Volume 62, Issue 4

A hydrogen-bonded chloride-hydrate assembly {[(H 2 O) 4 Cl 2 ] 2− }∞ has been ion-countered by the complex cations [Fe([9]aneS 3 ) 2 ] 2+ ([9]aneS 3 = 1,4,7-trithiacyclononane). In {[(H 2 O) 4 Cl 2 ] 2− }∞, four water molecules and two chloride ions are self-assembled to form a one-dimensional supramolecular array of O-H···O and O-H···Cl hydrogen bonding, which consists of fused fourand six-membered rings. The discrete cation [Fe([9]aneS 3 ) 2 ] 2+ has a nearly regular octahedral FeS 6 core with an average Fe-S bond length of 2.2586(5) Å .

The new complex Cu[L 1 ]Cr 2 O 7 has been synthesised with the N,N′-bis(2-pyridylmethylene) butane-1,4-diamine Schiff base L1, [NC 5 H 4 CH=N(CH 2 ) 4 N=CHC 5 H 4 N], and characterised with elemental analyses and different spectroscopic and electrochemical studies. The structure of the new complex has been established by single crystal X-ray diffraction. The complex crystallises in the monoclinic system with space group P2 1 /c having cell parameters a = 14.7(5), b = 9.22(2), c = 16.2(5) Å , β = 116.9(1)°, and Z = 4. The Cr 2 O 7 2− unit is bonded through one terminal oxygen donor end to the central Cu(II) chelated by the Schiff base ligand.

Reaction of CuBr with an excess of 2,3-dimethylpyrazine in acetonitrile leads to the formation of the literature known ligand-rich 1 : 1 compound poly[μ 2 -bromo-μ2-2,3-dimethylpyrazine- N,N′-copper(I)] (1). On heating this compound in a thermobalance a transformation into the new ligand-deficient 2 : 1 compound poly[di-μ3-bromo-μ2-2,3-dimethylpyrazine-N,N′-dicopper(I)] (3) is observed, which later was also prepared in solution. This compound crystallizes in the monoclinic space group P2 1 /n with all atoms in general positions. In the crystal structure the Cu atoms are surrounded by three Br atoms and one 2,3-dimethylpyrazine ligand within a distorted tetrahedron. The tetrahedra are connected via common Br edges into CuBr double chains, which are connected by the ligands into layers located in the ab plane. The formation of compounds 1 and 3 was also investigated in solution. The results have shown that compound 1 can only be prepared if an excess of the ligand is used. If CuBr and the ligand are reacted in a ratio of 1 : 1, in the beginning the literature known ligand-deficient 3 : 2 intermediate catena[tribromo-μ 2 -bis(μ 2 -2,3-dimethylpyrazine- N,N′)-tricopper(I)] (2) is obtained, which transforms within minutes into compound 3. If a crystalline suspension of compound 1 is stirred in acetonitrile a transformation into the most stable compound 3 is also observed. The luminescence properties of compounds 1 and 3 were investigated. The complexes show differences mainly in the emission spectra.

A short route for the preparation of tetradentate amine-thioether and amine-thiolate ligands derived from thiosalen is reported. The ligating properties of several of the synthesized ligands towards Ni(II) has been examined. The diamine-dithiophenolate ligands (L 6 ) 2− [H 2 L 6 = N,N′-dimethyl-N,N;-di(2- mercaptobenzyl)-ethane-1,2-diamine] and (L 7 ) 2− [H 2 L 7 = N,N′-di(2-mercaptobenzyl)-piperazine] support the formation of four-coordinate Ni II N 2 S 2 complexes [Ni II (L 6 )] (10) and [Ni II (L 7 )] (11). By contrast, the amine-thioethers 2 [N′,N″-bis(2-(tert-butylthio)benzyl)ethane-1,2-diamine], L 2 [8,11- diaza-5,13-dibenzo-1,4-dithia-cyclotetradecane] and its N-methylated derivative L 2,Me were found to produce the six-coordinate Ni(II) complexes [Ni II Cl 2 (2) 2 ] (9), [Ni II 2 (μ-Cl) 2 (L 2 ) 2 ][ClO 4 ] 2 (12), [Ni II (NCS) 2 (L 2 )] (13), and [Ni II Cl 2 (L 2,Me )] (14). The results of IR, NMR and UV/vis spectroscopy and the crystal structures of complexes 9 - 13 are reported.

