Influence of the steric properties of pyridine ligands on the structure of complexes containing the {LnCd2(bzo)7} fragment

The reaction of Cd(NO₃)₂ · 4H₂O and Eu(NO₃)₃ · 6H₂O or Tb(NO₃)₃ · 6H₂O with potassium 3,5-di-tert-butylbenzoate (Kbzo) and N-donor ligands (1,10-phenanthroline (phen), 2,4-lutidine (2,4-lut), 3,4-lutidine (3,4-lut), phenanthridine (phtd), 2,3-cyclododecenopyridine (cdpy), acridine (acr)) afforded heterometallic LnCd₂ complexes: [EuCd₂(bzo)₇(EtOH)₂(phen)] (2), [LnCd₂(bzo)₇(2,4-lut)₄] (Ln = Eu (3), Tb (4)), [EuCd₂(bzo)₇(H₂O)₂(2,4-lut)₂] · MeCN (5), [EuCd₂(NO₃)(bzo)₆(EtOH)₂(2,4-lut)₂] (6), [EuCd₂(bzo)₇(H₂O)(EtOH)(3,4-lut)₂] · 5EtOH (7), 3[EuCd₂(bzo)₇(H₂O)₂(phtd)₂] · 4phtd (8), [EuCd₂(bzo)₇(EtOH)₃(cdpy)] (9), 2[EuCd₂-(bzo)₂(EtOH)₄] · acr (10). The structures of complexes 2, 3, and 5–10 were determined by single-crystal X-ray diffraction. The isostructurality of complexes 3 and 4 was confirmed by powder X-ray diffraction. The structure of the trinuclear {Ln₂Cd} metal core is stable and independent of the type of peripheral ligands coordinated to cadmium atoms. Photoluminescent properties of compounds 3 and 4 were studied.

     

Isolation and antiproliferative activity of triterpenoids and fatty acids from the leaves and stem of Turraea vogelii Hook. f. ex benth

Chloroform extract from the leaves of Turraea vogelii Hook f. ex Benth demonstrated cytotoxic activity against a chronic myelogenous leukemia cell, K-562 with IC₅₀ of 14.27 μg/mL, while chloroform, ethyl acetate and methanol extracts from the stem of the plant inhibited K-562 cells growth with IC₅₀ of 19.50, 24.10 and 85.40 μg/mL respectively. Bioactive chloroform extract of Turraea vogelii leaves affords two triterpenoids: oleana-12,15,20-trien-3β-ol (1), and oleana-11,13-dien-3β,16α,28-triol (2), with six fatty esters, ethyl hexaeicos-5-enoate (3), 3-hydroxy-1,2,3-propanetriyltris(tetadecanoate) (4), 1,2,3-propanetriyl(7Z,7′Z,7′′Z)tris(-7-hexadecenoate) (5), 1,2,3-propanetriyl(5Z,5′Z,5′′Z)tris(-5-hexadecenoate) (6), 1,2,3-propanetriyltris(octadecanoate) (7), and 2β-hydroxymethyl tetraeicosanoate (8). Tetradecane (9), four fatty acids: hexadecanoic acid (10), tetradecanoic acid (11), (Z)-9-eicosenoic acid (12), and ethyl tetradec-7-enoate (13) were isolated from chloroform extract of Turraea vogelii stem. 1,2,3-propanetriyltris(heptadecanoate) (14), (Z)-9-octadecenoic acid (15) and (Z)-7-tetradecenoic acid (16) were isolated from ethyl acetate extract while (Z)-5-pentadecenoic acid (17) was obtained from methanol extract of the plant stem. Compounds 1, 2, 5, 6, 11, 12, 15, 16 and 17 exhibited pronounced antiproliferative activity against K-562 cell lines.     

Crystal structure and spectroscopic properties of polymeric adducts of the tetra-μ-haloaspirinate-dicopper(II)

Eight new copper(II) complexes with halo-aspirinate anions have been synthesized: [Cu₂(Fasp)₄(MeCN)₂]?·?2MeCN (1), [Cu₂(Clasp)₄(MeCN)₂]?·?2MeCN (2), [Cu₂(Brasp)₄(MeCN)₂]?·?2MeCN (3), {[Cu₂(Fasp)₄(Pyrz)]?·?2MeCN} _n (4), {[Cu₂(Clasp)₄(Pyrz)]?·?2MeCN} _n (5), [Cu₂(Brasp)₄(Pyrz)] _n (6), [Cu₂(Clasp)₄(4,4′-Bipy)] _n (7), and [Cu₂(Brasp)₄(4,4′-Bipy)] _n (8) (Fasp: fluor-aspirinate; Clasp: chloro-aspirinate; Brasp: bromo-aspirinate; MeCN: acetonitrile; Pyrz: pyrazine; 4,4′-Bipy: 4,4′-bipyridine). The crystal structure of two 2 and 4 have been determined by X-ray diffraction methods. All compounds have been studied employing elemental analysis, IR, and UV-Visible spectroscopic techniques. The results have been compared with previous data reported for complexes with similar structures.     

