Diketonate derivatives

AEyl chloride reacts with sodamide in Hquid ammonia to produce benzene when sodamide is in excess, hexadiene dimer is the principal product, with some trimer and tetramer (C24, six double bonds). AEylation at carbon atoms alpha to polar groups is used in the preparation of a-aEyl-substituted ketones and nittiles. Preparation of P-diketone derivatives, methionic acid derivatives, and malonic ester, cyanoacetic ester, and P-keto-ester derivatives, etc, involving substitution on an alpha carbon between two polar carbonyl groups, is particularly facEe. 

Vinylogous amides, which have an enamine function in conjugation with a carbonyl group, constitute tridentate systems and thus open the possibility of alkylation on carbon, nitrogen, or oxygen. It has been found that the pyrrolidine enamine of acetylacetone gives rise to a carbon mcthylation but an oxygen ethylation product 41). The alkylation of cyclic 1,3-diketone-derived enamines has been studied 41,283). O Alkylation was found in alcohol solvents and predominant C alkylation in nonprotonic solvents. 

Amongst these are bis(cyclopentadienyl) and bis(y3-diketonate) derivatives, some of which are undergoing clinical trials, in the hope that they will provide more extensive application than cisplatin (pp. 1163-4). 

These transformations are analogous to those observed in the reaction of acety-lacetone with 1,3-diaminopropane (77ZC216) and formally fit decomposition of the corresponding /3-diketone derivatives. 

A number of recent papers have described the use of new types of /3-diketone derivatives to synthesize isoxazoles. We must first mention 1,1,3,3-tetraalkoxypropanes which are now manufactured on a large scale. Condensation of these derivatives with hydroxylamine has made readily available the parent compound, unsubstituted isoxazole itself (4). " This type of reaction using tetraalkoxypropane... 

A particular case of the synthesis of isoxazoles via -diketone derivatives is the preparation of 3-halogenoisoxazoles (11) from -nitroketones (9) treated with hydrogen halides. This inter-... 

Fused 1,4-dithiins are formed when the 1,8-diketones derived from dithiols and a-bromoketones are treated with Lawesson s reagent (LR) <96TL2821>. 

Silver(I) /3-diketonate derivatives have received significant attention due to the ease with which they can be converted to the elemental metal by thermal decomposition techniques such as metal organic chemical vapor deposition (MOCVD).59 The larger cationic radius of silver(I) with respect to copper(I) has caused problems in achieving both good volatility and adequate stability of silver(I) complexes for the use in CVD apparatus. These problems have been overcome with the new techniques such as super critical fluid transport CVD (SFTCVD), aerosol-assisted CVD (AACVD), and spray pyrolysis, where the requirements for volatile precursors are less stringent. 

The synthesis of the pyridine ring from ethyl acetoacetate, aldehydes, and ammonia proceeds extraordinarily readily. The mechanism is as follows. In the first phase the aldehydes react with the acetoacetic ester to form alkylidene bis-acetoacetic esters. The 1 5-diketone derivatives so formed undergo ring closure by introduction of a molecule of ammonia and elimination of two molecules of water ... 

An enantioselective approach to both enantiomers of a-alkyl-a-methoxyarylacetic acid derivatives has been described from L-(- -)-tartaric acid. Key steps include stereoselective addition of Grignard reagents to 1,4-diketones derived from tartaric acid. This methodology has been applied in synthesizing the pine beetle pheromone frontalin. 

In a very interesting paper, Rtiedi and colleagues have presented a convenient a-oximation method that allows for the selective preparation of 1,2-dione monoximes 38a, 40a, 41a and/or their hydrolyzed 1,2-diketone derivatives 38b, 40b, 41b simply by using the appropriate amount of the in situ generated nitrosyl chloride and ketones 37 or 39 (Scheme 26 route a or b). 

Oxidation of 2,3-epoxynorbomane to diol, ketohydroxy, and diketone derivatives was studied with RuCyaq. oxidant/CCl -CHjCN (co-oxidant=(I04) , H O, Oxone , (CIO)", (S Og) " (BrO )" was ineffectual) [73]. The system RuClj/aq. Na(10 )/CCl4-CH3CN oxidised substituted epoxides containing bicyclic [2.2.1] heptane skeletons, e.g. exo-2,3-epoxynorbomanes to the corresponding diketo compounds [74]. Stoicheiometric RuOyCCl converted 20,21-dihydroxy-lip,... 

A series of 1,3-diketones derived from the benzoyl derivatives of 8-acetyl-9-hydroxy-naphtho[2, l-6]pyran-3-one (437) and similar compounds have been cyclized to the pyran-4-one (438 Scheme 150) (80MI22402). 

Rearrangement of diketonate derivatives of trivalent Co, Rh, Cr and Ru are sufficiently slow that kinetic parameters for isomerization or racemization may be obtained after chromatographic... 

Both imprinted polymers showed an enhancement in the catalytic activity that was about 50-fold higher than the control polymer (P0) and turnover of the catalytic cavities was also demonstrated. However, when comparison was made with a polymer containing Co(II) but which was not imprinted with the template (PI), the rate acceleration dropped to about fourfold. In addition, the control of the enantioselectivity of the reaction was very low. In fact, the polymer, imprinted with the diketone derived from the / -camphor, was able to catalyse the reaction, between the 5-camphor and benzaldehyde, with an acceleration rate almost identical to that obtained with the polymer imprinted with the opposite enantiomer. The rate enhancement between the two polymers was in fact equal to 1.04. 

From the first synthesis of rare-earth /9-diketonates in 1897 by Urbain until now, hundreds of different complexes formed by reaction between Lnni ions and /3-diketone derivatives have been described in the literature. Interest for this type of complexes comes from then-potential application in numerous and diverse domains. These complexes can be used for example as extractants in solvent-solvent extraction processes or as active compounds for the development of chelate lasers or liquid lasers. But they can also find applications in NMR as shift reagents or as electroluminescent materials in organic light-emitting diodes (OLEDs) (Binnemans, 2005b). 

A procedure for the preparation of 1,2-diketone derivatives has been devised whereby the hydrazone of an a-chloroketone is converted into the corresponding azide. Further oxidation with trifluoroacetic acid yields the diketone product209. 

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