A primary-amide-functionalized metal organic framework, {[Zn 2 (2-BQBG)(BDC) 2 ]•10H 2 O} n (1) (in which 2-BQBG = 2,2′-(butane-1,4-diylbis((quinolin-2-ylmethyl)azanediyl))diacetamide and BDC = 1,4-benzenedicarboxylate), has been found to be a highly efficient hydrogen-bonddonating (HBD) heterogeneous catalyst for the Friedel− Crafts alkylation of indole with β-nitrostyrenes under mild reaction conditions (catalyst loading: 3 mol %; reaction conditions: 12 h and 35 °C). The catalyst can be easily separated from the reaction mixture by simple filtration for its reuse in four consecutive cycles with very little loss of activity. More importantly, the one-pot room temperature synthesis of 1 from the self-assembly of Zn(OAc) 2 •2H 2 O and 2-BQBG (in CH 3 OH) and Na 2 BDC (in H 2 O) can be easily scaled-up for obtaining multigram quantities in few hours. In order to showcase its versatility, the substrate scope included a variety of substituted indoles and different β-nitrostyrene derivatives forming the desired products in good to high yields. For its catalytic action, a direct proof for the key step in the proposed mechanism, based on the interaction of a primary-amide group in the 2-BQBG ligand with the nitro group of β-nitrostyrene through hydrogen bonding, is provided from the enhancement in fluorescence intensity of 1 upon successive addition of β-nitrostyrene.

This work reports the design, structural characterization, and catalytic behavior of the first example of primary amide-functionalized coordination polymers (CPs), namely, {[Cd 2 (2-bpbg)(fum) 2 (H 2 O) 2 ]•8.5H 2 O} n (1) (where 2-bpbg = N,N′-bis(2-pyridylmethyl)-1,4-diaminobutane-N,N′-diacetamide and fum = fumarate). CP 1 is synthesized from a one-pot selfassembly of starting materials in methanol under ambient conditions in excellent yield and purity, allowing an easy access to multigram quantities of it within few hours. As an example, CP 1 was used as a highly efficient heterogeneous catalyst in the carbon−carbon bond-forming Knoevenagel condensation reaction for the conversion of benzaldehyde to benzylidene malononitrile. CP 1 possesses both Lewis acidic and Brønsted basic character for the presence of unsaturated metal sites and primary amide groups, respectively, making it a highly competent bifunctional catalyst for such type of reactions. Surprisingly, on the one hand, 100% conversion was observed using only 2 mol % catalyst within 1 h at 27 °C in methanol. On the other hand, 2 mol % and 3 mol % catalyst loadings but without a solvent gives 93% and 100% conversions, respectively, in 1 h at 27 °C. CP 1 is far better than those reported in the literature. To prove the uniqueness and efficiency of the primary amide-based ligand, a similar compound with a pyridyl-based ligand was also synthesized, {[Cd 2 (tpbn)(fum) 2 ]•6H 2 O} n (2) (where tpbn = N′,N′,N″,N″-tetrakis(pyridin-2-ylmethyl)butane-1,4-diamine). With CP 2 under the same catalyst loading and conditions (2 mol %, 27 °C, 1 h), only 28% conversion was observed. This demonstrates that selective heterogeneous catalytic properties of 1 over 2 are due to the presence of the primary amide moieties and open metal sites. Moreover, CP 1 can easily be separated from the reaction mixture and reused for five consecutive cycles without significant loss of its activity. Both 1 and 2 were fully characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single-crystal and powder X-ray diffraction. These crystallize in the triclinic P1̅ space group, showing their isostructural nature and three-connected, uninodal {6 3 } honeycomb net topology.

A concise cascade strategy for the synthesis of 6H‐chromeno[4,3‐b]quinolin‐6‐ones was developed from 4‐hydroxycoumarins and arylhydrazine hydrochlorides in DMSO. The synthetic strategy relies on dual role of ammonium acetate in generating 4‐aminophenyl coumarin from arylhydrazine via aryl radical formation, and Csp2‐H formylation of coumarin using DMSO as a methine source. The strategy is scalable, and an array of arylhydrazine hydrochlorides delivered chromene‐fused quinolinones in good to excellent yields.