A Simple Approach to the Synthesis of Fluoren-9-Ones

Cyclohexene-l-Carboxylic acid (I) undergoes reaction with various aromatic substrates (2a-i) in presence of Polyphosphoric acid (PPA) at 100[ddot]c to give cis-1,2,3,4,4a,9a - hexahydrofluoren-9-ones (3a-i) in good yield. Dehydrogenation of (3a-i) with selenium powder afforded corresponding fluoren-9-ones (4a-i) in high yield.     

Reaction of the diiron toluenedithiolate hexacarbonyl complex with 1,1-bis(diphenylphosphino)methane

Reaction of [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₆ (1) with 1.5 equivalents of 1,1-bis(diphenylphosphino)methane (dppm) in toluene at reflux gave monosubstituted [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅(dppm) (2) and disubstituted [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₄(dppm)₂ (3) in 27 and 37% yields, respectively. Complexes 2 and 3 were characterized by elemental analysis, IR, NMR spectroscopy, and single crystal X-ray diffraction analysis.     

Reaction of Aryl and Heterocyclylhydrazines with 2-Methylchromone: Structural Investigation of the Products

Reaction of 2-methylchromone (2) with phenylhydrazine provides 3-methyl-5-(o-hydroxyphenyl)-1-phenylpyrazole (6) as a major product. In contrast under similar conditions, heterocyclylhydrazines (8a-c) yield exclusively 5-ethyl-3-(o-hydroxyphenyl)-1-heterocyclylpyrazoles (9a-c). The structural assignments are based on an unambiguous synthesis and an analysis of NMR (¹H & ¹³C) spectral data.     

Thermal study of cyclopalladated complexes of the type [Pd<Subscript>2</Subscript>(dmba)<Subscript>2</Subscript>X<Subscript>2</Subscript>(bpe)]

The synthesis, characterization and thermal analysis of the novel cyclometallated compounds [Pd₂(dmba)₂Cl₂(μ-bpe)] (1), [Pd₂(dmba)₂(N₃)₂(μ-bpe)] (2), [Pd₂(dmba)₂(NCO)₂(μ-bpe)] (3), [Pd₂(dmba)₂(SCN)₂(μ-bpe)] (4), [Pd₂(dmba)₂(NO₃)₂(μ-bpe)] (5) (bpe=trans-1,2-bis(4-pyridyl)ethylene; dmba=N,N-dimethylbenzylamine) are described. The thermal stability of [Pd₂(dmba)₂X₂(μ-bpe)] complexes varies in the sequence 1>4>3>2>5. The final residues of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction.     

A bulky oxime for the synthesis of Mn(III) clusters

The reaction between Mn(OAc)₂·4H₂O and Br-saoH₂ (=5-Br-salicylaldoxime) in EtOH in the presence of NMe₄OH led to the formation of the hexanuclear cluster [Mn₆O₂(Br-sao)₆(OAc)₂(H₂O)₂(EtOH)₂]·2.8H₂O·2.2EtOH (1). Switching from Mn(OAc)₂·4H₂O to Mn(ClO₄)₂·6H₂O, the same reaction upon addition of pivH (= trimethyl acetic acid) yielded [Mn₆O₂(Br-sao)₆(piv)₂(H₂O)₂(EtOH)₂]·6EtOH (2 6EtOH), and finally upon changing pivH to NaO₂CPh, we were able to isolate [Mn₆Na₂O₂(Br-sao)₆(O₂CPh)₄(H₂O)₂(EtOH)₄]·6EtOH (3 6EtOH). Clusters 1 and 2 6EtOH describe “typical” [Mn₆/oximate] complexes consisting of two {Mn₃} oxo-centered triangular units bridged by oximate groups, while in 3 6EtOH these triangular motifs are separated by two sodium cations. An investigation into the magnetic properties of all three clusters revealed the presence of dominant antiferromagnetic interactions, leading to ground states of S = 4 and 2 for 1 and 3, respectively. Finally, cluster 2 6EtOH functions as a single-molecule magnet with U_eff = 27.54 K.     

