Benzophenone imine is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...
with the formula of (C
6H
5)
2C=NH. A pale yellow liquid, benzophenone imine is used as a
reagent in
organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...
.
Synthesis
Benzophenone imine can be prepared by the
thermal decomposition
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is req ...
of benzophenone
oxime
In organic chemistry, an oxime is a organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substitu ...
:
:2(C
6H
5)
2C=NOH → (C
6H
5)
2C=NH + (C
6H
5)
2C=O
Benzophenone imine can also be
synthesized by addition of
phenylmagnesium bromide
Phenylmagnesium bromide, with the simplified formula , is a magnesium-containing organometallic compound. It is commercially available as a solution in diethyl ether or tetrahydrofuran (THF). Phenylmagnesium bromide is a Grignard reagent. It i ...
to
benzonitrile
Benzonitrile is the chemical compound with the formula , abbreviated PhCN. This aromatic organic compound is a colorless liquid with a sweet bitter almond odour. It is mainly used as a precursor to the resin benzoguanamine.
Production
It is ...
followed by careful hydrolysis (lest the imine be hydrolyzed):
:C
6H
5CN + C
6H
5MgBr → (C
6H
5)
2C=NMgBr
:(C
6H
5)
2C=NMgBr + H
2O → (C
6H
5)
2C=NH + MgBr(OH)
This method is known as Moureu-Mignonac ketimine synthesis.
Yet another route to benzophenone imine involves reaction of benzophenone and ammonia.
Reactions
Benzophenone imine undergoes
deprotonation
Deprotonation (or dehydronation) is the removal (transfer) of a proton (or hydron, or hydrogen cation), (H+) from a Brønsted–Lowry acid in an acid–base reaction.Henry Jakubowski, Biochemistry Online Chapter 2A3, https://employees.csbsju. ...
with alkyl lithium reagents.
:(C
6H
5)
2C=NH + CH
3Li → (C
6H
5)
2C=NLi + CH
4
:(C
6H
5)
2C=NLi + CH
3I → (C
6H
5)
2C=NCH
3 + LiI
Primary amines can be protected as benzophenone imines, and the protected amines are stable in
flash chromatography
Column chromatography in chemistry is a chromatography method used to isolate a single chemical compound from a mixture. Chromatography is able to separate substances based on differential adsorption of compounds to the adsorbent; compounds move th ...
.
involves coupling aromatic halide and amine to form
carbon-nitrogen bonds with the help of
palladium
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself nam ...
-based
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
s. Benzophenone imine can be used as an ammonia-equivalent in such reactions.
[{{Cite journal, date=1997-09-08, title=An Ammonia Equivalent for the Palladium-Catalyzed Amination of Aryl Halides and Triflates, journal=Tetrahedron Letters, language=en, volume=38, issue=36, pages=6367–6370, doi=10.1016/S0040-4039(97)01465-2, issn=0040-4039, last1=Wolfe, first1=John P., last2=Åhman, first2=Jens, last3=Sadighi, first3=Joseph P., last4=Singer, first4=Robert A., last5=Buchwald, first5=Stephen L.]
References
Imines