Phenyl methylene ketone

Phenyl methylene ketone trimethylammonium bromide PhC(0)CHjNMe3Br 96.8 405.0 AOP 1997CHE/L1U... 

Phenyl methylene ketone dibutylsulfonium bromide PhC(0)CHjS(Bu)2Br- 94.9 397 AOP 1997CHE/LIU... 

In a detailed study of the reaction of methylene ketones with carboxylic acids in the presence of polyphosphoric acid, pyran-4-ones were obtained from l,3-diphenylpropan-2-one, phenylpropan-2-one and pentan-3-one (61JA193). In the first case, formation of 2,6-dimethylpyran-4-one ( 14 R = H) rather than the 2-benzyl-6-methyl-3-phenyl isomer... 

Chlorosulfides are often used for vicinal functionalization of alkenes. Silyl enol ethers can react with a-chloromethyl phenyl sulfides (5) in the presence of ZnBr2 or TiCU to give the corresponding -keto sulfide, which could be easily transfonned into the a-methylene ketone via sulfide oxidation to sulfoxide, followed by pyrolytic elimination (Scheme 23). 

Photolysis of (2-phenoxyphenyl)phenyldiazomethane (36) in cyclohexane at 10°C gave phenylcycloheptabenzofuran (37) via (2-phenoxyphenyl)phenylcarbene.The infrared spectrum of photo-chemically generated anthranylidene has been determined,and the dicarbene, (9,lO-dihydro-9,lO-o-benzeno-2,6-anthrylene)di(phenyl-methylene), has been shown by e.s.r. spectroscopy to have a quintet ground state.Products of photodecomposition 1,l-dimethyl-2-diazo-2-phenylethanol (38) in cyclohexane are the hydroxy ketone (39), the oxirane (40) and 3-phenylbutan-2-one (41), whereas reaction in methanol gave the methoxy alcohol (42) and the alkene (43).43... 

Coates et al. have extended this reaction to a method for gem-dialkylation at a methylene group adjacent to a carbonyl group. a-Phenyl thioketones can be alkylated at the carbon bearing sulfur, and the phenylthio group can be replaced by a second alkyl group by reduction-alkylation. For example, the ot-phenyl thio-ketone (1) is treated with sodium or potassium hydride in THF and then allowed... 

An iodine-catalyzed intramolecular oxidative thiolation of vinylic carbon-hydrogen bonds via tandem iodocyclization and dehydroiodination has also been developed for the construction of 2-methylene-3-thiophe-nones (14ASC743).The synthetic strategy was extended to the preparation of 2-methylene-3-benzothiophenone via the cyclization of o-methylthio-phenyl vinyl ketones. 

OJ4H44N4S N-Methyl-N -[bi8-(4-dimetlmlamino-phenyl)-methylen]-thioliamatoff 14, 95. Methyl-[p-(([Pg.1322]

Preparation by adding a solution of 30% hydrobro-mic acid in acetic acid to a solution of 4-(benzyloxy) -3-methoxy-phenyl cyclohexyl ketone in methylene chloride with stirring 2 h at r.t. (77%) [1084]. H NMR [1084], MS [1084]. 

The salts of some enamines crystallize as hydrates. In such cases it is possible that they are derived from either the tautomeric carbinolamine or the amino ketone forms. Amino ketone salts (93) ( = 5, 11) can serve as examples. The proton resonance spectra of 93 show that these salts exist in the open-chain forms in trifluoroacetic acid solution, rather than in the ring-closed forms (94, n = 5, 11). The spectrum of the 6-methylamino-l-phenylhexanone cation shows a multiplet at about 2.15 ppm for phenyl, a triplet for the N-methyl centered at 7.0 ppm and overlapped by signals for the methylene protons at about 8.2 ppm. The spectrum of 93 ( = 11) was similar. These assignments were confirmed by determination of the spectrum in deuterium oxide. Here the N-methyl group of 93 showed a sharp singlet at about 7.4 ppm since the splitting in —NDjMe was much reduced from that of the undeuterated compound. 

E)-2-Chlorovinyl phenyl ketone (1.83 g, 11 mmol) and triisopropyl phosphite (2.08 g, 10 mmol) were heated under an argon atmosphere for 1 h at 120 to 130°C. When all of the isopropyl chloride formed had distilled, the residue was chromatographed on a column of silica gel (18 g) being eluted with a 1 1 mixture of methylene chloride-ethyl acetate. The eluent was evaporated of solvent and the residue vacuum distilled to give pure diisopropyl (E)-2-benzoylvinylphosphonate (1.33 g, 45%). 

Diketones. Potassium enolates of some ketones can dimerize with incorporation of a methylene group from DMF to give 1,5-diketones. This novel reaction requires a rert-alkyl or phenyl group attached to the carbonyl group.2... 

Dibromoethane normally reacts with activated methylene groups to produce cyclopropyl derivatives [e.g. 25, 27], but not with 1,3-diphenylpropanone. Unlike the corresponding reaction of 1,3-dibromopropane with the ketone to form 2,6-diphenylcyclohexanone, 1,2-dibromoethane produces 2-benzylidene-3-phenyl-tetrahydrofuran and the isomeric 2-benzyl-3-phenyl-4,5-dihydrofuran via initial C-alkylation followed by ring closure onto the carbonyl oxygen atom (Scheme 6.2) [28],... 

Irradiation of iV-phenyl lactams affords cyclic products selectively rearranged to the ortho position. Studies on the influence of the chain legth on the regioselectivity of the PFR of several lactams have found that, even with 11 methylenes between the nitrogen atom and the carbonyl group, the coupling product was always the ortho ketone (Scheme 36) [95,96]. 

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