Synthesis of Highly Substituted 2,3-Dihydro-1H-pyrrole Derivatives via a Tandem Regioselective Addition of Nitrones to 1,3-Enynes with Subsequent Rearrangement

Abstract

A novel method for the synthesis of 1,3-enynes is described through oxidative cyclization of the semicarbazones of Michael adducts having potential nitrile functionality. Reaction of these 1,3-enynes with diaryl nitrones has yielded a diastereomeric mixture of highly substituted 2,3-dihydro-1H-pyrrole derivatives via a tandem regioselective addition with subsequent rearrangement.

3-(4-Methylphenyl)-1-phenyl-3-(4,5,6,7-tetrahydro-1,2,3-benzoselenadiazol-4-yl)propan-1-one

“…The five-membered 1,2,3-selenadiazole moiety (C1/N1/N2/Se1/C2) of the title compound adopts a planar conformation as observed in the selenadiazole moieties of several crystal structures (Arsenyan et al, 2007;Saravanan et al, 2006a;Saravanan et al, 2006b;Saravanan et al, 2007;Saravanan et al, 2008;Marx et al, 2007;Marx et al, 2008a;Marx et al, 2008b;Gunasekaran et al, 2007a;Gunasekaran et al, 2007b). Cremer & Pople puckering analysis (Cremer & Pople, 1975) cannot be performed, for its weighted average absolute torsion angle is 0.89°, which is less than 5.0°.…”

“…For bond lengths in compounds containing a 1,2,3-selenadiazole group, see: Arsenyan et al (2007); Saravanan et al (2006aSaravanan et al ( ,b, 2007Saravanan et al ( , 2008; Marx et al (2007Marx et al ( , 2008a; Gunasekaran et al (2007a,b). For biological applications of 1,2,3-selenadiazole derivatives, see: Kuroda et al (2001); El-Bahaie et al (1990); El-Kashef et al (1986); Plano et al (2010); Padmavathi et al (2002).…”

“…Considering the importances of the 1,2,3-selenadiazole derivatives, we present herein the single-crystal structure analysis of the title compound. The bond lengths of the 1,2,3-selenadiazole moiety in the title compound are comparable to those observed for selenadiazole moieties in several crystal structures such as 4-methyl-5-ethoxycarbonyl-1,2,3-selenadiazole phenylboronic acid (Arsenyan et al, 2007), diethyl 2-((4-methylphenyl)(4-phenyl-1,2,3-selenadiazol-5-yl)methyl)malonate (Saravanan et al, 2006a), 4-(4-chlorophenyl)-5-(1-(4-methoxyphenyl)-2-methyl-2-nitropropyl)-1,2,3-selenadiazole (Saravanan et al, 2006b), 3-(4-methylphenyl)-3-(4-(4-methylphenyl)-1,2,3-selenadiazol-5-yl)-2-phenylpropanenitrile , ethyl (Z)-3-(4-chlorophenyl)-2-cyano-3-(4-phenyl-1,2,3-selenadiazol-5-yl)prop-2-enoate (Saravanan et al, 2008), 5-(2-methyl-2-nitro-1-phenylpropyl)-4-phenyl-1,2,3-selenadiazole (Marx et al, 2007), 4-(4-Chlorophenyl)-5-(1-(4-chlorophenyl)-2-methyl-2-nitropropyl)-1,2,3-selenadiazole (Marx et al, 2008a), diethyl 2-((4-nitrophenyl)(4-phenyl-1,2,3-selenadiazol-5-yl)methyl)malonate (Marx et al, 2008b), 5-[2-methyl-1-(4-methylphenyl)-2-nitropropyl]-4-phenyl-1,2,3-selenadiazole (Gunasekaran et al, 2007a) and 4-(4-chlorophenyl)-5-[2-methyl-1-(4-methylphenyl)-2-nitropropyl]-1,2,3-selenadiazole (Gunasekaran et al, 2007b). The molecular structure of the title compound is shown in Fig.…”

One-pot preparation of substituted pyrroles from α-diazocarbonyl compounds

“…More recently, Yadav and co-workers [ 24 ] described an efficient protocol for the synthesis of sugar derived optically active di-pyrrolyl and bis-indolyl alkanols that are important for the synthesis of porphyrins, using montmorillonite KSF as catalyst. The search for short procedures for the synthesis of highly functionalized pyrrole derivatives is still desirable [ 25 – 27 ].…”

Ionic Liquid as Soluble Support for Synthesis of 1,2,3-Thiadiazoles and 1,2,3-Selenadiazoles

“…Figure 1 depicts chemical structures of selected bioactive 1,2,3-thiadiazoles. Furthermore, they have been utilized as intermediates for the synthesis of organic compounds such as dihydroselenophenes 14,15 and 2,3-dihydro-1H-pyrroles 16 . 7 1,2,3-Selenadiazoles are bioisosteric heterocycle of 1,2,3-thiadiazoles and have attracted attention due to their diverse biological activities such as antibacterial, 8,9 antifungal, 10 anticancer, 11,12 and anti-HIV 13 activities.…”