Benzophenone imine is an organic compound with the formula of (C6H5)2C=NH. A pale yellow liquid, benzophenone imine is used as a reagent in organic synthesis.[1]

Benzophenone imine
Names
Preferred IUPAC name
Diphenylmethanimine
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.103.715 Edit this at Wikidata
EC Number
  • 600-205-0
  • 440-870-2
UNII
  • InChI=1S/C13H11N/c14-13(11-7-3-1-4-8-11)12-9-5-2-6-10-12/h1-10,14H
    Key: SXZIXHOMFPUIRK-UHFFFAOYSA-N
  • C1=CC=C(C=C1)C(=N)C2=CC=CC=C2
Properties
C13H11N
Molar mass 181.238 g·mol−1
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319, H335
P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Synthesis

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Benzophenone imine can be prepared by the thermal decomposition of benzophenone oxime:[2]

2 (C6H5)2C=NOH → (C6H5)2C=NH + (C6H5)2C=O

Benzophenone imine can also be synthesized by addition of phenylmagnesium bromide to benzonitrile followed by careful hydrolysis (lest the imine be hydrolyzed):[3]

C6H5CN + C6H5MgBr → (C6H5)2C=NMgBr
(C6H5)2C=NMgBr + H2O → (C6H5)2C=NH + MgBr(OH)

This method is known as Moureu-Mignonac ketimine synthesis.[4] Yet another route to benzophenone imine involves reaction of benzophenone and ammonia.[5]

Reactions

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Benzophenone imine undergoes deprotonation with alkyl lithium reagents.[6]

(C6H5)2C=NH + CH3Li → (C6H5)2C=NLi + CH4
(C6H5)2C=NLi + CH3I → (C6H5)2C=NCH3 + LiI

Primary amines can be protected as benzophenone imines, and the protected amines are stable in flash chromatography.[7]

Buchwald-Hartwig amination involves coupling aromatic halide and amine to form carbon-nitrogen bonds with the help of palladium-based catalysts. Benzophenone imine can be used as an ammonia-equivalent in such reactions.[1]

References

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  1. ^ a b Wolfe, John P.; Åhman, Jens; Sadighi, Joseph P.; Singer, Robert A.; Buchwald, Stephen L. (1997-09-08). "An Ammonia Equivalent for the Palladium-Catalyzed Amination of Aryl Halides and Triflates". Tetrahedron Letters. 38 (36): 6367–6370. doi:10.1016/S0040-4039(97)01465-2. ISSN 0040-4039.
  2. ^ Arthur Lachman (1930). "Diphenylmethane Imine Hydrochloride". Organic Syntheses. 10: 28. doi:10.15227/orgsyn.010.0028.
  3. ^ Pickard, P. L.; Tolbert, T. L. (December 1961). "An Improved Method of Ketimine Synthesis". The Journal of Organic Chemistry. 26 (12): 4886–4888. doi:10.1021/jo01070a025. ISSN 0022-3263.
  4. ^ "Moureau-Mignonac Ketimine Synthesis". Hoboken, NJ, USA: John Wiley & Sons, Inc. 2010-09-15. pp. 1988–1990. doi:10.1002/9780470638859.conrr446. ISBN 9780470638859. {{cite book}}: |journal= ignored (help); Missing or empty |title= (help)
  5. ^ Verardo, G.; Giumanini, A. G.; Strazzolini, P.; Poiana, M. (1988). "Ketimines From Ketones and Ammonia". Synthetic Communications. 18 (13): 1501–1511. doi:10.1080/00397918808081307.
  6. ^ Nottingham, Chris; Lloyd-Jones, Guy C. (2018). "Trimethylsilyldiazo[13C]methane: A Versatile 13C-Labelling Reagent". Organic Syntheses. 95: 374–402. doi:10.15227/orgsyn.095.0374. hdl:20.500.11820/c801073c-6b4b-4a85-be68-2c4313b6e53d.
  7. ^ O'Donnell, Martin J. (2001-04-15). "Benzophenone Imine". Chichester, UK: John Wiley & Sons, Ltd. doi:10.1002/047084289x.rb031. ISBN 978-0471936237. {{cite book}}: |journal= ignored (help); Missing or empty |title= (help)