Polymer Intermediates and Polymers Derived from 5-t-Butyl-m-Xylene

Abstract

A series of condensation polymer intermediates, which included several new compositions, was prepared from 5-t-butyl-m-xylene (I) so that the effect of the bulky t-butyl group on polymer properties could be determined. Compound (I) was oxidized with nitric acid to obtain 5-t-butyl-isophthalic acid (II), which was converted successively to the diacid chloride, the diamide, the dinitrile, and finally to 5-t-butyl-m-xylene-α,α′-diamine (VI); the overall yield was 80%. The dimethyl ester of (II) was prepared and converted to 5-t-butyl-m-xylene-α,α′-diol (VIII), a new composition, in 79.5% overall yield; the diphenyl ester was also prepared. The sodium salt of (II) was catalytically reduced to obtain 5-t-butyl-1,3-cyclohexanedicarboxylic acid (IIa) in 95% yield. (IIa) was converted successively to the diacid chloride, the diamide, the dinitrile, and finally to 5-t-butyl-1,3-cyclohexanebis(methylamine) (VIa), a new composition; the overall yield was 37%. (IIa) was also converted to the dimethyl ester and finally to 5-t-butyl-1,3-cyclohexanedimethanol (VIIIa), a new composition; the overall yield was 64%. Condensation polymers were prepared from the intermediates (II), (IIa), (VI), (VIa), (VIII), and (VIIIa). These polymers had higher glass transition temperatures (T_g) than corresponding polymers containing no t-butyl groups. This general effect of the t-butyl group to increase the T_g value of the polymer was noted in all polymers prepared, regardless of whether the intermediate carrying the t-butyl group was a diacid, a diol, or a diamine, or whether the polymer was a polyamide, a polyester, or a polyurethane.     

A new isoquinoline alkaloid with anti-microbial properties from Berberis jaeschkeana Schneid. var. jaeschkeana

One new isoquinoline alkaloid named berberidione (1) along with four new source alkaloids berberine (2), palmatine (3), jatrorrhizine (4) and chondrofoline (5) and three new source non-alkaloids syringic acid (6), β-sitosterol (7) and stigmasterol (8) was isolated and characterised from different fractions of Berberis jaeschkeana Schneid var. jaeschkeana. All the structures were determined from 1D and 2D spectroscopic data. Crude extract, sub-fractions and isolated compounds showed excellent anti-microbial properties. The toxicity level for the alkaloids was found to be very low on THP-1 cells.     

Novel Synthesis of Pyrano[2,3-d]Thiazole,Thiazolo[3,2-a]Pyridine,and Pyrazolo [3′,4′:4,5] Thiazolo[3,2-a]Pyridine Derivatives

Cyclocondensation of 2-cyanomethyl-4-thiazolidinone (1) with tetracyanoethylene (2) furnished pyrano[2,3-d]thiazole derivative (4) . Benzo[e]pyrano[2,3-d]thiazole derivative (6) was obtained by cyclization of compound (1) with salicylaldehyde. In a similar manner, condensation of compound (1) with 2-hydroxy-1-naphthaldehyde in refluxing ethanol yielded naphtho[e]pyrano[2,3-d]thiazole derivative (7) . Interaction of compound (9) with benzylidenemalononitriles (10) (1 : 1 molar ratio) at reflux temperature in ethanol in the presence of piperidine afforded thiazolo[3,2-a]pyridines (12a-c) . Treatment of compound (12a) with hydrazines furnished pyrazolo[3′,4′:4,5] thiazolo[3,2-a]pyridines (14a,b) . The reaction of compound (1) with benzyli-denecyanoacetate (16) yielded 5-hydroxythiazolo[3,2-a]pyridine derivative (21) . Cyclization of bis(thiazolinone) (23) with benzylidenemalononitriles (10) produced bis(thiazolopyridine) derivatives (25a,b) .     

Chemical constituents of Eugenia catharinae and their antioxidant activity

Nine compounds were isolated from the leaves of Eugenia catharinae, namely monomethyl olivetol (1), β-sitosterol (2), stigmasterol (3), uvaol (4), erythrodiol (5), rotundic acid (6), quercetin (7), catechin (8) and myricitrin (9). The structures of 1–9 were established through analysis of their spectroscopic (¹H and ¹³C NMR) and spectrometric (MS) data. Compounds 1 and 6 are reported the first time in the Eugenia genus. In addition, these data were compared with those reported in the literature. The antioxidant activity of plant samples and compounds was measured using the DPPH radical scavenging assay. Flavonoids 7, 8, 9 and the ethanolic extract showed the best results, with IC₅₀ values of 20.94 μM, 44.20 μM, 30.01 μM and 58.82 μg/mL, respectively.     

