Trifluoromethyl acetylacetonate

Reaction type 3 (equation 10), where the complete hetero-l,3-diene skeleton is incorporated into the newly formed ring system, occurs with compounds having both a nucleophilic center and an electrophilic center If these two functionalities are in positions 1 and 2, various types of six-membered ring systems become accessible 4,4-Bis(trifluoromethyl)-I,3-diaza-1,3-butadienes require only room temperature to react with acetyl cyanide to yield l,4,5,6-tetrahydropynmidin-6-ones [96] Likewise, certain open-chain 1,3-diketones (acetylacetone and acetoacetates) and the heterodiene form six-membered nng systems [97] (equation 19)... 

Thenoyltrifluoroacetone(TTA), C4H3S,CO,CH2,COCF3. This is a crystalline solid, m.p. 43 °C it is, of course, a /1-diketone, and the trifluoromethyl group increases the acidity of the enol form so that extractions at low pH values are feasible. The reactivity of TTA is similar to that of acetylacetone it is generally used as a 0.1-0.5 M solution in benzene or toluene. The difference in extraction behaviour of hafnium and zirconium, and also among lanthanides and actinides, is especially noteworthy. 

Selenophene /3-diketones can be used as extractants for the separation and isolation of metals. The advantages of selenophene /3-dike-tones were revealed by comparison of their dissociation and distribution constants with those of acetylacetone, benzoylacetone, thenoyl-trifluoromethylacetone, etc. Selenophene /3-diketones containing a trifluoromethyl group and a pyridyl radical were of particular interest. 2-Acetoacetylselenophene127 is better for the extraction of thorium from water than acetylacetone, previously extensively used. 

Acetylacetone and alkyl acetoacetates, both (1,3 nn) species, and per-fluorobut-2-ene, a masked (1,2 ee) compound, react in the presence of sodium hydride at room temperature to give 2,3-bis(trifluoromethyl)furans [83JCS(P1)1239] (Scheme 27). 

It is interesting to note that rZr(acac)3Cl] can be recrystallized unchanged from hot acetylacetone. An NMR study has shown that substitution of the chlorine atom is very slow under anhydrous conditions heating [Zr(acac)3Cl] with neat acetylacetone for 24h at 80 °C yields a product which is only 20% [Zr(acac)4]. In the presence of water, [Zr(acac)3Cl] is readily converted to [Zr(acac)4], - evidently due to preliminary hydrolysis of the Zr—Q bond. In anhydrous media, the ease of complete substitution is dependent on the nature of the diketone certain aryl- and trifluoromethyl-substituted diketones readily react with ZrCU to give the tetrakis(diketonates). 

The inoeased ability of polyfluorinated compounds to undergo fluorine substitution was used for the synthesis of trifluoromethyl-substituted furans. Reaction of perfluorobut-2-ene 131 with acetylacetone or acetoacetic ester furnished 2,3-bis(trifluoromethyl)furans 132 through two sequential fluorine substitutions [97]. Similarly, fluoride-ion catalyzed reaction of fluorinated enol phosphates 133 led to dihydrofurans 134 which treatment with a base produced furans 135 in 44-56 % yields [98]. 

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