Synthesis of Canthin-4-ones and Isocanthin-4-ones via B Ring Construction.

Canthin-4-one is synthesized via a six-step procedure starting from commercially available 3-amino-4-bromopyridine in 26% overall yield. 3-Amino-4-bromopyridine is initially converted to 8-bromo-1,5-naphthyridin-4(1)-one. O-Methylation, intermolecular Pd-catalyzed C-C coupling, and demethylation afford the key intermediate, 8-(2-chlorophenyl)-1,5-naphthyridin-4(1)-one, for which intramolecular C-N coupling completes the synthesis of the canthin-4-one skeleton.

Catalysis of a Diels-Alder Reaction between Azachalcones and Cyclopentadiene by a Recyclable Copper(II)-PEIP Metal-Organic Framework.

Metal-organic frameworks (MOFs) have attracted considerable interest as emerging heterogeneous catalysts for organic transformations of synthetic utility. Herein, a Lewis-acidic MOF, {[Cu(PEIP)(5-NH-BDC)(DMF)]·7DMF}∞, denoted as Cu(ΙΙ)-PEIP, has been synthesized via a one-pot process and deployed as an efficient heterogeneous catalyst for a Diels-Alder cycloaddition. Specifically, the [4 + 2] cycloaddition of 13 substituted azachalcone dienophiles with cyclopentadiene has been investigated.

Novel Co and Ni Metal Complexes and Ferromagnets by the Combination of 2-Pyridyl Oximes with Polycarboxylic Ligands.

The use of 2-pyridyl oximes in metal complexes chemistry has been extensively investigated in the last few decades as a fruitful source of species with interesting magnetic properties. In this work, the initial combination of pyridine-2-amidoxime (pyaoxH) and 2-methyl pyridyl ketoxime (mpkoH) with isonicotinic acid (HINA) and 3,5-pyrazole dicarboxylic acid (Hpdc) has provided access to three new compounds, [Ni(INA)(pyaox)(pyaoxH)(DMF)] (), [Co(mpko)(mpkoH)(OMe)(HO)](ClO) (), and [Co(OH)(Hpdc)(Hpdc)] (). displays a square-planar metal topology, being the first example that bears simultaneously HINA and pyaoxH in their neutral or ionic form.

8,8'-(Benzo[][1,2,5]thiadiazole-4,7-diyl)bis(quinolin-4(1)-one): a twisted photosensitizer with AIE properties.

A new benzothiadiazole (BTZ) luminogen is prepared the Suzuki-Miyaura Pd-catalysed C-C cross-coupling of 8-iodoquinolin-4(1)-one and a BTZ bispinacol boronic ester. The rapid reaction (5 min) affords the air-, thermo-, and photostable product in 97% yield as a yellow precipitate that can be isolated by filtration. The luminogen exhibits aggregated-induced emission (AIE) properties, which are attributed to its photoactive BTZ core and nonplanar geometry.

First Synthesis of the Inherently Chiral Trans-4' Bisadduct of C N Azafullerene by Using Cyclo-[2]-dodecylmalonate as a Tether.

The multiaddition chemistry of azafullerene C N has been scarcely explored, and the isolation of pure bisadducts is in its infancy. Encouraged by the recent regioselective synthesis of the inherently chiral equatorial bisadduct of C N, we focused on the isolation of the first trans-4 bisadduct in a simple two-step approach. The first regioselective synthesis of the trans-4 bisadduct of C N by using cyclo-[2]-dodecylmalonate as a tether is now reported.

Synthesis and Chemistry of Benzo[][1,2,6]thiadiazino[3,4-][1,4]diazepin-10(11)-ones and Related Ring Transformations.

2-[(3,5-Dichloro-4-1,2,6-thiadiazin-4-ylidene)amino]benzamides are cyclized to benzo[][1,2,6]thiadiazino[3,4-][1,4]diazepin-10(11)-ones via (i) treatment with NaH and via (ii) Pd-catalyzed C-N coupling. The behavior of the latter toward nucleophiles and thermal, oxidative, and reductive conditions revealed unexpected transformations to 3,5-dioxo-4,5-dihydro-3-benzo[][1,4]diazepine-2-carbonitrile and 2-(4-substituted-1,2,5-thiadiazol-3-yl)quinazolin-4(3)-ones.

Tether-Directed Regioselective Synthesis of an Equatorial Bisadduct of Azafullerene Using Cyclo-[2]-octylmalonate.

Bisazafullerene (C N) has been functionalized under aerobic conditions with cyclo-[2]-octylmalonate through a Mannich-type reaction, furnishing the corresponding monoadduct. A regioselective tether-directed Bingel cyclopropanation reaction was then carried out on the azafullerene core to yield a single bisadduct. Spectroscopic analysis of the formed bisadduct showed it to have a C symmetrical structure, making it inherently chiral.

Redox Active Quinoidal 1,2,4-Benzotriazines.

Modifying the para-quinonimine 1,3-diphenyl-1,2,4-benzotriazin-7(1 H)-one (2a) ( E -1.20 V), by replacing the N1-phenyl by pentafluorophenyl, the C3-phenyl by trifluoromethyl, or the C7 carbonyl by ylidenemalononitrile, led to improved electron affinities as determined by cyclic voltammetry and computational studies. Combining structural changes further improved electron accepting abilities: the most electron deficient analogues ( E ∼ -0.

Synthesis and Characterization of Isodiphenylfluorindone and Isodiphenylfluorindinone.