New members of the [Mn6/oxime] family and analogues with converging [Mn3] planes

The synthesis, structural, and magnetic characterization of five new members of the hexanuclear oximate [Mn^III₆] family are reported. All five clusters can be described with the general formula [Mn^III₆O₂(R-sao)₆(R′-CO₂)₂(sol)_x(H₂O)_y] (where R-saoH₂ = salicylaldoxime substituted at the oxime carbon with R = H, Me and Et; R′ = 1-naphthalene, 2-naphthalene, and 1-pyrene; sol = MeOH, EtOH, or MeCN; x = 0–4 and y = 0–4). More specifically, the reaction of Mn(ClO₄)₂·6H₂O with salicylaldoxime-like ligands and the appropriate carboxylic acid in alcoholic or MeCN solutions in the presence of base afforded complexes 1–5: [Mn₆O₂(Me-sao)₆(1-naphth-CO₂)₂(H₂O)(MeCN)]·4MeCN (1·4MeCN); [Mn₆O₂(Me-sao)₆(2-naphth-CO₂)₂(H₂O)(MeCN)]·3MeCN·0.1H₂O (2·3MeCN·0.1H₂O); [Mn₆O₂(Et-sao)₆(2-naphth-CO₂)₂(EtOH)₄(H₂O)₂] (3); [Mn₆O₂(Et-sao)₆(2-naphth-CO₂)₂(MeOH)₆] (4) and [Mn₆O₂(sao)₆(1-pyrene-CO₂)₂(H₂O)₂(EtOH)₂]·6EtOH (5·6EtOH). Clusters 3, 4, and 5 display the usual [Mn₆/oximate] structural motif consisting of two [Mn₃O] subunits bridged by two O_oximate atoms from two R-sao^2? ligands to form the hexanuclear complex in which the two triangular [Mn₃] units are parallel to each other. On the contrary, clusters 1 and 2 display a highly distorted stacking arrangement of the two [Mn₃] subunits resulting in two converging planes, forming a novel motif in the [Mn₆] family. Investigation of the magnetic properties for all complexes reveal dominant antiferromagnetic interactions for 1, 2, and 5, while 3 and 4 display dominant ferromagnetic interactions with a ground state of S = 12 for both clusters. Finally, 3 and 4 display single-molecule magnet behavior with U_eff = 63 and 36 K, respectively.     

Theoretical study on the mechanism of OH + HCNO reaction

A detailed mechanistic study of the OH + HCNO reaction, in which the products P _i with i=1, 2, . . . ,7 are involved, is carried out by means of CCSD(T)/6-311G(d,p)//B3LYP/6-311G(d,p)+ZPVE computatio-nal method to determine a set of reasonable pathways. It is shown that P ₆ (CO + H₂NO) and P ₃ (HNO +HCO) are the major product channels with a minor contribution from P ₅ (NO + H₂CO), whereas the other channels for P ₁ (H₂O + NCO), P ₂ (NH₂ + CO₂), P ₄ (HCN + HO₂) and P ₇(CO + H₂ + NO) are less favorable. All these theoretical results are in harmony with experimental facts.     

A new alkaloid from Portulaca oleracea L. and its antiacetylcholinesterase activity

A new alkaloid, (10E, 12E)-9-ureidooctadeca-10, 12-dienoic acid, named oleraurea (1) and 10 known compounds, p-hydroxybenzaldehyde (2), p-hydroxybenzoic acid (3), p-hydroxyacetophenone (4), benzamide (5), (E)-p-coumaramide (6), (E)-ferulamide (7), soyalkaloid A (8), β-carboline-3-carboxylic acid (9), 2, 3, 4, 9-tetrahydro-1H-pyrido [3, 4-b] indole-3-carboxylic acid (10), (1S, 3S)-1-methyl-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid (11) were obtained from Portulaca oleracea L., in which, compounds 4, 5, 8–11 were isolated from the plant for the first time. The structure of the compound 1 was identified using spectroscopic methods including 1D and 2D NMR, HR-ESI-TOF-MS. The compounds 1, 5–11 presented anticholinesterase activities, but the P. oleracea extract (POE) presented very low anticholinesterase activity.     

