Novel Bispidine-Monoterpene Conjugates—Synthesis and Application as Ligands for the Catalytic Ethylation of Chalcones

Abstract

A number of new chiral bispidines containing monoterpenoid fragments have been obtained. The bispidines were studied as ligands for Ni-catalyzed addition of diethylzinc to chalcones. The conditions for chromatographic analysis by HPLC-UV were developed, in which the peaks of the enantiomers of all synthesized chiral products were separated, which made it possible to determine the enantiomeric excess of the resulting mixture. It was demonstrated that bispidine-monoterpenoid conjugates can be used as the ligands for diethylzinc addition to chalcone C=C double bond but not as inducers of chirality. Besides products of ethylation, formation of products of formal hydrogenation of the chalcone C=C double bond was observed in all cases. Note, that this formation of hydrogenation products in significant amounts in the presence of such catalytic systems was found for the first time. A tentative scheme explaining the formation of all products was proposed.

Novel Complexes of 3-[3-(1H-Imidazol-1-yl)propyl]-3,7-diaza-bispidines and β-Cyclodextrin as Coatings to Protect and Stimulate Sprouting Wheat Seeds

“…The initial reagents were obtained from Sigma-Aldrich: 3-(1 H -imidazol-1-yl)propan-1-amine ( 3 ) and 1-Boc-piperidin-4-one ( 4 ), but 1-(3-butoxypropyl)piperid-4-one ( 5 ) was synthesized [ 16 ]. The NMR signals found for the bispidines and bispidinones were close to related but different systems [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Elemental analyses were performed on new compounds by Atlantic Microlabs (Norcross, GA, USA).…”

Reaction of β-Nitrostyrene with Diethyl Malonate in the Presence of Bispidines: The Unusual Role of the Organocatalyst

“…The initial study featured symmetric N,N ′ -dialkyl bispidines 1 [42] and 2 [57], containing monoterpene and benzyl fragments, respectively, as possible organocatalysts. At the first stage of the work, the following initial conditions for catalytic reactions were chosen according to [52,53]: 1 eq.…”

“…Bispidine, or 3,7-diazabicyclo [3.3.1]nonane, is of great interest as a basis for the creation of catalysts in asymmetric synthesis due to its conformational rigidity and the presence of two nitrogen atoms, which opens up wide possibilities in terms of functionalization and the potential for supramolecular interactions. Indeed, chiral bispidines are used as ligands in metal-complex catalysts of asymmetric variants of Henry reactions [36][37][38], the addition of diethyl zinc to aldehydes [39,40], chalcones [41,42] and enones [43], the hydrogenation of C=C bonds [44], the oxidative kinetic separation of secondary alcohols [45], deprotonation [46], and cyclopropanation [47].…”

Synthesis and Aminomethylation of 2-Amino-4-(2-chlorophenyl)-6-(dicyanomethyl)-1,4-dihydropyridine-3,5-dicarbonitrile N-Methylmorpholinium Salt

“…3,7-Diazabicyclo[3.3.1]nonanes (bispidins) and related compounds are widely used as biologically active compounds [38,39], complexing agents for metals [40], radionuclides [41], as initial reagents for the synthesis of natural compounds [42], materials for imaging in positron emission tomography [43], platforms for chiral catalysts [44,45]. Recently, 3,7-diazabicyclononane derivatives have been successfully used as initial templates for constructing complex supramolecular assemblies [46][47][48][49].…”