkin Trans 1 125 1986]. [Beilstein 8 IV 1263.]

References

[1] V.D. CHAUBE. A Novel Single Step Selective Synthesis of 4-Hydroxybenzophenone (4-HBP) Using Zeolite H-Beta[J]. Catalysis Letters, 2002, 79 1-4: 89-94. DOI:10.1023/A:1015356324770.