27748-49-8Relevant academic research and scientific papers
Synthesis and characterization of Piperidine-4-carboxylic acid functionalized Fe3O4 nanoparticles as a magnetic catalyst for Knoevenagel reaction
Karaoglu,Baykal,?enel,S?zeri,Toprak
, p. 2480 - 2486 (2012)
Piperidine-4-carboxylic acid (PPCA) functionalized Fe3O 4 nanoparticles as a novel organic-inorganic hybrid heterogeneous catalyst was fabricated and characterized by XRD, FT-IR, TGA, TEM and VSM techniques. Composition was determined as Fe3O4, while particles were observed to have spherical morphology. Size estimations using X-ray line profile fitting (10 nm), TEM (11 nm) and magnetization fitting (9 nm) agree well, revealing nearly single crystalline character of Fe 3O4 nanoparticles. Magnetization measurements reveal that PPCA functionalized Fe3O4 NPs have superparamagnetic features, namely immeasurable coercivity and absence of saturation. Small coercivity is established at low temperatures. The catalytic activity of Fe 3O4-PPCA was probed through one-pot synthesis of nitro alkenes through Knoevenagel reaction in CH2Cl2 at room temperature. The heterogeneous catalyst showed very high conversion rates (97%) and could be recovered easily and reused many times without significant loss of its catalytic activity.
Insights into the diastereoselective control in the sulfa-Michael addition of thiols to nitroalkenes: Stereoelectronic effect in the cyclic chelated transition state
Wang, Jiandong,Li, Pingfan,Yang, Zhanhui,Chen, Ning,Xu, Jiaxi
, p. 370 - 378 (2015/12/31)
The diastereoselective control in the sulfa-Michael addition of nitroalkenes and lithium thiolates followed by protonation was investigated. Lithium thiolates first added to nitroalkenes to afford cyclic lithium-chelated nitronates. The subsequent kinetic protonation of nitronates was proved to be the stereochemical determinant through the chelate-controlled six-membered half-chair transition state bearing two approximately 1,2-diaxial substituents due to stereoelectronic effect control. The stereoelectronic effect in the cyclic chelated transition state was probed and verified by tuning the steric bulkiness of the corresponding substituents. The reaction involving 1-nitrocyclohexene provided perfect support for the proposed diastereoselective control model. The current investigation provided not only comprehensive insights into the diastereoselective control in the sulfa-Michael addition of nitroalkenes and thiolates, but also an important role of the stereoelectronic effect in certain organic reactions involving cyclic chelate transition states.
Chemo-enzymatic synthesis of a multi-useful chiral building block molecule for the synthesis of medicinal compounds
Nakano, Toshiki,Yagi, Yusuke,Miyahara, Mizuki,Kaminura, Akio,Kawatsura, Motoi,Itoh, Toshiyuki
experimental part, p. 6747 - 6757 (2011/10/18)
Optical resolution of 2-methyl-2-nitrobut-3-en-1-ol has been accomplished using a low-temperature lipase-catalyzed transesterification carried out at -40°C.
Reactions of O,O-Diprotonated Nitro Olefins with Benzenes. Formations of Phenylacetones, 4H-1,2-Benzoxazines and Biarylacetone Oximes
Ohwada, Tomohiko,Okabe, Kazuaki,Ohta, Toshiharu,Shudo, Koichi
, p. 7539 - 7555 (2007/10/02)
O,O-Diprotonated nitro olefins undergo three alternative electrophilic reactions which yield α-phenylacetones, 4H-1,2-benzoxazines and biphenylacetone oximes depending on the reaction conditions (temperature and time) and aromatic substrates.Although these reactions are seemingly divergent, a common intermediate of a phenylated protonated aci-nitro species, derived from the dication, is postulated to be involved in the reactions.Furthermore, the formation of benzoxazines and biphenylacetone oximes can be interpreted in terms of participation of novel chemical species with phenylethylene dication character derived from the common intermediate.
