1.3- Diphenyl-l ,3-propanedione

Polarographic studies on the reduction of 1,3-diphenyl-l, 3-propanedione in 50 % ethanol-water at the mercury cathode in the pH range 4.2 - 13.6 show that this compound is reduced in three successive steps, two one-electron transfers and a two-electron transfer at the most negative potential133 Cpe at either of the two first waves produces pinacolic products, whereas cpe at the third wave produced a good yield of the diol as a meso-dl mixture (Eq. (71) ). 

Eleven and two-tenths grams (0.05 mol) of 1,3-diphenyl-1,3-propanedione is ground in a mortar with 5.84 g. (0.017 mol) of tris(2,4-pentanedionato)chromium(III) until a fine homogeneous powder is obtained. The mixture is transferred to an Erlenmeyer flask equipped with a gas inlet tube. The flask is heated slowly in an oil bath or with a heating mantle, in a hood, with a slow stream of nitrogen (about 0.5 l./minute) flowing over the mixture. The mixture melts at about 75° at about 150°, 2,4-pentanedione is... 

C23H2iCl202Rh, 1,3-Diphenyl-1,3-propanedione-(1,6-dichloro-1,5-cyc-looctadiene)rhodium(l), 40B, 796... 

Mamedov VA, Polushina VL, Mertsalova EF, Nuretdinov lA, Plyamovatyi AKh (1991) Medium effect on the direction of the reaction of 3-chloro-l,3-diphenyl-1,2-propanedione with ortho-phenylenediamine. Bull Rus Acad Sci Div Chem Sci 40(7) 1472-1474. doi 10.1007/ BF00961256... 

The plasma half-life of cathinone is 1.5 hours. The primary metabolites are norpseudoephedrine, norephedrine, 3,6-dimethyl-2,5-diphenyl-pyrazine, and l-phenyl-l,2-propanedione (Szendrei 1980 Brenneisen etal. 1986 Guantai and Maitai 1983). However, norpseudoephedrine and norephedrine also originate directly from the leaves, as well as being metabolic products (Widler et al. 1994). Maximal plasma concentrations of norephedrine and norpseudoephedrine are reached at about 3.3 and 3.1 hours, respectively. These two drugs have a much longer duration of action than cathinone, where terminal half-lives could not be calculated after 10 hours. 

The desymmetrization of 2-alkyl-1,3-diketones to the corresponding chiral hydroxyketones was also successfully achieved with the same catalyst system. For example, 2-methyl-l,3-diphenyl-l,3-propanedione was reduced with an equimolar amount of NaBH4 together with THFA and ethanol in the presence of 0.05 equivalents of (R,R)-15 to afford (lk,2S)-2-methyl-3-oxo-1,3-diphenyl-propane (anti syn=99 l) in 99% ee (Scheme 10) [55], 2-Allyl- and 2-benzyl-sub-... 

SYNS OMEGA-BENZOYLACETOPHENONE 2-BENZOYLACETOPHENONE DIBENZOYLMETHANE l,3-DIPHENYL-l,3-PROPANEDIONE KARENZU DK2 1,3-PROPANEDIONE, 1,3-DIPHENYL- RHODIASTAB 83... 

PyrazoUne-5-ones. Treatment of 2-bromo-l,3-diphenyl-l,3-propanedione (1) with methylhydrazine in ethanol at room temperature gives l-methyl-3,4-diphenyl-A -pyrazoline-5-one (2) in 56% yield. It is probably formed by a halohydrin rearrangement as indicated. 

In 1967 Evans and Woodbury reported a thorough electrochemical investigation of l,3-diphenyl-l,3-propanedione in ethanol-water mixtures at a wide range of pH. Their polarographic and coulometric results imply formation of three different reduction products with the consumption of one, two and four electrons, respectively. A two-electron reduction of the substrate at pH = 7 leads possibly either to a 1,2-dihydroxycyclopropane (9a) or to 1,2,4,5-tetrahydroxycyclohexane derivative (9b) but the actual structure could not be determined absolutely due to difficulties in obtaining a pure product. 

The reaction between l,3-diphenyl-2-(phenylmethylene)-l,3-propanedione (85a) and ylides (86) has been shown to result in the formation of Michael adducts (87). In contrast, under identical conditions 1,3-diphenyl-2-(phenyl-imino)-l,3-propanedione (85b) undergoes Wittig olefination yielding alkenes (88). ... 

Arbuzov, B.A., Polozov, A.M., and Polezhaeva, N.A., Catalytic and thermal decomposition of 2-diazo-l,3-diphenyl-l,3-propanedione in dimethyl hydrogen phosphite and O,O-diethyl hydi ogen phospho-rothioite, Zh. Obshch. Khim., 54, 1517, 1984 J. Gen. Chem. USSR (Engl. Transl.), 54, 1351. 1984. Arbuzov, B.A., Polozov, A.M., and Polezhaeva, N.A., P-H addition of carbenoids and carbenes as a method for the synthesis of 2-phospho-substituted 1,3-dicarbonyl compounds, Dokl. Akad. Nauk SSSR, Ser. Khim., 287, 849, 1986 Dokl. Chem. (Engl. Transl.), 287, 69, 1986. 

The universal synthetic method used to prepare an Ir(C N)2(LX)-type complex is shown in Fig. 5. Dimer complex [Ir(C N)2Cl]2 is readily prepared from reaction of the ligand precursor and IrCl3-nH20 [79], and chloro-ion ligands can be subsequently replaced with an LX chelate. The most studied ancillary ligand LX is acac, but it can be varied with other monoanionic bidentate ligands, such as picolinic acid, N-methylsalicylimine [23], 2-(5-phenyl-4//-[l,2,4]triazol-3-yl)-pyr-idine [28], 2,2,6,6-tetramethyl-3,5-heptanedionate, 1-phenyl-4,4-dimethyl-1,3-pen-tanedionate, l,3-diphenyl-l,3-propanedionate, pyrazolyl, pyrazolyl-borate [80], and (2-pyridyl) pyrazolate derivatives [81]. 

---