The reaction of four equivalents of phenyl or tert-butyl isocyanate with the pyridine-derived tetraamine 2,6-C 3 H 3 N[CMe(CH 2 NH 2 ) 2 ] 2 in toluene gives high yields of the quadruply ureido substituted products 2,6-C 5 H 3 N[CMe(CH 2 R) 2 ] 2 [R = -NH(CO)NHPh and -NH(CO)NH t Bu]. Full spectroscopic data for both compounds are given. A single crystal X-ray structure determination of the phenyl derivative reveals an intricate network of both intra- and intermolecular hydrogen bonds involving the C=O and both NH functionalities in all ureido groups.

A series of 4-nitroimidazole derivatives bearing substituted piperazines (5, 8, 9, 12, 14, 16, 17, and 19 - 21) were synthesized with the aim to develop new non-nucleoside reverse transcriptase inhibitors (NNRTIs). The newly synthesized compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. All compounds are inactive, except compound 21 which showed inhibition of HIV-1 with EC 50 0.20 μg/mL, and therapeutic indexes (SI) of 12.

The coupling reaction of 3-(dimethylamino)acrolein (2a) and ethyl 3-(dimethylamino)acrylate (2b) with arenediazonium chlorides afforded the 2-(arylhydrazono)aldehydes 1a - e. Compounds 1a, b reacted with hydroxylamine hydrochloride to yield the oximes 4a, b. The dioxime 5 was obtained from reaction of 1a with an excess of hydroxylamine hydrochloride. This dioxime afforded the 1,2,3-triazole carbonitrile 6 when treated with acetic anhydride, while α-hydrazono propionitrile 8 was obtained when 5 was treated with acetic acid. Compounds 1a - e could be utilized for the synthesis of a variety of pyrazoles and arylazolopyrimidines via reaction with hydrazines, haloketones and aminoazoles, respectively.

A new, “green” and efficient one-pot protocol for the synthesis of bis(indoyl)methanes from primary alcohols using Bi(NO 3 ) 3 ·5H 2 O is described. This procedure performs chemoselectively through a solvent-free reaction and the products are obtained in high to excellent yields.

The reaction of styryl ketonic Mannich bases 2a - c with phenylhydrazine leads to 3-functionalized 2-pyrazolines 4 or 6 depending on the reaction conditions. 3-[β -(Arylamino)ethyl]-2-pyrazolines 8a,b were obtained via transamination between the methiodide salt 7 and primary arylamines. Treatment of 1-(p-anisyl)-1,2,5-tri(N-piperidino)pentan-3-one (11) with phenylhydrazine affords the 3,4-difunctionalized 2-pyrazoline 12. The reactions of the keto bases 19 or 21 with hydrazines lead to 4-functionalized 2-pyrazolines 20 and 22, the N-Mannich bases 23 and 24 are obtained from 22a. The synthesis of 3-[β -(phenylthio)ethyl]-2-pyrazolines 28a,b has been achieved by treating 26 or 27 with phenylhydrazine.

Fourteen dimethyl 4-aryl-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylates (DHPs) were evaluated by means of single crystal X-ray diffraction in order to investigate the effects of the structure in the crystals on the solid state 13 C NMR chemical shifts. These include the analysis of three DHPs containing two molecules per asymmetric unit. The chiral rotamer unit generated by the s-cis/s-trans orientation of the carbonyl groups, as well as by rotation of the 4-phenyl ring out of the bisecting plane containing the N1, C4, C7 atoms, resulted in a significant magnetic non-equivalence for the C2-CH 3 /C6-CH 3 and the COOCH 3 pairs of signals. The solid state 13 C NMR data reveal that the substitution pattern of the phenyl ring has a marked effect on the extent to which the signals of the carbonyl carbon atoms and those of C-2/C-6 peaks are split.

