The pyrolysis of 3-oxa-11-chloro-eicosafluoroundecane sulfinate and sulfonate salts

The thermal decomposition of sodium 3-oxa-11-chloro-eicosafluoroundecane sulfinate (1) and potassium 3-oxa-11-chloroeicosafluoroundecane sulfonate (2) were studied. 7-Chlorotridecafluoroheptene-1 (3), 1-hydro-7-chloro-tetradecafluoroheptane (4), 1-hydro-3-oxa-11-chloro-eicosafluoroundecane (5), methyl 8-chloro-tetradecafluorooctanate (6), and methyl 3-oxa-11 - chloro - octadecafluoroundecanate (7) were isolated and characterized when compound 1 was pyrolyzed and then reacted with methanol. However, only 8-chloro-tetradecafluorooctanoic acid and its methyl ester were obtained in high yield when compound 2 was subjected to pyrolysis. A possible mechanism was proposed.     

Proximity effects in 1-azaspirocyclo[5.5]undecanes. X-ray structure determination of a diol derivative

Neighbouring group participation is used to control bromination of the alkene (1) to give the bromo-acetate (3) which is converted into the diol (6a) [characterised by X-ray structure determination of the cyclic carbamate (8)] and the epoxide (2).     

New benzimidazole derivatives: Design,synthesis, docking,and biological evaluation

The aim of this study was to synthesize novel enaminonitrile derivatives starting from 2-aminobenzimidazole and utilize this derivative for the preparation of novel heterocyclic compounds and assess their function for biological activity screening. The key precursor N-(1H-benzo[d]imidazol-2-yl)carbonohydrazonoyl dicyanide (2) was prepared in pyridine by coupling of diazotized 2-aminobenzimidazole (1) with malononitrile. Compound 2 was subjected to react with various secondary amines such as piperidine, morpholine, piperazine, diphenylamine, N-methylglucamine, and diethanolamine in boiling ethanol to give the acrylonitriles (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(piperidin-1-yl)acrylonitrile (3), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-morpholinoacrylonitrile (4), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(piperazin-1-yl)acrylonitrile (5), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(diphenylamino)acrylonitrile (6), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(methyl((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)acrylonitrile (7), and (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(bis(2-hydroxyethyl)amino)acrylonitrile (8), respectively. It has been found that the behaviour of nitrile derivative 2 towards hydrazine hydrate to the creation of 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-1H-pyrazole-3,5-diamine (9). The reaction of malononitrile with compound 2 in an ethanolic solution catalyzed with sodium ethoxide afforded 4-amino-1-(1H-benzo[d]imidazol-2-yl)-6-imino-1,6-dihydropyridazine-3,5-dicarbonitrile (11). Moreover, malononitrile reacted with 7 in a boiling ethanolic sodium ethoxide solution to give 2-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-4-amino-6-(methyl((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)pyrimidin-2-yl)acetonitrile (14). Heating 7 in boiling acetic anhydride and pyridine afforded (2R,3R,4R,5S)-6-(((1E)-2-((1-acetyl-1H-benzo[d]imidazol-2-yl)diazenyl)-1-(N-acetylacetamido)-2-cyanovinyl)(methyl)amino)hexane-1,2,3,4,5-pentayl pentaacetate (15). When compound 15 is heated for a long time in refluxing DMF including a catalytic of TEA, cyclization occurs to give the corresponding (2R,3R,4R,5S)-6-((1-acetyl-3-((1-acetyl-1H-benzo[d]imidazol-2-yl)diazenyl)-4-amino-6-oxo-1,6-dihydropyridin-2-yl)(methyl)amino)hexane-1,2,3,4,5-pentayl pentaacetate (16). In addition, triethyl orthoformate was reacted with compound 7 in the presence of acetic anhydride to afford the corresponding ethoxymethyleneamino derivative (2R,3R,4R,5S)-6-(((1E)-2-((1-acetyl-1H-benzo[d]imidazol-2-yl)diazenyl)-2-cyano-1-(((E) ethoxymethylene)amino)vinyl)(methyl)amino)hexane-1,2,3,4,5-pentayl pentaacetate (17). Also, it has been found that heating a mixture of 7 with DMF/DMA in anhydrous xylene yielded compound (1E)-N'-((1E)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-cyano-1-(methyl((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)vinyl)-N,N-dimethylformimidamide (18). In addition, compound 7, when reacted with several acid anhydrides, allowed the matching phthalimide derivatives 19–26. The results showed that compound 14 has significantly higher ABTS and antitumor activities than the other compounds. Molecular modelling was also studied for compounds 22 and 24. The viability of four many cell lines—the African green monkey kidney epithelial cells (VERO), human breast adenocarcinoma cell line (MCF-7), human lung fibroblast cell line (WI-38), and human hepatocellular liver carcinoma cell line (HepG2) was examined to determine the antitumor activities of the newly synthesized compounds. Also, it was found that compounds 9, 11, 15, 16, 22, 23, 24 and 25 are strong against HepG2 cell lines, while 16, 22, and 25 are strong against WI-38 cell lines. Moreover, it was also found that compounds 16 and 22 are strong against VERO cell lines. On the other hand, compounds 7, 14, 15, 16, and 22 are strong while the rest of the other compounds are moderate against the MCF-7 cell line. The result of docking showed that compound 24 got stabilized inside the pocket with a very promising binding score of ? 8.12 through hydrogen bonds with Arg184 and Lys179, respectively.     

