Search results for "Reaction sequence"
showing 3 items of 13 documents
A new strategy for the synthesis of fluorinated 3,4-dihydropyrimidinones
2009
A new family of 3,4-dihydropyrimidinones (DHPMs) bearing fluorinated substituents at C6 have been prepared from gem-difluorinated nitriles, alkyl 3-butenoates and iso(thio)cyanates. This novel Biginelli-type process relies on the gamma-addition of the ester-derived enolate to fluorinated nitriles. A tandem nucleophilic addition aza-Michael reaction sequence completes the synthetic process. (C) 2009 Elsevier B.V. All rights reserved.
ChemInform Abstract: Cyclocondensation of α-Aminonitriles and Enones: A Short Access to 3,4-Dihydro-2H-pyrrole 2-Carbonitriles and 2,3,5-Trisubstitut…
2010
The reaction of α,β-unsaturated carbonyl compounds with aminoacetonitrile hydrochloride furnishes 3,5-disubstituted 3,4-dihydro-2H-pyrrole-2-carbonitriles in a one-pot reaction sequence. While these products can serve as starting materials for the preparation of polysubstituted pyrrolizidines, they are kinetically stable against the base-induced elimination of HCN. In contrast, their 2-substituted analogues obtained from α-substituted α-aminonitriles can be readily converted to the corresponding 2,3,5-trisubstituted pyrroles under microwave irradiation. The key step presumably involves the thermal electrocyclization of a stabilized 2-azapentadienyl anion formed by condensation of the reacta…
Addition of α-Aminonitriles to α,β-Unsaturated Carbonyl Compounds: A One-Pot Synthesis of Polysubstituted Pyrrolidines.
2003
The vinylogous addition of deprotonated N-alkyl-α-aminonitriles to α,β-unsaturated carbonyl compounds yields cyclic intermediates which can be reduced to form polysubstituted pyrrolidines in a one-pot reaction sequence. Since the cyano substituent is lost in the reduction step, the aminonitriles serve as easily accessible (N-alkylamino)-substituted carbanion equivalents.