Alum as an efficient catalyst for the multicomponent synthesis of functionalized piperidines
作者:Ramneet Kaur、Annah Gupta、Kamal K. Kapoor
DOI:10.1007/s11164-017-2979-3
日期:2017.11
An effective approach to the synthesis of functionalized piperidines via a one-pot multicomponent reaction of aniline, β-ketoester and aldehyde in the presence of alum as an efficient catalyst has been reported. The present procedure offers advantages such as simple workup, short reaction time and offers rapid access to a variety of functionalized piperidines.
Cyanuric chloride catalyzed metal-free mild protocol for the synthesis of highly functionalized tetrahydropyridines
作者:Rathinam Ramesh、Subramani Maheswari、Mani Arivazhagan、Jan Grzegorz Malecki、Appaswami Lalitha
DOI:10.1016/j.tetlet.2017.08.074
日期:2017.10
condensation of ethyl acetoacetate, anilines and aromatic aldehydes under mild reaction conditions has been described. This domino strategy allows rapid cyclization in the presence of 10 mol% of cyanuric chloride as a source of hydrochloric acid to afford the desired target skeletons in excellent yields. The present protocol offers prominent advantages of simple operational procedure, metal-free organocatalyst
Aluminized polyborate: a novel catalyst for the multicomponent solvent-free synthesis of alkyl 1,2,6-trisubstituted-4-[(hetero)arylamino]-1,2,5,6-tetrahydropyridine-3-carboxylates
作者:Anil S. Mali、Chinmay S. Potnis、Ganesh U. Chaturbhuj
DOI:10.1007/s13738-018-1340-0
日期:2018.6
An efficient and simple method for the one-pot three-component synthesis of alkyl 1,2,6-trisubstituted-4-[(hetero)arylamino]-1,2,5,6-tetrahydropyridine-3-carboxylates was developed using aromatic aldehyde, amine and β-ketoesters catalyzed by aluminized polyborate, an efficient reusable catalyst under solvent-free condition. Aluminized polyborate has advantageous of cost, ecologically benefits, accessible preparation and recyclability up to five cycles along with high product yield and simplicity.
Polyphosphoric acid–zirconia pillared clay composite catalytic system for efficient multicomponent one pot synthesis of tetrahydropyridines under environmentally benign conditions
作者:Purabi Kar、B.G. Mishra、S.R. Pradhan
DOI:10.1016/j.molcata.2014.02.024
日期:2014.6
A series of zirconia pillared clay-polyphosphoric acid (PPA) composites are synthesized by adopting different preparative strategies. Initially, PPA is intercalated to the clay matrix with and without the use of structure expanding agent (CTAB). Subsequently, the PPA-clay composite is pillared with Zrpolycation to form the composite materials. In an alternate approach, Zr-pillared clay is synthesized by insertion of Zr-polycation, which is then used for dispersion of PPA moiety in the pillared clay matrix. The synthesized composites are characterized by XRD, FTIR, UV-vis, TGA, EDX, FE-SEM and sorptometric techniques. XRD study indicated an expansion in the clay structure after intercalation of PPA as well as the Zr-polycations. The FTIR spectra exhibit characteristic vibrational features of the clay sheet as well as PPA moiety indicating the structural stability of the composite materials. The phosphorous content in the composite samples is analyzed using EDX study. FE-SEM study indicated morphological changes upon intercalation of PPA and Zr-polycations to the clay matrix. The catalytic activity of the composite catalysts has been examined for the synthesis of tetrahydropyridines under environmental benign conditions by one pot multicomponent condensation of beta-dicarbonyl compounds, substituted anilines and substituted benzaldehydes. The PPA intercalated clay pillared with Zr polycations (PPA-ZrP) is found to be highly efficient for the synthesis of structurally diverse substituted tetrahydropyridines under mild conditions. (C) 2014 Elsevier B.V. All rights reserved.