Isolation and X-ray structure determination of Ru4(CO)12(C6H6O), a precatalyst for the transfer hydrogenation of cyclohex-1-en-2-one

Ru₄(CO)₁₂(C₆H₆O) (1) and Ru₃(CO)₁₀(C₆H₈O) (2) have been obtained from the reaction of Ru₃(CO)₁₂ with cyclohex-1-en-2-one; 1 has been characterized by an X-ray structure determination. Both 1 and 2 have been found to be active precatalysts for the transfer hydrogenation of cyclohex-1-en-2-one.     

Electropolymerization of [Ru(bpy)(CO)2Cl2] (bpy=2,2′-bipyridine: a revisited trans versus cis(Cl) isomeric influence study

The mono-bipyridine bis carbonyl complex [Ru(bpy)(CO)₂Cl₂] exists in two stereoisomeric forms having a trans(Cl)/cis(CO) (1) and cis(Cl)/cis(CO) (2) configuration. In previous work we reported that only the trans(Cl)/cis(CO) isomer 1 leads by a two-electron reduction to the formation of [Ru(bpy)(CO)₂]_n polymeric film on an electrode surface. This initial statement was overstated, as both isomers allowed the build up of polymers. A detailed comparison of the electropolymerization of both isomers is reported here, as well as the reduction into dimers of parent stereoisomer [Ru(bpy)(CO)₂(C(O)OMe)Cl] complexes 3 and 4 obtained as side products during the synthesis of 1 and 2.     

[Mn18]2+ and [Mn21]4+ single-molecule magnets

The synthesis and structural characterization of the two new Mn complexes [Mn₁₈O₁₄(O₂CMe)₁₈(hep)₄(hepH)₂(H₂O)₂](ClO₄)₂ (1) and [Mn₂₁O₁₆(O₂CMe)₁₆(hmp)₆(hmpH)₂(pic)₂(py)(H₂O)](ClO₄)₄ (3) are presented, together with a detailed study of their magnetic properties. Complex 1 possesses a ground-state spin of S=13, and the ground-state spin for 3 is estimated to be S=17/2 or 19/2. Both complexes 1 and 3 are new examples of single-molecule magnets (SMMs), displaying frequency-dependent out-of-phase AC signals, as well as magnetization vs. DC field hysteresis at temperatures below 1 K. Complex 1 straddles the classical/quantum interface by also displaying quantum tunneling of the magnetization (QTM).     

New Ru3(CO)12 derivatives with bulky diphosphine ligands: synthesis,structure and catalytic potential for olefin hydroformylation

The diphosphine clusters Ru₃(CO)₁₀(dcpm) (1) and Ru₃(CO)₁₀(F-dppe) (2) as well as the bis(diphosphine) clusters Ru₃(CO)₈(dcpm)₂ (3) and Ru₃(CO)₈(F-dppe)₂ (4) have been synthesised from Ru₃(CO)₁₂ and the bulky diphosphines 1,2-bis[bis(pentafluorophenyl)phosphino]ethane (F-dppe) and bis(dicyclohexylphosphino)methane (dcpm). While the single-crystal X-ray structure analyses of 1, 2 and 3 show the expected μ₂-η² coordination of the diphosphine ligands, that of 4 reveals an unusual structure with one μ₂-η²-diphosphine and one μ₁-η²-diphosphine ligand. The clusters 1–4 catalyse the hydroformylation of ethylene and propylene to give the corresponding aldehydes, 2 showing higher activities than those observed for Ru₃(CO)₁₂ and Ru₃(CO)₁₀(dppe).     

