A concise method to synthesize 1-substituted 4-amino-2-(trifluoromethyl)-1H-pyrroles from the heterocyclization reaction of 5-bromo-4-methoxy-1,1,1-trifluoropent-3-en-2-ones with amines is described. This method has the following advantages: it uses a wide range of primary amines, starting materials are easily available, it is simple to perform, the reaction conditions are mild, it is environmentally friendly, and it furnishes yields of up to 98%.

5‐Bromo‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one was used as an efficient precursor for the synthesis of a new series of (1,2,3‐triazol‐1‐yl)methyl‐pyrimidine biheterocycles. For this stepwise synthesis, the 5‐bromo‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one was first converted into 5‐azido‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one through a nucleophilic substitution of the bromine by an azide group. This was then followed by an azide–alkyne cycloaddition reaction (click chemistry) to give the key intermediate 5‐[4‐alkyl(aryl)‐1H‐1,2,3‐triazol‐1‐yl]‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐ones. These were cyclocondensed with 2‐methylisothiourea sulfate to give a series of 2‐(methylthio)‐4‐(1,2,3‐triazol‐1‐yl)methyl‐6‐(trifluoromethyl)pyrimidines. Additionally, the 2‐methylthiopyrimidine products were used to prepare a new series of 2‐amino‐4‐(1,2,3‐triazol‐1‐yl)methyl‐6‐(trifluoromethyl)pyrimidines.

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This study describes an improved one-pot, four-step synthesis of a new series of 1-aryl-3-trifluoroacetyl pyrroles from the reaction of 3-trifluoroacetyl-4,5-dihydrofuran with arylamines, giving 1,1,1-trifluoro-3-(2-hydroxyethyl)-4-arylamino-3-buten-2-ones, which were directly submitted to Swern oxidation to furnish 1,1,1-trifluoro-3-(2-ethanal)-4-arylamino-3-buten-2-ones. Subsequent intramolecular cyclization of the corresponding enaminoaldehydes followed by aromatization rendered the title compounds in a 30 to 56% overall yield.

In this work, the reactivity of 5-bromo-1,1,1-trifluoro-4-methoxypent-3-en-2-one toward primary aliphatic amines was studied. The reaction was found to be extremely selective to synthesize a series of 1-alkyl-4-aminoalkyl-2-trifluoromethyl-1H-pyrroles (13 examples, at yields up to 90%) and a series of highly functionalized β-enaminones (6 examples, at yields up to 78%), with only the amount of amine and the reaction condition needing to be controlled. The structure of the products was unambiguously determined by single crystal X-ray diffraction and 2D NMR experiments.

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Chemoselective Synthesis of 1-Substituted 4-Amino-2-(trifluoromethyl)--1H-pyrroles Through the Heterocyclization Reaction of 4-Methoxy-5-bromo--1,1,1-trifluoropent-3-en-2-ones with Amines. -(AQUINO, E. D. C.; LEONEL, G.; GARIBOTI, V. C.; FRIZZO, C. P.; MARTINS, M. A. P.; BONACORSO, H. G.; ZANATTA*, N.; J. Org. Chem. 80 (2015) 24, 12453-12459, http://dx.

An Efficient Two-Step Synthesis of New 5-Substituted-1H-tetrazoles of Biological Interest. -Cycloaddition reactions between the nitrile group of β-cyanocarboxylic acids with sodium azide in the presence of zinc chloride afford tetrazolic acids, structural analogues of succinic acid. -(ZANATTA*, N.; DA SILVA, F. M.; DA SILVA, A. M. P. W.; AQUINO, E. D. C.; BONACORSO, H. G.; MARTINS, M. A. P.; J. Heterocycl. Chem. 50 (2013) 4, 868-873, http://dx.