Preparation of α,β-Unsaturated Ketones Bearing a Trifluoromethyl Group and Their Application in Organic Synthesis

Abstract

Abstract:The approaches to the synthesis of α,β-unsaturated CF 3 -containing ketones and their use in organic chemistry are reviewed. The synthetic applications of these ketones are discussed. The formation of 4-, 5-, 6-and 7-membered heterocycles bearing a CF 3 group based on reactions of α,β-unsaturated CF 3 -containing ketones with different nucleophiles are discussed.

Kinetic Spectrophotometric Determination of Propellant Grade Hydrazines using Thiophenes with Active Carbonyl Groups

“…3). Similar nucleophilicity of the two nucleophilic centers of Hydrazine was cited by Nenajdenko 15 , et al as the reason behind the possibility of attack of the nucleophile at both the double bond and the carbonyl group. Due to methyl group substitution of MMH, two regioisomers of pyrazoline were expected to be formed UV-Vis study of this interaction in acetonitrile medium (Fig.…”

“…4) showed that there is a decrease in absorbance for the peak at 320 nm which is followed by the formation of new peak at lower wavelength (232 nm). Decrease in absorbance for the peak at 320 nm is indicative of involvement of double bond and carbonyl group in the reaction leading to disturbance of the conjugation in the side chain of thiophene moiety and hence pyrazoline formation 11,15 . Due to hydrazine interaction, wave length at 229 nm is shifted to higher wavelength (232 nm).…”

“…This intermediate is transformed into pyrazoline (with C=N bond) by spontaneous elimination of water molecule as shown in the scheme 2. Hence, transformation 15 of pyrazolidine to pyrazoline might…”

Succinic acid dihydrazide: a convenient N,N-double block for the synthesis of symmetrical and non-symmetrical succinyl-bis[5-trifluoro(chloro)methyl-1H-pyrazoles]

“…Since the 1970s, according to previous publications, [20][21][22][23] research groups have reported the systematic synthesis of 4-substituted 4-alkoxy-1,1,1-trihaloalk-3-en-2-ones (1) from the trihaloacetylation reaction of the respective enolethers (1a, 1b) or acetals (1c-i) with trifluoracetic anhydride or trichloroacetyl chloride, respectively.…”

“…Thus, 4-alkoxy-4-(alkyl/aryl/heteroaryl)-1,1,1-trifluoro(chloro)alk-3-en-2-ones are versatile precursors for the heterocyclic synthesis and direct construction of this type of heterocycles. [20][21][22][23] In this context and in an attempt to develop synthetic methods to obtain acyl spacer heterocycles and new fluorinated molecules, herein we report a practical and regioselective methodology for the preparation of a series of 1,4-bis …”