"Enaminonas: síntese e aplicação em reações de cicloisomerização e de acoplamento"

Abstract

This work describes the synthesis of a series of twenty 4-[alkyl (aryl) (2-propinyl amino)-3-alken-2-ones], [R2C(O)CH=C(R1)N(R)(CH2C≡CH), where R2 = CF3, CCl3, CO2Et; R1 = Me, Et, Pr e R= Pr, Ph, Bn, 4-MeC6H4] obtained with 70-95% yield throught a reaction of 1,4-addition followed by substitution between propargylamines [NH(R)(CH2C≡CH), where R= Pr, Ph, Bn, 4-MeC6H4] and 4- alkoxy-3-alken-2-ones [R2C(O)CH=C(R1)(OMe), where R2 = CF3, CCl3, CO2Et, and R1= Me, Et, Pr], using acetonitrile as solvent, room temperature or under reflux, depending on substrates used. From the series of twenty 4-[alkyl(aryl) (2-propinylamino)]-3-alken-2-ones], nine were employed in cycloisomerization reactions using AgNO3 as catalyst and CHCl3 as solvent, at room temperature, which provided a series of eight 1,2-dihydropyridine 1-(R), 5-(C(O)R2) and 6-(R1) substituted with 70-90% yield, where R = Pr, Bn, Ph, 4-MeC6H4; R1 = Me, Et, Pr; R2 = CF3, CO2Et. In only one case the cycloisomerization reaction produced a five-membered heterocycle which was characterized as 4-methyl-1-propyl-3-trifluoroacetyl pyrrole. In this work was also studied the use of dimethylamino vinyl ketones [R4C(O)CH=CHNMe2, where R4= 4-FC6H4, 4-ClC6H4, 4-BrC6H4, 4-NO2C6H4] and terminal alkynes [R3C≡C-H, where R3= Pent, Ph], using BuLi as base, BF3.OEt2 as catalyst and THF as solvent furnishing a series of eninones with 65-80% yield.