Sequential directed ortho metalation reactions. A synthesis ofanthramycin.

The pyrrolo[1,4]benzodiazepine 2 (R = ME), a key intermediate in the synthesis of anthramycin (1), has been prepared via a new approach involving two sequential directed ortho metalation reactions (4) and a previously unreported isatoic anhydride construction (8 → 9).     

Synthesis and characterisation of linked triosmium clusters using the bis(diphenylphosphino)acetylene ligand

The reaction of Os₃(CO)₁₁(NCMe) with bis(diphenylphosphino)acetylene (dppa) at room temperature affords [Os₃(CO)₁₁]₂(dppa) (1) in good yield, while Os₃(CO)₁₀(NCMe)₂ with an excess of dppa gives [Os₃(CO)₁₀(dppa)]₃ (2) and [Os₃(CO)₁₀(dppa)]₄ (3) in moderate yields. The structure of 1 has been determined by a single crystal X-ray diffraction study.     

Hydrothermal synthesis and crystal structure of two luminescent three-dimensional supramolecular complexes generated from mixed ligands

Two 3D metal-organic supramolecular complexes [Zn₂(btec)(2, 2′-bpy)₂(H₂O)₂] (1), [Cd₂(dpa)₂(phen)₂(H₂O)₂] (2) have been prepared by hydrothermal reaction and characterized by IR and single-crystal X-ray diffraction analysis. The 3D architectures of 1 and 2 both possess rectangular cavities. Furthermore, compounds 1 and 2 both show intense photoluminescent properties at room temperature.     

Photochemical reactivity of Os3(CO)12 and thermal activation of diosmacyclobutanes towards alkynes

Long wavelength photolysis of Os₃(CO)₁₂ and MeO₂CCCCO₂Me (DMAD) in benzene gives, as isolable products, Os₂(CO)₈(μ-η¹,η¹-DMAD) (4a) and Os₂(CO)₆(DMAD)₄ (5). Structural work confirms the diosmacyclobutene arrangement in 4a and reveals a unique coupling of alkynes in 5. The potentially more general thermal reaction between preformed diosmacyclobutane and alkynes gives improved yields of 4a and allows the isolation, albeit in low yield, of Os₂(CO)₈(μ-η¹,η¹-CF₃CCCF₃) (4b).     

Six novel complexes based on 5-Acetoxy-1-(6-chloro-pyridin-2-yl)-1H-pyrazole-3-carboxylic acid methyl ester derivatives: Syntheses,crystal structures,and anti-cancer activity

A novel 5-Acetoxy-1-(6-chloropyridin-2-yl)-1H-pyrazole-3-carboxylic acid methyl ester derivatives Htcdodtta (1), and it’s five complexes, [Cu₂(L¹)₂]·(CH₃CN) (2), [Cu₂(L²)_1.63(L³)_0.37]·(CH₃OH)_0.5 (3), [Cu₂(L³)(L⁴)]·(C₂H₅OH)_0.5·(CH₃OH)_0.5 (4), [Cu₂(L⁴)(L⁵)]·(H₂O) (5) and [Cu₂(L¹)_1.18(L²)_0.82] (6) have been synthesized. The Htcdodtta, HL¹-HL⁵ were formed in-situ reaction. HL¹-HL⁵ are homologues which possess two chiral carbons. Compounds 1–6 were characterized using single-crystal X-ray diffraction, IR, and elemental analysis. Compounds 2–6 are dinuclear copper complexes. The in vitro cytotoxicities of compounds 1–4 against a variety of cell lines were evaluated by MTT assays. Hela cancer cell apoptosis assay of 1 and 2 were examined by flow cytometry. The cell apoptosis in NP69, A549, Capan-2, Hela, HepG2, and HUVECs cell lines induced by compound 2 was further affirmed by cellular morphology observations.     

