3-Phenyl-2, 4-pentanedione

Silver fluoborate, reaction with ethyl bromide in ether, 46, 114 Silver nitrate, complexing with phenyl-acetylene, 46, 40 Silver oxide, 46, 83 Silver thiocyanate, 45, 71 Sodium amide, in alkylation of ethyl phenylacetate w ith (2-bromo-ethyl)benzene, 47, 72 in condensation of 2,4-pentanedione and 1 bromobutane to give 2,4-nonanedione, 47, 92 Sodium 2 ammobenzenesulfinate, from reduction of 2 mtrobenzenesul-finic acid, 47, 5... 

Trimethyl phosphite (11.3 g, 0.091 mol) was added to a solution of 3-benzylidene-2,4-pentanedione (16.35 g, 0.091 mol) in dry methylene chloride. The solution was maintained under nitrogen for 24 h at 20°C and for an additional 5 h at 40°C. After this time, the solvent was evaporated, and the residue was dissolved in hexane. These actions were performed in the absence of moisture. The clear hexane solution was seeded with a crystal of the pure crystalline product (obtained by crystallization from hexane by standing for 2 weeks at 0°C), and after 8 h at 0°C the crystals precipitated yielding pure 2,2,2-tri-methoxy-3-phenyl-4-acetyl-5-methyl-A4-oxaphospholene (25.12 g, 88.4%) of mp 48-51°C. 

IODONIUM CHLORIDE 1-PHENYL-2, 4-PENTANEDIONE, 51, 128 4-Phenyl-l-carbethoxysemicar-bazide, from ethyl hydra-zinecarboxylate and phenyl isocyanate, 51, 122 with potassium hydroxide to give 4-phenylurazole, 51,... 

Pentanedione, with sodium amide and diphenyliodonium chloride to give 1-phenyl-... 

Sodium, with l-bromo-3-chloro-cyclobutane to give bicyclo [l.l.O]butane, 51, 55 Sodium amalgam, 50, 50, 51 Sodium amide, with 2,4-pentane-dione and diphenyliodonium chloride to give l-phenyl-2, 4-pentanedione, 51, 128 Sodium azide, 50, 107 with mixed carboxylic-carbonic anhydrides, 51, 49 Sodium borohydride, reduction of erythro-3-methanesulfony-loxy-2-butyl cyclobutanecar-boxylate, 51, 12 reduction of 2-(1-phenylcyclo-pentyl)-4,4,6-trimethyl-5,6-dihydro-1,3(4H)-oxazine to 2-(1-phenylcyclopentyl)-4,4, 6-trimethyltetrahydro-l,3-oxazine, 51, 25 Sodium cyanoborohydride, used... 

N- (3 or 4) - [[4- (Hydroxymethyl) phenoxy] -tert-butyl-phenylsilyl]phenyl pentanedionic acid monoamide Polyethylene glycol Pivaloyl... 

Diphenyliodonium chloride, with 2,4-pentanedione and sodium amide to give 1-phenyl-2,4-pentanedione, 51,128... 

Diketones cyclize much more efficiently than simple ketones. Photochemical cyclobutanol formation is the key step in a novel route14 to 1,3-cyclopentanediones, as exemplified by the conversion of l-bromo-5-phenyl-2,3-pentanedione to 4-phenyl-l,3-cyclopentanedione. 

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