Isodiphenylfluorindone 6 and isodiphenylfluorindinone 7 are synthesized. The former reacts with NaOMe to give the 13-methoxyisodiphenylfluorindone 22 (95%), while the latter reacts with 70% perchloric acid to give the bisperchlorate 21 (87%) and with MnO dimerizes to give 13,13'-bi(isodiphenylfluorindone) 4 (60%). UV-vis, NMR, CV, and DFT computational studies support the structural assignments of all products.

Stepwise synthesis, characterization, DNA binding properties and cytotoxicity of diruthenium oligopyridine compounds conjugated with peptides.

Although the interactions of oligopyridine ruthenium complexes with DNA have been widely studied, the biological activity of similar diruthenium oligopyridine complexes conjugated with peptides has not been investigated. Herein, we report the stepwise synthesis and characterization of diruthenium complexes with the general formula [(L)Ru(tppz)Ru(L)] (tppz = 2,3,5,6-tetra(2-pyridyl)pyrazine, L = 2,2':6',2''-terpyridine or 4-phenyl-2,2':6',2''-terpyridine and L = 2,2':6',2''-terpyridine-4'-CO(Gly-Gly-Gly-LysCONH) (5), (6), n = 5; 2,2':6',2''-terpyridine-4'-CO(Gly-Gly-Lys-LysCONH) (7), (8), n = 6; 2,2':6',2''-terpyridine-4'-CO(Ahx-LysLysCONH) (9), (10), n = 5, Ahx = 6-aminohexanoic acid). The compounds [(trpy)Ru(tppz)Ru(trpy-COH)](PF), (2)(PF), [(ptrpy)Ru(tppz)Ru(trpy-COH)](PF), (3)(PF) and [(ptrpy)Ru(tppz)Ru(trpy)](PF), (4)(PF) were also characterized by single crystal X-ray methods.

Oxidation of Isodiphenylfluorindine: Routes to 13-Oxoisodiphenylfluorindinium Perchlorate and Fluorindine Cruciform Dimers.

Isodiphenylfluorindine (5) reacts with KCrO/H to give 13-oxoisodiphenylfluorindinium perchlorate (7) (75%), but with phenyliodine bis(trifluoroacetate) (PIFA) or MnO it gives the zwitterionic and quinoidal cruciform 13,13'-dimers 11 (85%) and 12 (89%), respectively. The zwitterionic 13,13'-dimer 11 can be rapidly converted with MnO into the quinoidal 13,13'-dimer 12 (100%). UV-vis, NMR, single-crystal X-ray diffraction, and density functional theory studies support the structural assignments of all products.

Reticular Chemistry and the Discovery of a New Family of Rare Earth (4, 8)-Connected Metal-Organic Frameworks with csq Topology Based on RE(μ-O)(COO) Clusters.

In recent years, the design and discovery of new metal-organic framework (MOF) platforms with distinct structural features and tunable chemical composition has remarkably enhanced by applying reticular chemistry rules and the molecular building block (MBB) approach. We targeted the synthesis of new rare earth (RE)-MOF platforms based on a rectangular-shaped 4-c linker, acting as a rigid organic MBB. Accordingly, we designed and synthesized the organic ligand 1,2,4,5-tetrakis(4-carboxyphenyl)-3,6-dimethyl-benzene (HL), in which the two methyl groups attached to the central phenyl ring lock the four peripheral carboxyphenyl groups to an orthogonal/vertical position.

Preparation of Blatter Radicals via Aza-Wittig Chemistry: The Reaction of N-Aryliminophosphoranes with 1-(Het)aroyl-2-aryldiazenes.

Reacting N-aryliminophosphoranes with 1-(het)aroyl-2-aryldiazenes in preheated diphenyl ether at ca. 150-250 °C for 5-25 min affords in most cases the 1,3-diaryl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yls (aka Blatter radicals) in moderate to good yields. All new compounds are fully characterized, including EPR and CV studies for the radicals.

Synthesis, reactivity and characterization of Pt(ii) complexes with N,N' chelating ligands; structure and dimethylsulfoxide reactivity relationship.

Platinum(ii) complexes of the formula PtLCl [L = 2-(2'-pyridyl)quinoxaline, (pqx) (1), 2,(2'-pyridyl)benzo[g]quinoxaline, (pbqx) (3) and 2,(2'-pyridyl)quinoline, (pqn) (5)] were synthesized and characterized by spectroscopic and X-ray diffraction methods. Also, monodentate coordination of the ligands pqx and pbqx formed the complexes trans-Pt(DMSO)pqxCl (2) and trans-Pt(DMSO)pbqxCl (4) as it is indicated from X-ray crystal structure and NMR studies. The reaction of the complexes (1), (3) and (5) with DMSO-d revealed a ligand-release solvolysis, which was studied by means of NMR techniques.

The Acid and/or Thermal Mediated Ring Contraction of 4H-1,2,6-Thiadiazines To Afford 1,2,5-Thiadiazoles.

A near-quantitative acid and/or thermal mediated ring contraction of 3',5'-diarylspiro(benzo[d][1,3]dioxole-2,4'-[1,2,6]thiadiazines) affords 3-aryl-4-(2-arylbenzo[d][1,3]dioxol-2-yl)-1,2,5-thiadiazoles. The reaction scope was studied providing 11 examples of this ring contraction. A double Wagner-Meerwein reaction mechanism is proposed.