Long-Guan Zhu

Synthesis of Heterocyclic [3.3.3]Propellanes via a Sequential Four-Component Reaction

A highly chemoselective heteroannulation protocol for the synthesis of unreported polysubstituted heterocyclic [3.3.3]propellanes has been developed by sequential four-component reaction of ninhydrin, malononitrile, primary amines, and dialkyl acetylenedicarboxylates under mild conditions in water. To the best of our knowledge, there are no previous reports for the synthesis of these classes of heterocyclic [3.3.3]propellanes. The merit of this sequential Knoevenagel condensation/enamine formation/Michael addition/cyclization sequence is highlighted by its high atom-economy, excellent yields, the use of water as reaction media, and the efficiency of production without the use of any activator or metal promoters. This synthesis serves as a nice addition to group-assistant-purification (GAP) chemistry in which purification via chromatography and recrystallization can be avoided, and the pure products were obtained simply by washing the crude products with 95% ethanol.

Syntheses and crystal structures of three one-dimensional copper(II) complexes constructed by salicylate and 4,4 '-bipyridine: ladder, zig-zag, and linear polymeric assembly

Syntheses and crystal structures of three new compounds { trans -[Cu(Hsal) 2 (4,4′-bipy)](DMF)} n ( 1 ), { cis -[Cu(Hsal) 2 (4,4′-bipy)](2H 2 O)} n ( 2 ), and [Cu 2 (Hsal) 4 (4,4′-bipy)] n ( 3 ) are reported. These three compounds have trans -, cis -, and dimer geometries bearing a common motif [Cu(Hsal) 2 (4,4-bipy) n ] leading to ladder, zig-zag, and linear one-dimensional (1-D) networks, respectively. The Cu⋯Cu distances separated by 4,4′-bipy are different in these three compounds, which leads to an extension structure in compound 3 and a compact structure in compound 2 . Conformations of 4,4′-bipy ligands in these three compounds are also different. In compound 1 there is stacking of the bidentate salicylate and the bridging salicylate from another molecule. There is also stacking of salicylate and 4,4′-bipy from another molecule in compound 2 .

The dimeric and two-dimensional copper(II) complexes constructed from salicylic acid and 4,4 '-bipyridine

Abstract Two novel complexes, [Cu2(Hsal)4(4,4′-bipyridine)(H2O)2(DMF)2] (1) (H2sal=salicylic acid) and {[Cu(Hsal)2(4,4′-bipyridine)](H2O)(H2sal)}n (2), were synthesized by layered-solution method and structurally characterized. Geometries of copper atoms in both complexes exhibit square pyramidal. Complex 1 is a dimer and hydrogen bonds between water and DMF molecules extend the structure into 1D hydrogen bonding network. Complex 2 consists of two-dimensional square framework structure.

Novel three-component route to diastereoselective synthesis of trisubstituted vinylphosphonates using phosphites, acetylenic esters, and aroyl chlorides.

Trisubstituted vinylphosphonates have been prepared via three-component reaction using phosphites, acetylenic esters, and aroyl chlorides in good yields. A variety of phosphites, activated acetylenes, and aroyl chlorides have been successfully employed in these reactions. In addition, three-component synthesis of vinylphosphonate provides exclusive E-olefin stereochemistry.

Recyclization of 2-Iminochromenes via Ketene Aminal Intermediates: One-Pot, Three-Component Reaction for Synthesis of 1,4-Dihydropyridines-fused-1,3-diazaheterocycles

Abstract An efficient, one-pot synthesis of 4-aryl-1,4-dihyropyrido[1,2-a]-fused-1,3-diazaheterocycles by three-component reaction of 1,n-diamine, nitroketene dithioacetal (1,1-di(methylthio)-2-nitroethene), and 2-iminochromenes in EtOH is reported. This new protocol has the advantages of good yields, short reaction times, and convenient operation. The structures were corroborated spectroscopically (infrared, 1H and 13C NMR, and electron impact–mass spectrometry) and by elemental analyses. A plausible mechanism for this type of recyclization is proposed. Supplemental materials are available for this article. Go to the publishers online edition of Synthetic Communications® to view the free supplemental file. GRAPHICAL ABSTRACT

Two different 2,2′-bipyridine cadmium(II) perchlorate complexes, [Cd(2,2′-bipy)2(H2O)(ClO4)]ClO4 and [Cd(2,2′-bipy)3](ClO4)2 ·0.5 2,2′-bipy, syntheses, characterization, thermal and structural studies

