Synthesis of benzophenones

Li C, Liu W, Zhao Z (2007) Efficient synthesis of benzophenone derivatives in Lewis acid ionic liquids. Catal Commun 8 1834-1837... 

Fig. (2). General pathway for the synthesis of benzophenones Adapled from [6,9]...

M. Luong, C.E. Domini, G.F. Silbestri, A.B. Chopa, Ultrasound-assisted synthesis of benzophenones by Stifle cross-coupling reactions. Optimization via experimental design, J. Orgmetal. Chem. 723 (2013) 43-48. 

An ingenious synthesis of 1-arylisoindolcs has been developed by Vebor and Lwowski, based upon the reaction of an o-phthalimido-methylbenzophenone (41, R = aryl) with hydrazine (Table IV). The benzophenone is prepared by a Friedel-Crafts reaction with o-phthalimidomethylbenzoyl chloride (40). The mechanism of isoindole formation can be represented sehematically by a sequence involving attack by hydrazine at the imide to give the ring-opened hj drazide (42), followed by cyclization to phthalazine-l,4-dione (44) with displacement of the o-aminomethylbenzophenone (43). Intramolecular condensation of the latter can lead, via the isoindolenine... 

The intermolecular McMurry reaction is first of all a suitable method for the synthesis of symmetrical alkenes. With a mixture of carbonyl compounds as starting material, the yield is often poor. An exception to this being the coupling of diaryl ketones with other carbonyl compounds, where the mixed coupling product can be obtained in good yield. For example benzophenone and acetone (stoichiometric ratio 1 4) are coupled in 94% yield. ... 

Intramolecular arylations can also be carried out photochemically. Huisgen and Zahler (1963 a) prepared fluoren-9-one by irradiation of benzophenone-diazonium salts in dilute sulfuric acid. The classical Pschorr synthesis of phenanthrene-9-carb-... 

The Ullman reaction has long been known as a method for the synthesis of aromatic ethers by the reaction of a phenol with an aromatic halide in the presence of a copper compound as a catalyst. It is a variation on the nucleophilic substitution reaction since a phenolic salt reacts with the halide. Nonactivated aromatic halides can be used in the synthesis of poly(arylene edier)s, dius providing a way of obtaining structures not available by the conventional nucleophilic route. The ease of halogen displacement was found to be the reverse of that observed for activated nucleophilic substitution reaction, that is, I > Br > Cl F. The polymerizations are conducted in benzophenone with a cuprous chloride-pyridine complex as a catalyst. Bromine compounds are the favored reactants.53,124 127 Poly(arylene ether)s have been prepared by Ullman coupling of bisphenols and... 

Poly(2,5-benzophenone), synthesis of, 492 Polybenzothiazole, synthesis of, 314-319 Polybenzoxazoles, synthesis of, 292, 314-319... 

More recently, catalytic asymmetric allylations of imines and imine derivatives in aqueous media have been studied. An /V-spiro C2-symmetrical chiral quaternary ammonium salt (5,5)-I-Br (,S, .S )-()-Np-NAS-Br] has been evaluated in the allylation of glycine tert-Bu ester benzophenone Schiff base [Ph2C=NCH2COOCMe3] for synthesis of both natural and unnatural a-amino acids (Eq. 11,45).76... 

Scheme 39. Synthesis of norchelerythrine (222) by photocyclization. Reagents a, KOBu, benzophenone, dioxane b, CH2N2, CH2C12 c, hv, benzene.

The products of such reactions can be useful intermediates in the synthesis of commercial drugs. The nature of the substituents within the benzophenones has an effect on rate, with electron-withdrawing groups favoring the reaction more than electron-donating groups. For example, kinetic studies showed that p-trifluoromethylbenzophenone was hydrogenated 11-fold faster than the p-... 

Scheme 22 Solid-phase synthesis of the biotinylated, farnesylated tetrapeptide (59) using the Kaiser benzophenone oxime resin.

The convergent synthesis of a range of aryl ester dendrimers with peripheral tetrathiafulvalene units was also reported (Devonport et al. 1998). The dendrimers acquire some amount of the cation-radical tetrathiafulvalene tips on reacting with iodine in solutions. Another promising material is polyphenylene dendrimers functionalized with benzophenone units. On being transformed into the potassium ketyl derivatives, the dendrimers bring forth intermolecular biradicals. These technically attractive species contain four-membered cycles that coordinatively combine two potassium cations... 

Pridefine (80) is a somewhat structurally related antidepressant. It is a centrally active neurotransmitter blocking agent. It blocks norepinephrine in the hypothalamus but does not affect dopamine or 5-hydroxytryptamine. Its synthesis be-(jins by lithium amide-promoted condensation of diethyl succinate and benzophenone followed by saponification to 78. Heating in the presence of ethylamine gives N-ethylsuccinimide 79. Lithium aluminum hydride reduction completes the synthesis of pridefine (80)... 

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