A Convenient Synthetic Method for β-Alkoxy- and β-Phenoxyacrylic Acids and 3,4-Dihydro-2H-pyran-5- and 2,3-Dihydrofuran-4-carboxylic Acids

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

“…Trifluoroacetylation of ketene dithioacetals [16], vinyl sulfides [16], vinyl amides [17], vinyl ethers [17,18] (including cyclic vinyl ethers [18,19]), enamines [20,21] proceeds at room temperature to give the corresponding β-trifluoroacetylated compounds in high yields (Scheme 2). Activated dienes, e.g.…”

Efficient synthetic access to novel N-(Pyrimidinyl)-N-(1H-benzo[d]imidazolyl)amines in an aqueous medium

“…In the same manner, the trifluoroacetylated enol ethers 2a-2j were synthesized from the trifluoroacetylation reaction of (commercially available) enol ethers [27][28][29][30] or acetals with trifluoroacetic anhydride, in the presence of pyridine. The acetals were obtained from the reaction of the respective cyclohexanone, acetophenone, 4-methoxyacetophenone, 4-methylacetophenone, 4-bromoacetophenone, 4-fluoroacetophenone, and 2-acetylthiophene, with trimethyl orthoformate and p-toluenesulfonic acid in methanol.…”

Synthesis of new trihalomethylated and non-symmetrical substituted 2-(1H-pyrazolyl)-5-(1H-pyrazolylcarbonyl)pyridines

“…Secondly, the pyrazole ring is regiospecifically prepared from the cyclocondensation reaction of the trihalomethylated vinyl I II III ketones (1, 2) with 6-hydrazinonicotinic hydrazide hydrate; and thirdly, until now transition-metal complexes involving these new heterocyclic systems are unknown. Thus, the reactions of 1,1,1-trifluoro(chloro)-4-alkyl(aryl/heteroaryl)-4-alkoxy-3-alken-2-ones (1a-i and 2c-f) [19][20][21][22][23][24][25][26][27] with 6-hydrazinonicotinic hydrazide hydrate to obtain the new pyrazolyl-pyridine system (3, 4) were carried out in a 2:1 molar ratio, respectively, in ethanol as solvent and all reactions were monitored by TLC. The most satisfactory results were obtained when the reactions were performed under mild conditions at 78 °C for 4 hours (Scheme 1).…”

“…32 In 2005, we synthesized trifluoro(chloro)methyl substituted heteroaroyl-2-pyrazolines 22 from the regiospecific reaction of 1,1,1-trifluoro(chloro)-4-methoxy-3-alken-2-ones with furoic hydrazide, 2-thiophenecarboxilic hydrazide and isonicotinic acid hydrazide. Subsequently, the dehydration reaction of the resulting 5-trifluoromethyl-1-heteroaroyl-3-phenyl-substituted 2-pyrazolines with P 2 O 5 furnished the corresponding 1H-pyrazoles as a mixture of regioisomers in low yields.…”