Butanedione 2-methyl-1 -phenyl

This procedure represents a novel, convenient, and fairly general method for preparing y-aryl-/3-diketones. By this method the submitters have phenylated the dianion of 1-phenyl-1,3-butanedione (61%), 2,4-heptanedione (98%), 2,4-nonanedione (78%), 2,4-tridecanedione (53%), and 3,5-heptanedione (50%).6 Substituted diaryliodonium salts have also been used to produce l-(4-chlorophenyl)-2,4-pentadione (44%), 4-(4-methyl-phenyl)-l-phenyl-l,3-butanedione (44%), and l-(4-methyl-phenyl)-2,4-nonanedione (21%).6 Under these conditions no more than a trace, if any, of arylation at the a-position of the /3-diketones was observed by gas chromatography analysis. 

This regioselectivity is practically not influenced by the nature of subsituent R. 3,5-Disubstituted isoxazolines are the sole or main products in [3 + 2] cycloaddition reactions of nitrile oxides with various monosubstituted ethylenes such as allylbenzene (99), methyl acrylate (105), acrylonitrile (105, 168), vinyl acetate (168) and diethyl vinylphosphonate (169). This is also the case for phenyl vinyl selenide (170), though subsequent oxidation—elimination leads to 3-substituted isoxazoles in a one-pot, two-step transformation. 1,1-Disubstituted ethylenes such as 2-methylene-1 -phenyl-1,3-butanedione, 2-methylene-1,3-diphenyl- 1,3-propa-nedione, 2-methylene-3-oxo-3-phenylpropanoates (171), 2-methylene-1,3-dichlo-ropropane, 2-methylenepropane-l,3-diol (172) and l,l-bis(diethoxyphosphoryl) ethylene (173) give the corresponding 3-R-5,5-disubstituted 4,5-dihydrooxazoles. 

Tamariz et al. reported the synthesis of mukonine (11) based on a regioselective Diels-Alder reaction of N-phenyl-4,5-dimethylidene-2-oxazolidinone (634) with methyl propiolate (635). The diene 634 was prepared in moderate yield from the condensation reaction of 2,3-butanedione (632) with phenyl isocyanate (633). In an optimized reaction procedure using drastic basic hydrolytic conditions (KOH/ MeOH), followed by methylation with dimethyl sulfate, the adduct 636, was... 

The cycloaddition reactions of the unsymmetrical a-diazo-/3-diketone, 2-diazo-l-phenyl-l,3-butanedione 330, with diaryl imines 331 took place with high regioselectivity, affording exclusively the 6-methyl-5-phenyl-substituted 477-l,3-oxazin-4-ones 332 via the acetylphenylketene, generated by the thermal Wolff rearrangement of 330 (Equation 32) <2002HAC165>. 

C10H9NO4 methyl trans-3-(4-nitrophenyl)-2-propenoate 637-57-0 25.00 1.3140 2 19125 C10H10O2 1-phenyl-1,3-butanedione 93-91-4 74.00 1.0599 1... 

Preparation of 52 [50] A solution of polymer-supported morpholine 47 (170 mg), l-phenyl-l,3-butanedione 50 (0.5 mmol), and (4-carboxyphenyl)hy-drazine hydrochloride (0.6 mmol) in methanol was shaken for 2.5 h. The methanol was then removed under a stream of nitrogen, dichloromethane (4 mL) and polymer-supported isocyanate 48 (350 mg) were added, and the reaction mixture was shaken for a further 16 h. An additional portion of polymer-supported isocyanate 48 (120 mg) was then added. After 4h, the resin was filtered off and washed with dichloromethane (2 x 1.5 mL). The combined organic phases were concentrated in vacuo to give the desired product, 4-(3-methyl-5-phenylpyrazol-l-yl)benzoic acid 51. 20 mg (70 umol) of this benzoic acid was dissolved in dichloromethane and the solution was treated with polymer-supported morpholine 47 (100 mg) and 0.1 m isobutyl chloroformate in dichloromethane (0.75 mL, 75 pmol). The resulting slurry was shaken under nitrogen at rt for 30 min and then treated with a solution of (3-isopropoxypropyl)amine (100 mg, 85 pmol) in dichloromethane... 

Methylbenzoylacetone (2-methyl-1-phenyl-1,3-butanedione) 400 401 The calculated amount of sodium wire is added to benzoylacetone dissolved in six times its amount of anhydrous ether. This precipitates the sodio derivative as a sulfur-yellow powder. For further reaction402 a portion (3 g) of this derivative is dried over phosphoric oxide and heated for 4 h under reflux with methyl iodide (1.9 g) in anhydrous acetone (50 ml). The acetone is then distilled off and the residue is taken up in ether, shaken with water, dried, and fractionated, giving 88% of the product, b.p. 130-134°/11 mm. 

Weygand and Koch37 isolated a pure enolic form of 2-methyl-l-phenyl-1,3-butanedione as follows ... 

The oily 3-methyl-l-phenyl-1,3-butanedione(l g) is added to a solution of sodium (0.15 g) in methanol (3 ml), and the deep yellow solution is at once filtered and dropped into 5n-sulfuric acid (30 ml) cooled in ice-salt. The emulsion that is thus first formed must be whipped vigorously with a glass rod to cause solidification, so that most of the material becomes finely powdered and readily filterable if the oil globules once become large the product does not crystallize well and is unstable. The solid precipitate is at once filtered off, washed with very dilute hydrochloric acid, followed by ice-cold ethanol and then light petroleum, and is finally recrystallized from low-boiling light petroleum in a quartz vessel. The m.p. is 51° and the yield almost quantitative. 

The two possible products can be distinguished by an iodoform test. A haloform reaction is the base-catalyzed substitution of all three methyl-hydrogens by three halogens, Since 2-methyl-l-phenyl-l,3-butanedione contains an acetyl methyl group, it will readily undergo an iodoform reaction, while 1-phenyl-l,3-pentanedione will not. 

Butanedione bis[4-(4-chloro-3-(trifluoromethyl)phenyl) thiosemicarbazone], B-00591 3-Butanedione bis[4-(3,4-dichloropheny 1) thiosemicarbazone], B-00592 3-Butanedione bis[(2-fluorophenyl) thiosemicarbazone], B-00593 3-Butanedione bis[(4-fluorophenyl) thiosemicarbazone], B-00594 3-Butanedione bis[[4-(6-methyl-2-benzothiazolyOphenyl] thiosemicarbazone], B-00595 3-Butanedione bis[(4-nitrophenyl) thiosemicarbazone], B-00596 3-Butanedione... 

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