Title: Benzopinacol
CAS Registry Number: 464-72-2
CAS Name: 1,1,2,2-Tetraphenyl-1,2-ethanediol
Additional Names: benzpinacone; tetraphenylethylene glycol
Molecular Formula: C26H22O2
Molecular Weight: 366.45
Percent Composition: C 85.22%, H 6.05%, O 8.73%
Line Formula: (C6H5)2C(OH)C(OH)(C6H5)2
Literature References: Prepd by photochemical reduction of benzophenone: Bachmann, Org. Synth. coll. vol. II, 71 (1943); L. F. Fieser, Organic Experiments (D. C. Heath & Co., Boston, 1964) p 203. By the action of phenylmagnesium bromide on benzil: Acree, Ber. 37, 2761 (1904).
Properties: Monoclinic prisms, may contain 1 mol C6H6 when crystallized from benzene. mp 197° (open capillary, rapid heating); mp 222° (copper block). On heating to mp it dec to benzophenone and benzohydrol. Soluble in 11.5 parts boiling glacial acetic acid; in 26 parts boiling benzene; in 39 parts boiling 95% alcohol. Freely sol in ether, carbon bisulfide, chloroform.
Melting point: mp 197° (open capillary, rapid heating); mp 222° (copper block)
Benzopurpurine 4B Benzoquinonium Chloride Benzoresorcinol Benzothiazole Benzotrichloride

The Pinacol coupling reaction

A pinacol coupling reaction is an organic reaction in which a carbon–carbon covalent bond is formed between the carbonyl groups of an aldehyde or a ketone in presence of an electron donor in a free radical process.[1] The reaction product is a vicinal diol. The reaction is named after pinacol (also known as 2,3-dimethyl-2,3-butanediol or tetramethylethylene glycol), which is the product of this reaction with acetone. The reaction is usually a homocoupling but intramolecular cross-coupling reactions are also possible. Pinacol was discovered by Wilhelm Rudolph Fittig in 1859.