Reactions of 2,2′-bipyridine (2,2′-bipy) with cadmium perchlorate in a ratio of M : L 1 : 2 and 1 : 3 give complexes with stoichiometry [Cd(2,2′-bipy)2(H2O)(ClO4)]ClO4 (1) and [Cd(2,2′-bipy)3](ClO4)2 · 0.5 2,2′-bipy (2), respectively. The new complexes were characterized by elemental analyses and IR-, 1H-, 13C-NMR spectroscopy. The crystal structures of the [Cd(2,2′-bipy)2(H2O)(ClO4)]ClO4 (1) and [Cd(2,2′-bipy)3](ClO4)2 · 0.5 2,2′-bipy (2) were determined by X-ray crystallography and the their thermal behavior studied by TG and DTA. Complexes 1 and 2 are built up of monomeric [Cd(2,2′-bipy)2(H2O)(ClO4)]ClO4 and [Cd(2,2′-bipy)3](ClO4)2 · 0.5 2,2′-bipy with Cd2+ coordination, CdN4OwaterOperchlorate and CdN6, respectively. There are classical O–H ··· Operchlorate hydrogen bonds in complex 1 and non-classical C–H ··· Operchlorate approaches in complex 2. The monomeric units of 1 and 2 grow into dimeric and one-dimensional units by packing via hydrogen bonding.

Regioselective Multicomponent Sequential Synthesis of Oxa-Aza[3.3.3]propellanes

A concise and efficient sequential four-component approach to oxa-aza[3.3.3]propellanes has been developed by reaction of aryl isothiocyanates, malonate compounds, ninhydrin, and malononitrile in the presence of NaH in DMF. The value of this method lies in its regioselectivity, good yields, lack of a metal-catalyst, ease of handling, and creating five new bonds in one operation. No inert atmosphere or separation by column chromatography is necessary.

A 2-D polymer constructed through bridging acetate, hydroxo, aqua and bipyridine ligands: crystal structure of {[Cu2(μ-CH3COO)(μ-OH)(μ-H2O)(4,4′-bipy)](2H2O)(SiF6)}n

Abstract A novel 2-D coordination polymer constructed by μ2-acetate-O,O′, μ2-hydroxo, μ2-aqua and 4,4′-bipyridine (bipy) ligands has been synthesized and structurally characterized. Linear 1-D chain built by bridged μ2-acetate-O,O′, μ2-hydroxo and μ2-aqua units is composed of Cu2O2 motifs and syn-anti bridged acetate ligands. The copper atom with a five-coordination has a distorted square-pyramidal geometry completed by two nitrogen atoms from 4,4′-bipyridine and three oxygen atoms from acetate, hydroxo and water ligands. The strong stacking effect is observed between 4,4′-bipyridine ligands.

Effects of phosphorus and chilling under low irradiance on photosynthesis and growth of tomato plants.

To determine the effects of phosphorus nutrition on chilling tolerance of photosynthetic apparatus, tomato (Lycopersicon esculentum Mill. cv. Kenfengxin 2002) plants were raised under different P contents and subjected to 7 d of chilling at 9/7 °C. After chilling (2 h or 7 d) plant growth, P content in tissue, gas exchange and chlorophyll fluorescence were measured. Decreasing P concentration [P] in the nutrient solution markedly reduced plant growth and the chilled plants exhibiting higher optimum [P] than the unchilled plants. Decreasing [P] significantly decreased light saturated net photosynthetic rate (PNsat), maximum carboxylation velocity of Rubisco (Vcmax), maximum potential rate of electron transport contributed to Rubisco regeneration (Jmax), quantum efficiency of photosystem (PS) 2 (ΠPS2) and O2 sensitivity of PNsat (PSO2) and this trend was especially apparent in chilled plants.

CdII 4,4,4-trifluoro-1-phenyl-1,3-butandione complexes of 1,10-phenanthroline and 4,4′-bipyridine

Cadmium(II) 4,4,4-trifluoro-1-phenyl-1,3-butandione (HTFPB) complexes of 1,10-phenanthroline (phen) and 4,4′-bipyridine (4,4′-bipy), Cd(L)(TFPB)2, have been synthesized and characterized by elemental analysis, IR-, 1H NMR spectroscopy and X-ray crystallography. The self-assembly of Cd(L)(TFPB)2 complexes, (L = phen or 4,4′-bipy) is caused by C–H ··· F–C, and π–π stacking interactions.