Camphorquinone

When camphor (I) is heated with selenium dioxide in acetic acid, the methylene group next to the carbonyl group is oxidised also to a carbonyl group, to form camphorquinone (II). Note that the compound (II) is not a true quinone but a 1,2-diketone ... 

Then cool the reaction-mixture, filter it at the pump, leaving a black residue of selenium, and wash out the flask twice with 2x5 ml. of acetic acid, passing the washings also through the filter. Dilute the united filtrates with water, and make the solution alkaline with 10% aqueous sodium hydroxide, which precipitates the camphorquinone. Cool, filter off the yellow camphorquinone at the pump, wash with water and drain thoroughly. 

The camphorquinone can be purified in either of two ways, (i) To save time, the drained but still damp material can be recrystallised from water containing 10% of acetic acid, the hot filtered solution being cooled and vigorously stirred. The quinone separates as brilliant yellow crystals (yield, 2 5 g.), m.p. 192-194 , increased to 196-197 by a second reciystal-lisation. (ii) The crude camphorquinone can be dried in a vacuum desiccator (weight of dry quinone, 5 g.), and then recrystallised from petroleum (b.p. 100-120 ), the hot solution being filtered through a fluted paper in a pre-heated funnel. The quinone separates in beautiful crystals, m.p. 196-197 , 2 8 g. 

Kampher-baum, m. camphor tree, -chinon, n. camphorquinone. -essig, m. camphorated vinegar, -geist, m. spirit of camphor. 

PdCl2(camphorquinone dioxime)2,5, 1119 PdC20H32Cl2P 4 [PdCl2(diphos)2]2+. 5,1124 PdC21H17N2PS3... 

In chemically-cured materials, one example of an initiator/activator system is hydrogen peroxide as initiator, ascorbic acid as activator and cupric sulphate as co-activator. In light-cured materials, camphorquinone is used as a visible-light photochemical initiator, sodium p-toluene-sulphinate as activator and ethyl 4-dimethylaminobenzoate as photoaccelerator. 

When camphorquinone, which is known to scavenge all free ketyl radicals by hydrogen transfer,<74,76> was added to the photolysis mixture only the mixed pinacol and benzhydrol were produced, in the ratio of 1 to 0.8, respectively ... 

Since the mixed pinacol is formed in the presence of the ketyl radical scavenger camphorquinone, its formation must occur under conditions where the ketyl radicals are not available for scavenging, that is, in a solvent cage. Since benzpinacol is not observed under these conditions, its formation must occur outside of the initial solvent cage. The following mechanism is proposed ... 

In 1974, Nakamura and Otsuka reported enantioselective cyclopropanation of terminal olefins, using bis[(l)-camphorquinone-o -dioximato]cobalt(II) complex (96) as the catalyst. Although dia-stereoselectivity was modest, good enantioselectivity was attained (Scheme 69).263-265 Cyclopropanation using CoII(salen) as the catalyst was also examined, but the enantioselectivity was low.265... 

The SSZ-33 zeolite was synthesized using the template molecule derived from 8-keto tricycle [5.2.1.0] decane. The boron containing SSZ-33 was converted to Al-SSZ-33 by a one-step reflux in 1 M aluminum nitrate. The SSZ-35 zeolite was prepared with the template camphorquinone. SSZ-35 zeolite was then subjected to three-fold ion exchange in ammonium nitrate. 

Di-biphenylene-ethylene d - Nitronaphthalene Diphenylketene Camphorquinone Violuric Acid Veronal... 

Figure 2 The rate of polymerization of MSA as a function of time initiated with (a) 1.0 wt% DMPA and 60 mW/cm ultraviolet light, (b) 0.05 wt% DMPA and 60 mW/cm ultraviolet light, and (c) 1.0 wt% camphorquinone, 1.0 wt% triethanolamine and 25 mW/cm visible light.

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