A New Synthetic Approach Towards the Synthesis of 2-(3-Aryl-2H-1,4-benzthiazin-2-yl)-3-aryl-2H-1,4-benzothiazines

Synthesis of 2-(3-Aryl-2H-1,4-benzthiazin-2-yl)-3-aryl-2H-1,4-benzothiazines (3 a-e) from 3-aryl-5(4H)-isoxazolones (1 a-e) and 2-aminothiophenol (2).     

Syntheses and structures of three new coordination polymers with the flexible 1,4- bis (imidazol-1-yl)butane ligand

Three new coordination polymers [Co(bimb)₂(NCS)₂] _n (1), {[Co(bimb)₂(dca)₂]?·?CH₃CN} _n (2) and [Cu(bimb)₂(NO₃)₂] _n (3) (bimb?=?1,4-bis(imidazol-1-yl)butane, dca?=?dicyanamide) were synthesized and characterized. In 1, each Co(II) links two Co(II)'s by double bimb ligands and extends to form a one-dimensional chain containing the Co₂(bimb)₂ 22-membered metallocycle. 2 and 3 are two-dimensional (4, 4) networks linked by bimb bridges. The conformations of the bimb ligands in 1, 2 and 3 are analyzed.     

1-Norbornyllithium as a Precursor for the Synthesis of Novel Organic 1-Bicyclo[2.2.1]Heptane Derivatives and for the Improved Preparation of 1-Chloro-Bicyclo[2.2.2]octane

An improved strategy for synthesis of 1-chloro-bicyclo[2.2.2]octane is described in which the key compounds 1-norborny substituted ethyl formate(3) or 1-norbornylcarbaldehyde (7) were prepared from 1-norbornyllithium(1). The latter appeared as a useful precursor for the synthesis of various organic bridgehead substituted derivatives.     

3-(2-吡啶基)-1,2,4-三唑配体Co(II)Cu(II)和Cd(II)配合物的合成、结构及荧光性质

利用3-（2-吡啶基）-1,2,4-三唑配体（HL）和不同的金属盐设计合成了5个配合物[Co（HL）₂（H₂O）₂]（NO₃）₂（1）、[Cu₂（L）₂（NO₃）₂（H₂O）₄] （2）、[Cu₂（L）₂（AcO）₂（H₂O）₂]·6H₂O （3）、[Cu₂（L）₂（HL）₂（ClO₄）₂]·2CH₃CN （4）和[Cd₂（L）₂（HL）₂（NO₃）₂]·2H₂O （5）,并通过X射线单晶衍射、红外、元素分析、X射线粉末衍射和热重对配合物结构进行了表征。测试结果表明配合物1具有单核结构,并且可以通过氢键的相互作用形成二维超分子结构。配合物2~5为双核结构。配合物2和5可以通过氢键的相互作用形成二维超分子结构。配合物3通过氢键的相互作用形成三维超分子结构。研究了配合物中HL配体的配位模式。此外,研究了配体HL和配合物1和5的固态荧光性质及荧光寿命。     

β-secretase 1 inhibitory activity and AMP-activated protein kinase activation of Callyspongia samarensis extracts

Abstract

The methanolic extract of Callyspongia samarensis (MCS) significantly inhibited β-secretase 1 (IC₅₀ 99.82?µg/mL) in a dose-dependent manner and demonstrated a noncompetitive type of inhibition. Furthermore, it exhibited the highest AMPK activation (EC₅₀ 14.47?μg/mL) as compared with the standard, Aspirin (EC₅₀ >100?μg/mL). HPLC/ESI-MS analysis of MCS extract revealed 15 peaks, in which nine peaks demonstrated similar fragmentation pattern with the known compounds in literature and in database library: 5-aminopentanoic acid (1), 4-aminobutanoic acid (3), Luotonin A (4), (E)-3-(1H-imidazol-5-yl) prop-2-enoic acid (8), Galactosphingosine (10), D-sphingosine (11), 5,7,4′-trihydroxy-3′,5′-dimethoxyflavone (12), hydroxydihydrovolide (13), and 3,5-dibromo-4-methoxyphenylpyruvic acid (14); and 6 peaks are not identified (2, 5–7, 9, and 15). Acute oral toxicity test of MCS extract revealed that it is nontoxic, with an LD₅₀ of >2000?mg/kg. Assessment of BBB permeability of MCS extract showed that compound 15 was able to cross the BBB making it a suitable candidate for developing CNS drugs.