10.6084/m9.figshare.5303308
Wystan K. O. Teixeira
Wystan K. O.
Teixeira
Helena A. Gonçalves
Helena A.
Gonçalves
Débora L. de Mello
Débora L.
de Mello
Sidnei Moura
Sidnei
Moura
Darlene C. Flores
Darlene
C. Flores
Alex F. C. Flores
Alex
F. C. Flores
Cyclocondensation between fatty acid hydrazides and 1,1,1-trifluoro-4-alkoxy-3-alken-2-ones: Introducing a trifluoromethylated head onto fatty acid moieties
Taylor & Francis Group
2017
1,1,1-Trifluoro-4-alkoxy-3-alken-2-ones
5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-pyrazoles
[3 + 2] cyclocondensation
fatty hydrazides
2017-08-11 13:50:51
Journal contribution
https://tandf.figshare.com/articles/journal_contribution/Cyclocondensation_between_fatty_acid_hydrazides_and_1_1_1-trifluoro-4-alkoxy-3-alken-2-ones_Introducing_a_trifluoromethylated_head_onto_fatty_acid_moieties/5303308
<p>This paper reports the regioselective synthesis of new trifluoromethylated lipid derivatives, namely, 1-(5-hydroxy-5-trifluoromethyl-3-alkyl-4,5-dihydro-1<i>H</i>-pyrazol-1-yl)alkan-1-ones, through cyclocondensation reactions between a series of fatty hydrazides (palmitoyl, stearoyl, and oleoyl hydrazides) obtained from fatty acids from renewable resources (1,1,1-trifluoro-4-alkoxy-3-alken-2-ones [F<sub>3</sub>CC(O)CH˭C(R<sup>1</sup>)OR, where R<sup>1</sup> = H and R˭Et; R<sup>1</sup> = –(CH<sub>2</sub>)<sub>6</sub>CH<sub>3</sub>, –(CH<sub>2</sub>)<sub>6</sub>CH<sub>3</sub>, –(CH<sub>2</sub>)<sub>8</sub>CH<sub>3</sub>, –(CH<sub>2</sub>)<sub>9</sub>CH<sub>3</sub>, –(CH<sub>2</sub>)<sub>10</sub>CH<sub>3</sub>, –(CH<sub>2</sub>)<sub>12</sub>CH<sub>3</sub>, –(CH<sub>2</sub>)<sub>2</sub>Ph], and R˭Me). Experimental observations showed that the lipophilic characteristic of 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1<i>H</i>-pyrazoles (<b>5–7</b>) prevent the acid catalyzed dehydration to aromatization of 1<i>H</i>-pyrazole ring, although in some cyclocondensations a proportion of the aromatic derivative 1-(5-trifluoromethyl-3-alkyl-1<i>H</i>-pyrazol-1-yl)alkan-1-one was obtained. All products were characterized using multinuclear (<sup>1</sup>H, <sup>13</sup>C, <sup>19</sup>F) NMR spectroscopy.</p>