1,3 -Diketones reactions

More recent work in this series demonstrated that a carbonyl group can be interposed between the side-chaincarrying aromatic ring and the ethylene function with full retention of activity. Claisen condensation of benzoate with 2-tetralone affords the e-diketone Reaction of... 

Diimines of a-diketones—reaction of aromatic aldimines with sodium cyanide in DMSO at 20°C (72 hr) [57]. 

In a typical /J-diketone reaction, nitromalonaldehyde reacts with hydroxyl-amine to produce the parent 4-nitroisoxazole,39-58 Similarly, dibenzoyl-nitromethane yields 3,5-diphenyl-4-nitroisoxazole 64.5 7... 

Diketones. Reaction of the silyloxycyclopropane 1 with Cu(BF4), (0.5 equiv., ether, 15°) affords the 1,6-diketone 2 as a mixture of racemic and meso-isomers in 80% isolated yield. A p-copper ketone (a) is postulated as intermediate. The same reaction... 

Oxidation of a-hydroxyketones wifh lead tetraacetate gives a-diketones reaction in the presence of water or alcohol affords the formyl carboxylic acid or its ester (Scheme 13.56) [75]. 

The sulfide polymers covered in this chapter are those based on the polysulfides derived from the reaction of dihalides and sodium di- or polysulfides polyphenylene sulfides generated from aryl dihalides and sodium sulfide polyalkylene sulfides generated from ethylene episulfide or dimercaptan-olefin or diolefin-diketone reactions, all of which are outlined in Scheme 1. 

Metal beta-diketonate reactions on alumina heat-treated at 600 °C [41]. See... 

Metal beta-Diketonate Reaction temperature (°C) Metal atoms/nm2 Carbon atoms/nm Ligand /metal ratio... 

Other groups than amines have been used, such as crosslinked polymers and rubbers containing acetylacetonate groups with metal ions. Ito and Saegusa prepared chelating polystyrenes containing 22- and 2 membered macrocyclic-l,3-diketones (reaction 13). 

This reaction applies to many i,2 diketones, and is termed the Benzilic Acid Rearrangement. It provides a ready method for the preparation of disubstituted a4iydroxy-carboxylic acids. When applied to a cyclic 1,2-diketone, the ring system is necessarily reduced by one carbon atom for example, cyclohexan-i,2 ... 

This reaction consists of the condensation of two molecular equivalents of a 1,3 diketone (or a J3-keto-ester) with one equivalent of an aldehyde and one of ammonia. Thus the interaction of ethyl acetoacetate and acetaldehyde and ammonia affords the 1,4-dihy dro-pyridine derivative (1), which when boiled with dilute nitric acid readily undergoes dehydrogenation and aromatisation" to gb e the diethyl ester of collidine (or 2,4,6-trimethyl-pyridine-3,5 dicarboxylic acid (II)). For the initial condensation the solid aldehyde-ammonia can conveniently be used in place of the separate reagents. 

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