An Ir-catalyzed tandem strategy for the synthesis of indazolone-fused cinnolines by [4 + 2] annulation of 1-arylindazolones with α-diazo carbonyl compounds.

We describe the synthesis and structural characterization of a novel dinuclear Cu(ii) complex containing a new flexible mixed pyridine-carboxylate ligand. Single crystal X-ray diffraction reveals its uniqueness with two coordinated water molecules and four uncoordinated pyridyl groups. Utilizing the bifunctional catalytic sites, it has been found to be an efficient, robust and recyclable heterogeneous catalyst for the diastereoselective Henry (nitroaldol) reaction of aldehydes with nitroethane.

Using a new primary amide ligand 2-BPEG, four novel complexes of Cu(ii), Zn(ii) and Cd(ii) have been synthesized and fully characterized. The Cd(ii) analogue acts as an excellent heterogeneous catalyst for the solvent-free cyanosilylation reaction of an aldehyde with TMSCN.

For the Michael addition of malononitrile to 2-enoylpyridines, we report the first heterogeneous catalyst, {[Zn2(2-bpbg)­(fum)2]·4H2O·EtOH} n (1) (where 2-bpbg = N,N′-bis­(2-pyridylmethyl)-1,4-diaminobutane-N,N′-diacetamide and where fum = fumarate), which is decorated with primary amide side arms. It is prepared from the self-assembly of starting materials in methanol at room temperature (27 °C). Using 3 mol % of 1, greater than 99% conversion of substrates to the desired product is achieved within 1 h at 27 °C. Moreover, the catalyst is recyclable up to five consecutive cycles without significant loss of activity and structural integrity. In order to show the uniqueness of 1, the reaction under the same conditions was catalyzed by a fully pyridyl-based (i.e., having no primary amide group) and isostructural analogue, {[Zn2(tpbn)­(fum)2]·6H2O} n (2) (where tpbn = N′,N′,N″,N′′-tetrakis­(pyridin-2-ylmethyl)­butane-1,4-diamine), but resulting only in 7% conversion. This demonstrates the selective catalytic activity of 1 over 2 due to the presence of the primary amide side arms, where it acts as a bifunctional catalyst through the excellent hydrogen bond donating (HBD) ability in this reaction. For providing an insight into its mechanism of action involving a cyclic seven-membered hydrogen bonding motif, the reaction was performed with freshly synthesized (E)-chalcone, 3-enoylpyridine, and 4-enoylpyridine instead of 2-enoylpyridine under the same conditions. In the case of (E)-chalcone no product formation was observed, whereas for 3-enoylpyridine and 4-enoylpyridine the conversions were only 29% and 25%, respectively. Both 1 and 2 were fully characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, and single-crystal and powder X-ray diffraction.

The present work deals with the development of cocrystal of ambrisentan (AMT) to improve its biopharmaceutical profile. Full interaction maps (FIM) of AMT were explored to find out the potential sites for hydrogen bonding and prediction of supramolecular synthons. This information was further applied to the screening of amino acids as prospective coformers for cocrystallization of AMT. Mechanochemical reactions have resulted in two cocrystals with L-aspartic acid and glycylglycine (dipeptide). The crystal structural analysis revealed that the hydrogen-bonding pattern in the developed cocrystals corroborated well with the predicted supramolecular synthons. The developed cocrystals showed a remarkable improvement in solubility, intrinsic dissolution rate, and in vivo systemic absorption as compared to the parent drug. Complementarily, Hirshfeld surface maps together with crystal features established a good structural−performance correlation of the developed cocrystals. Thus, the systematic cocrystallization driven by structural informatics tools is valuable in the development of novel solid forms with improved biopharmaceutical attributes.