P-Chloroacetophenone

The presence of unsaturation in the side chain is also compatible with antihistaminic activity. Mannich condensation of p-chloroacetophenone with formaldehyde and pyrollidine affords the amino ketone, 109. Reaction with an organometallic reagent from 2-bromopyridine gives 110. Dehydration leads to triproli-dine (111). ... 

While looking for the optimum operating conditions of the effect of dimethylamine on p-chloroacetophenone, the technicians heated the medium at 234°C the reagents proportion in weight being 1/4.22. The medium detonated not long after. It is likely that this was an aromatic nucleophilic substitution reaction as follows ... 

Recently, Suzuki-type reactions in air and water have also been studied, first by Li and co-workers.117 They found that the Suzuki reaction proceeded smoothly in water under an atmosphere of air with either Pd(OAc)2 or Pd/C as catalyst (Eq. 6.36). Interestingly, the presence of phosphine ligands prevented the reaction. Subsequently, Suzuki-type reactions in air and water have been investigated under a variety of systems. These include the use of oxime-derived palladacycles118 and tuned catalysts (TunaCat).119 A preformed oxime-carbapalladacycle complex covalently anchored onto mercaptopropyl-modified silica is highly active (>99%) for the Suzuki reaction of p-chloroacetophenone and phenylboronic acid in water no leaching occurs and the same catalyst sample can be reused eight times without decreased activity.120... 

Kinetic studies performed on model compounds were aimed at understanding the effect of different parameters on the selectivity. They showed that selectivity was achieved only when A336 was present. In fact, in the absence of A336 and of the base the hydrodehalogenation of p-chloroacetophenone proceeded aU the way to ethylcyclohexane in the biphasic aqueous-organic system. When A336 was added, selectivity was reversed—chloride was removed first—and the selective dehalogenated benzyl alcohol was obtained. ... 

A. (o-Bromo-p-chloroacetophenone oxime. A 500-mL, four-necked, round-bottomed flask equipped with a dropping funnel (closed with a giass stopper), mechanicai stirrer, drying tube (calcium chioride, CaCij), and a thermometer is charged with p-chloroacetophenone (38.6 g, 0.25 moi), glacial acetic add (220 mL) and aqueous hydrobromic acid (HBr) [1 mL, 48 % (w/w). Note 1]. The flask is immersed in a water bath (15°C, Note 2) and bromine (40.0 g, 0.25 mol) is added from the dropping funnei at such a... 

A three-necked, round-bottomed flask with Claisen head may be used instead. p-Chloroacetophenone (97%), hydroxylamine hydrochloride (purum p.a. >98%), potassium 0-ethyl xanthogenate (>98%), bromine (puriss. p.a., >99.5%), and hydrobromic add [puriss. 48% (w/w)] were obtained from Ruka Chemika and used as... 

Drying lo-bromo-p-chloroacetophenone oxime was carried out in the dark since otherwise this material turns pink in light. Wrapping the flask with )luminum foil provides adequate light protection for this purpose. 

Rather phase-insensitive Norrish II photoproduct ratios are reported from irradiation of p-chloroacetophenones with a-cyclobutyl, a-cyclopentyl, a-cycloheptyl, a-cyclooctyl, and a-norbonyl groups [282], In each case, the E/C and cyclobutanol photoproduct ratios are nearly the same in neat crystals as measured in benzene or acetonitrile solutions. On this basis, we conclude that the reaction cavity plays a passive role in directing the shape changes of these hydroxy-1,4-biradicals. As long as the initial ketone conformation within the cavity permits -/-hydrogen abstraction (and these ketones may be able to explore many conformations even within their triplet excited state lifetime), the cavity free volume and flexibility allow intramolecular constraints to mandate product yields. 

Examples of this extreme stereoselectivity and specificity have been found by Scheffer and Trotter in crystals of a-adamantyl p-chloroacetophenone (86b), also [282], Figure 49 shows ORTEP-like drawings of the conformations in the dimorph plate and dimorph needle crystals of 86b as obtained upon recrystallization from different solvents. A major difference between the two is the cant of the aryl ring (and the carbonyl group) with respect to the adamantyl moiety. 

The following couples were tested p-chlorobenzonitrile/p-chloro-acetophenone, p-chloroacetophenone/p-chlorodiphenyl, p-chlorodiphenyl /chlorobenzene, p-chlorodiphenyl/p-chlorofluorobenzene, chlorobenzene /p-chlorotoluene, chlorobenzene/p-chloroanisole, p-chloroacetophenone/ methyl ester of m-chlorobenzoic acid, chlorobenzene/m-chlorotoluene, p-chlorodiphenylether/p-chlorotoluene, m-chlorodiphenylether/chloroben-zene, m-chlorodiphenylether/p-chlorotoluene, chlorobenzene/methyl ester of m-chlorobenzoic acid, chlorobenzene/p-bromoanisole, p-bromoaceto-phenone / p-chlorobenzonitrile, p-bromobenzonitrile / p-chloroacetophe-none, bromobenzene/p-chlorodiphenyl, m-bromotoluene/chlorobenzene, and p-chlorodiphenyl/p-bromotoluene. 

Acetophenone Dichloroselenoaceto- phenone Dichloroseleno-p- chloroacetophenone (CeHg.CO.CH SeCla 121 5 77 1-2 days. 

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