15728-35-5Relevant academic research and scientific papers
One Robust Microporous TmIII-Organic Framework for Highly Catalytic Activity on Chemical CO2Fixation and Knoevenagel Condensation
Chen, Hongtai,Hu, Tuoping,Fan, Liming,Zhang, Xiutang
, p. 1028 - 1036 (2021)
In terms of documented references, multifunctional MOFs with high catalytic performance could be constructed from the combination of metal cations and polycarboxyl-pyridine ligands, which could efficiently endow crystallized porous frameworks with the coexisting Lewis acid-base properties. Thus, by employing a ligand-directed synthetic strategy, the exquisite combination of wave-like inorganic chains of [Tm(CO2)3(OH2)]n and mononuclear units of [Tm(CO2)4(OH2)2] with the aid of the specially designed ligand of 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H5BDCP) generates one highly robust microporous framework of {(Me2NH2)[Tm3(BDCP)2)(H2O)3]·4DMF·H2O}n (simplified as NUC-25), which contains near-rectangular nanochannels and large solvent-residing voids. Furthermore, the activated state of NUC-25 with the removal of associated water molecules is a rarely reported bifunctional heterogeneous catalyst due to the coexistence of Lewis acid-base sites including 6-coordinated Tm3+ ions, uncoordinated carboxyl oxygen atoms, and Npyridine atoms. Just as expected, NUC-25 exhibits greatly high catalytic activity for the cycloaddition reaction of epoxides with CO2 into alkyl cyclic carbonates under bland solvent-free conditions, which should be ascribed to the polarity of nitrogen-containing pyridine heterocycles as Lewis base sites on the inner surface of nano-caged voids except for recognized Lewis acid sites of rare earth cations. Moreover, the excellent pore-size-dependent catalytic property for Knoevenagel condensation reactions confirms that NUC-25 can be viewed as a recyclable bifunctional heterogeneous catalyst. Therefore, these results strongly demonstrate that microporous MOFs assembled from pre-designed polycarboxyl-heterocyclic ligands display better catalytic performance not only for chemical CO2 fixation but also for Knoevenagel condensation reactions.
Nanochannel {InZn}-Organic Framework with a High Catalytic Performance on CO2Chemical Fixation and Deacetalization-Knoevenagel Condensation
Chen, Hongtai,Zhang, Zhengguo,Hu, Tuoping,Zhang, Xiutang
, p. 16429 - 16438 (2021/11/01)
The rare combination of InIII 5p and ZnII 3d in the presence of a structure-oriented TDP6- ligand led to a robust hybrid material of {(Me2NH2)[InZn(TDP)(OH2)]·4DMF·4H2O}n (NUC-42) with the interlaced hierarchical nanochannels (hexagonal and cylindrical) shaped by six rows of undocumented [InZn(CO2)6(OH2)] clusters, which represented the first 5p-3d nanochannel-based heterometallic metal-organic framework. With respect to the multifarious symbiotic Lewis acid-base and Br?nsted acid sites in the high porous framework, the catalytic performance of activated NUC-42a upon CO2 cycloaddition with styrene oxide was evaluated under solvent-free conditions with 1 atm of CO2 pressure, which exhibited that the reaction could be well completed at ambient temperature within 48 h or at 60 °C within 4 h with high yield and selectivity. Moreover, because of the acidic function of metal sites and a central free pyridine in the TDP6- ligand, deacetalization-Knoevenagel condensation of acetals and malononitrile could be efficiently facilitated by an activated sample of NUC-42a under lukewarm conditions.
Preparation of O-Protected Cyanohydrins by Aerobic Oxidation of α-Substituted Malononitriles in the Presence of Diarylphosphine Oxides
Zhang, Dapeng,Lian, Mingming,Liu, Jia,Tang, Shukun,Liu, Guangzhi,Ma, Cunfei,Meng, Qingwei,Peng, Haisheng,Zhu, Daling
supporting information, p. 2597 - 2601 (2019/04/17)
A mild, reagent-cyanide-free, and efficient synthesis of O-phosphinoyl-protected cyanohydrins from readily available α-substituted malononitriles was realized using diarylphosphine oxides in the presence of O2. Mechanistic studies indicated that in addition to the initial aerobic oxidation of the malononitrile derivative notable features of this process include the formation of a tetrahedral intermediate and a subsequent intramolecular rearrangement. The phosphinoyl-protecting group can be removed by alcoholysis or by reduction with DIBAL-H.
BICYCLIC PYRIMIDINES AS DIPEPTIDYL PEPTIDASE-IV INHIBITORS FOR THE TREATMENT OR PREVENTION OF DIABETES
-
Page/Page column 42; 43, (2008/06/13)
The present invention is directed to novel substituted bicyclic pyrimidines which are inhibitors of the dipeptidyl peptidase-IV enzyme ("DPP-IV inhibitors") and which are useful in the treatment or prevention of diseases in which the dipeptidyl peptidase-IV enzyme is involved, such as diabetes and particularly Type 2 diabetes. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which the dipeptidyl peptidase-IV enzyme is involved.
Synthesis of substituted 6-amino-4-aryl-5-cyano-2h,4h-pyrano[2,3-c]pyrazoles. Crystal and molecular structure of 6-amino-5-cyano-3-methyl-4-(2′,4′,6′-triethylphenyl)-2h,4h -pyrano[2,3-c]pyrazole
Shestopalov,Yakubov,Tsyganov,Emel'yanova,Nesterov
, p. 1180 - 1189 (2007/10/03)
Substituted 6-aminopyrano[2,3-c]pyazoles were synthesized by the two-component condensation of arylidenemalononitriles and substituted 5-pyazolones or three-component condensation of aromatic aldehydes, malononitrile, and substituted 5-pyazolones. It was