Studies on the reactivity of the clusters [Ru3(CO)8(μ-H)2(μ-PR2)2] (R=But,Cy) towards phosphine ligands

The reaction behavior of the 48e-clusters [Ru₃(CO)₈(μ-H)₂(μ-PR₂)₂] (R=Bu^t, 1a; R=Cy, 1b) towards phosphine ligands has been studied. Whereas 1a reacts spontaneously with many phosphines at room temperature, a lack of reactivity for 1b under similar conditions is observed. Thus 1a reacts with dppm (Ph₂PCH₂PPh₂) to the known 46e-cluster [Ru₃(μ-CO)(CO)₄(μ₃-H)(μ-H)(μ-PBu^t₂)₂(μ-dppm)] (2a), and the reaction of 1a with dppe (Ph₂PC₂H₄PPh₂) yields analogously [Ru₃(μ-CO)(CO)₄(μ₃-H)(μ-H)(μ-PBu^t₂)₂(μ-dppe)] (3). Reactions of 1a with dmpm (Me₂PCH₂PMe₂), dmpe (Me₂PC₂H₄PMe₂) and PBuⁿ₃, respectively, gave in each case a mixture of products which could not be characterized. Contrary to the reaction behavior at room temperature, 1b reacts with phosphines in THF under reflux yielding the novel complexes [Ru₃(CO)₆(μ-H)₂(μ-PCy₂)₂L₂] (L=Cy₂PH, 4a; L=Bu^t₂PH, 4b; L=Ph₂PH, 4c; L=P(OEt)₃, 4d). 4a is also obtained directly by the reaction of [Ru₃(CO)₁₂] with an excess of Cy₂PH. The molecular structure of 4a has been determined by a single-crystal X-ray analysis. Moreover, the thermolysis of 1a in octane affords [Ru₃(CO)₈(μ-H)₂(μ₃-PBu^t)(Bu^t₂PH)] (6) as the main product, and the thermolysis of [Ru₃(CO)₉(Bu^t₂PH)(μ-dppm)] (7) yields 2a to a considerable extent. Treatment of 1a with carbon tetrachloride leads to [Ru₃(CO)₇(μ-H)(μ-PBu^t₂)₂(μ-Cl)] (8) as the main product.     

2,5,5-Trimethyl-2-oxazolin-4-one,its perchlorate,and α-acetoxyisobutyronitrile by acetylation of acetone cyanohydrin

Acetone cyanohydrin (1) yields on acylation and ring closure with anhydrides and perchloric acid. 2-oxazolin-4-onium perchlorates 5a, 5c or 5d. The same perchlorates (5a, 5b) may be obtained under similar conditions from acyloxy-nitriles (2) or -amides (4). Perchlorates 5 may be deprotonated in pyridine to 2-oxazolin-4-ones (6), but in aqueous solution they undergo ring opening to acyloxy-amides 4a.c.d. or to N-benzoyl-α-hydroxy-isobutyramide 7b.     

Hetero- and homo-nuclear bimetallic ruthenol complexes by dehydrogenative metallacyclization of Ru(CO)3(bi-1,7-cyclooctadienyl), preparation and x-ray structure of Fe(CO)3(C16H22), RuFe(CO)6(C16H22) and Ru2(CO)6(C16H20)

The reaction of M₃(CO)₁₂ (M = Ru, Fe) with excess bi-2,7-cyclooctadienyl (C₁₆H₂₂) 1 gave a mononuclear complex M(CO)₃(1,2,1′-2′-η⁴-C₁₆H₂₂), 2a (M = Ru) or 3a (M = Fe), in good yield. Treatment of 2a with Fe₃(CO)₁₂ or reaction of 3a with Ru₃(CO)₁₂ gave the heterobimetallic complex RuFe(CO)₆(C₁₀H₂₂) consisting of a ruthenacyclopentadiene unit coordinated to an Fe(CO)₃ fragment, as confirmed by ¹H NMR and X-ray studies. The corresponding homobimetallic complex Ru₂(CO)₆(C₁₆H₂₂) was obtained from the 1:1 reaction of 2a with Ru₃(CO)₁₂, while the direct reaction of 1 with Ru₃(CO)₁₂ gave Ru₂(CO)₆(C₁₆H₂₀) preferentially with a loss of two hydrogen atoms. The pathway for formation of these bimetallic complexes was interpreted as a dehydrogenative metallacyclization followed by hydrogen transfer.     