A simple synthesis of prostaglandin E 1 (PGE 1 ) is described. The key steps are an asymmetric Michael addition to establish the desired (R)-configurations at C8 and C12 of the 2- (trimethylsilyl)ethoxymethyl- (SEM) protected PGE1 and its one-pot deprotection with magnesium bromide in high yield. This method is potentially useful for the preparation of other modified prostaglandins.

A new polyketide, TMC-151 A monoacetate (1), along with a known analogue, TMC-151 F (2), was isolated from ethyl acetate extracts of the fermentation broth of Bionectria ochroleuca isolated in Taiwan. Their structures were elucidated on the basis of spectroscopic analysis. The antiproliferative activities of 1 and 2 were evaluated against MT-2 (human leukemia), A498 (human renal carcinoma), NPC-tw01 (human nasopharyngeal carcinoma), H-226 and A549 (non-small cell lung cancer) cell lines, and their IC 50 values ranged from 18.3 to 40.2 μM.

Laurentixanthone C (1), a new xanthone, was isolated from the stem bark of Vismia laurentii (Guttiferae or Clusiaceae), in addition to the known compounds vismiaquinone (2), bisvismiaquinone (3), and dammaradienol (4). The structures were established based on spectroscopic studies, notably of the 2D NMR spectra. Preliminary results showed that 1 is algicidal and strongly antibacterial against the Gram-positive bacteria Bacillus megaterium and Chlorella fusca, respectively.

Xylogranatin E, the second phragmalin with a rare oxygen bridge between C 1 and C 29 found in nature, was isolated from the fruit of a Chinese mangrove, Xylocarpus granatum. Its structure was determined by spectroscopic analysis. Complete assignment of 1 H and 13 C NMR data of xylogranatin E was achieved by 2D NMR techniques, including 1 H- 1 H COSY, HSQC, HMBC and NOESY spectra.

A new trechonolide-type withanolide, jaborosolactol, possessing a hemiketal ring system and a 5-membered lactol, has been isolated from the aerial parts of Jaborosa lanigera. The structure was elucidated based on spectroscopic and spectrometric methods (1D and 2D NMR, MS). The feeding deterrent activity of the compound against the Mediterranean fruit fly Ceratitis capitata was examined.

A novel norditerpene was isolated from the flower of Eupatorium adenophorum, named (4aR,7R,8S,8aR)-1,2,4a,5,6,7,8,8a-octahydro-8-[3-methylenebut-4-alyl]-4,4a,7,8-tetramethylnaphthalen- 2(1H)-one (1). Its structure was established by extensive NMR experiments. Based on the diversity of the side chains, a possible biodegradation pathway for the compound from the clerodane skeletone is proposed.

Phytochemical studies on the ethanolic extract of Barleria prionitis of Sri Lankan origin have resulted in the isolation of a new compound, balarenone (1), along with three known compounds, pipataline (2), lupeol (3) and 13,14-seco-stigmasta-5,14-diene-3-α-ol (4). The structures of 1 - 4 were elucidated with the aid of extensive NMR spectroscopic studies. Compounds 1 - 4 showed moderate inhibitory activity against glutathione S-transferase (GST) and acetylcholinesterase (AChE). Compounds 1, 2 and 4 also exhibited antibacterial activity against Bacillus cereus and Pseudomonas aeruginosa (25 μg/disk). Three different derivatives of compound (2), 7,8-epoxypipataline (5), 8- amino-7-hydroxypipataline (6) and 7,8-dibromopipataline (7) were synthesized to evaluate them for GST and AChE inhibitory activities. Household microwave radiations were used to synthesize compound (6). Among all tested compounds, 8-amino-7-hydroxypipataline (6) exhibited a significant AChE inhibitory activity with an IC 50 value of 36.8 μM.

