- Dimethylamine substitution in N,N-dimethyl enamines. Synthesis of aplysinopsin analogues and 3-aminotetrahydrocoumarin derivatives
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Some new six-membered aplysinopsin analogues were prepared from 5-dimethylaminomethylidene-2,4,6(1H,3H,5H)-pyrimidinetriones and indole derivatives. Also 2-[[(2,4,6-trioxohexahydropyrimidin-5-ylidene)methyl]amino]-3- dimethylaminopropenoates were synthesized and employed in the synthesis of fused 2H-pyran-2-ones.
- Seli?, Lovro,Stanovnik, Branko
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- Cyclic Bis-porphyrin-Based Flexible Molecular Containers: Controlling Guest Arrangements and Supramolecular Catalysis by Tuning Cavity Size
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Three cyclic zinc(II) bis-porphyrins (CB) with highly flexible linkers are employed as artificial molecular containers that efficiently encapsulate/coordinate various aromatic aldehydes within their cavities. Interestingly, the arrangements of guests and their reactivity inside the molecular clefts are significantly influenced by the cavity size of the cyclic containers. In the presence of polycyclic aromatic aldehydes, such as 3-formylperylene, as a guest, the cyclic bis-porphyrin host with a smaller cavity (CB1) forms a 1:1 sandwich complex. Upon slightly increasing the spacer length and thereby the cavity size, the cyclic host (CB2) encapsulates two molecules of 3-formylperylene that are also stacked together due to strong π–π interactions between them and CH–π interactions with the porphyrin rings. However, in the cyclic host (CB3) with an even larger cavity, two metal centers of the bis-porphyrin axially coordinate two molecules of 3-formylperylene within its cavity. Different arrangements of guest inside the cyclic bis-porphyrin hosts are investigated by using UV/Vis, ESI-MS, and 1H NMR spectroscopy, along with X-ray structure determination of the host–guest complexes. Moreover, strong binding of guests within the cyclic bis-porphyrin hosts support the robust nature of the host–guest assemblies in solution. Such preferential binding of the bis-porphyrinic cavity towards aromatic aldehydes through encapsulation/coordination has been employed successfully to catalyze the Knoevenagel condensation of a series of polycyclic aldehydes with active methylene compounds (such as Meldrum's acid and 1, 3-dimethylbarbituric acid) under ambient conditions. Interestingly, the yields of the condensed products significantly increase upon increasing spacer lengths of the cyclic bis-porphyrins because more substrates can then be encapsulated within the cavity. Such controllable cavity size of the cyclic containers has profound implications for constructing highly functional and modular enzyme mimics.
- Mondal, Pritam,Sarkar, Sabyasachi,Rath, Sankar Prasad
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supporting information
p. 7093 - 7103
(2017/05/29)
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- Design, synthesis and anticancer activities of hybrids of indole and barbituric acids-Identification of highly promising leads
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By combining the structural features of indole and barbituric acid, new hybrid molecules were designed and synthesized. Evaluations of these molecules over 60 cell line panel of human cancer cells have identified two molecules with significant anticancer activities. Dockings of two active molecules in the active sites of COX-2, thymidylate synthase and ribonucleotide reductase indicate their strong interactions with these enzymes.
- Singh, Palwinder,Kaur, Matinder,Verma, Pooja
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scheme or table
p. 3054 - 3058
(2010/02/28)
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- Reductive C-alkylation of barbituric acid derivatives with carbonyl compounds in the presence of platinum and palladium catalysts
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Effective synthetic procedures for the preparation of mono- and di-C-alkylated barbituric acid derivatives through palladium and platinum catalytic hydrogenation of solutions of barbituric acids (unsubstituted, N-mono, and N,N′-disubstituted barbituric acids) and carbonyl compounds (aliphatic and aromatic aldehydes and ketones).
- Jursic, Branko S.,Neumann, Donna M.
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p. 4103 - 4107
(2007/10/03)
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