A new approach to synthesis of α-nitronyl nitroxide carboxylates. First metal complexes with α-imino nitroxide carboxylate

An effective procedure has been developed for the synthesis of the potassium salt of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl-3-oxide-2-carboxylic acid K(1). The salts of 4,4,5,5-tetramethyl-1-oxyl-4,5-dihydro-1H-imidazole-2-carboxylic acid X(2) are kinetically much more stable than K(1). Due to this, a series of heterospin complexes Cu(2)₂(CH₃OH)₂, Cu(2)₂(H₂O)₂, Cu(2)₂, Co(2)₂(CH₃OH)₂, Ni(2)₂(H₂O)₂, Ni(2)₂(py)₂, and Ni(2)₂(dipy) · H₂O were isolated. For K(2), Cu(2)₂(CH₃OH)₂, and Ni(2)₂(py)₂, crystal and molecular structure has been determined. For Cu(2)₂ and Ni(2)₂(bipy), cooperative magnetic ordering has been recorded at 16.6 and 4.6 K, respectively.     

Hypocholesterolemic agent compactin. an alternative diels-alder strategy for the synthesis of the hexahydronaphthalene portion

The synthesis of the hexahydronaphthalene segment (4) of compactin (1) has been accomplished in a short sequence (8 steps from 9) featuring the intramolecular Diels-Alder cycloaddition of 7b.     

Dinuclear ruthenium(I) complexes of the type [Ru2(CO)4L2] with carboxylate or 2-pyridonate ligands: Evaluation as catalysts for olefin cyclopropanation with diazoacetates

Dinuclear ruthenium(I,I) carboxylate complexes [Ru₂(CO)₄(μ-OOCR)₂]_n (R = CH₃ (1a), C₃H₇ (1b), H (1c), CF₃ (1d)) and 2-pyridonate complex [Ru₂(CO)₄(μ-2-pyridonate)₂]_n (3) catalyze efficiently the cyclopropanation of alkenes with methyl diazoacetate. High yields are obtained with terminal nucleophilic alkenes (styrene, ethyl vinyl ether, α-methylstyrene), medium yields with 1-hexene, cyclohexene, 4,5-dihydrofuran and 2-methyl-2-butene. The E-selectivity of the cyclopropanes obtained from the monosubstituted alkenes and the cycloalkenes decreases in the order 1b > 1a > 1d > 1c. The cyclopropanation of 2-methyl-2-butene is highly syn-selective. Several complexes of the type [Ru₂(CO)₄(μ-L¹)₂]₂ (4) and (5), [Ru₂(CO)₄(μ-L¹)₂L²] (L² = CH₃OH, PPh₃) (6)–(9) and [Ru₂(CO)₄(CH₃CN)₂(μ-L¹)₂] (10) and (11), where L¹ is a 6-chloro- or 6-bromo-2-pyridonate ligand, are also efficient catalysts. Compared with catalyst 3, a halogen substituent at the pyridonate ligand affects the diastereoselectivity of cyclopropanation only slightly.     

Interpenetrating and non-interpenetrating 3-dimensional coordination polymer frameworks from multiple building blocks

Reaction of Co(NO₃)₂6H₂O with the multidentate ligands benzene-1,3,5-tricarboxylate (btc) and the flexible bipyridyl ligand 1,2-bis(4-pyridyl)ethane (bpe) affords the 3-dimensional coordination polymers [Co₃(btc)₂(bpe)₃(eg)₂](guests) 1, where eg = ethylene glycol, and [Co₂(Hbtc)₂(bpe)₂](bpe) 2. Both phases are comprised of infinite metal-carboxylate dimer chains, linked into 2-dimensional sheets by the bpe ligands. These sheets are further linked to adjacent sheets through covalent interactions, 1, or through hydrogen-bonding interactions, 2, to yield the 3-dimensional structures. Phase 1 exhibits solvent filled 1-dimensional pores, whereas 2 is triply-interpenetrated to form a dense solid array.     

Synthesis and antimicrobial screening of 1,3,4-oxadiazole and clubbed thiophene derivatives

In the present study, a novel series of 2-{5-[4-(1-aza-2-(2-thienyl)vinyl)phenyl](1,3,4-oxadiazol-2-ylthio)}-N-arylacetamides (IV)_1–12 were synthesized and tested for their antimicrobial activity. Newly synthesized compounds were screened for their antibacterial and antifungal activities on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Staphylococcus pyogenes, Candida albicans, Aspergillus niger and Aspergillus clavatus. The chemical structures of newly synthesized compounds were elicited by IR, ¹H NMR, ¹³C NMR and mass spectral data. The synthesized bio-active compounds exhibited excellent to moderate antimicrobial activity. Compounds (IV)₅, (IV)₆ and (IV)₇ possess excellent antibacterial activity whereas compounds (IV)₆, (IV)₉ and (IV)₁₁ possess excellent antifungal activity.