Two new sesterterpenes, 14β -methylleucosesterterpenone (1) and 17α-hydroxyleucosceptrine (2), along with a known triterpene, hypoglauterpenic acid (6), were isolated from the Leucosceptrum canum of Nepalese origin. The structures were elucidated on the basis of spectroscopy techniques.

Microbial transformation of 11α-hydroxyprogesterone (1) with Cunninghamella elegans, Gibberella fujikuroi, Fusarium lini, and Candida albicans yielded 11α,15α,16α-trihydroxypregn-4- ene-3,20-dione (3), 11α-hydroxy-5α-pregnane-3,20-dione (4), 6β ,11α-dihydroxypregn-4-ene-3,20- dione (5), 11α-hydroxypregna-1,4-diene-3,20-dione (6), 11α,17β -dihydroxyandrost-4-en-3-one (7), and 11α,15α-dihydroxypregn-4-ene-3,20-dione (8). On the other hand, microbial transformation of 17α-hydroxyprogesterone (2) with Cunninghamella elegans and Fusarium lini yielded 11α,17α- dihydroxypregn-4-ene-3,20-dione (9), and 17α-hydroxypregna-1,4-diene-3,20-dione (10). The structures of the metabolites 3 - 10 were deduced on the basis of spectroscopic methods. Compound 3 was identified as a new metabolite, which exhibited a promising inhibitory activity against the α-glucosidase enzyme.

MALDI-TOF-MS was used for the first time as a direct screening method to analyse sponge tissue (Stylissa caribica). In order to validate this method the results were compared with a HPLC-ESI-MS analysis of the crude extract from the investigated sponge. Both methods showed a good agreement in their results, allowing for the rapid identification of 15 pyrrole-imidazole alkaloids.

Two novel ester ferrocenophanes have been prepared by esterification of 1,1′-ferrocenedi(carbonyl chloride) with glycol and 1,4-butanediol, respectively. Both of them have been characterized by IR, elemental analysis, MALDI-TOF MS and 1 H NMR spectroscopic methods, and their structures have been elucidated by X-ray diffraction. The intermolecular associations based on C-H···O hydrogen bonds have also been discussed. These molecules are assembled into chains, and the chains are further assembled into a 3D structure through several hydrogen bonds.

The intermetallic cadmium compounds LaPdCd 2 and PrNi 0.951(4) Cd 2 were synthesized from the elements in sealed tantalum tubes in an induction furnace. Both phases were investigated by X-ray diffraction on powders and single crystals: MgCuAl 2 -type, Cmcm, Z = 4, a = 431.9(1), b = 1015.7(4), c = 835.7(2) pm, wR2 = 0.0436, 326 F 2 values, 16 variables for LaPdCd 2 and a = 420.26(8), b = 981.0(2), c = 815.3(1) pm, wR2 = 0.0404, 604 F 2 values, 17 variables for PrNi 0.951(4) Cd 2 . A small nickel deficit was observed for the PrNi 0.951(4) Cd 2 crystal. The cadmium atoms build up orthorhombically distorted three-dimensional networks (Cd-Cd distances: 302 - 334 pm) that resemble the structure of hexagonal diamond, lonsdaleite. Together with the palladium (nickel) atoms, [PdCd2] and [Ni 0.951(4) Cd 2 ] networks are formed which leave distorted hexagonal channels for the rare earth atoms.

The intermetallic cerium compounds CePdGe, CePtSi, and CePtGe were synthesized from the elements by arc-melting and subsequent annealing. The structure of CePtSi was refined from single crystal X-ray diffraction data: LaPtSi-type (ordered α-ThSi 2 version), 14 1 md, a = 419.6(1) and c = 1450.0(5) pm, wR2 = 0.0490, 362 F 2 values and 16 variables. The Pt-Si distances within the three-dimensional [PtSi] network are 242 pm, indicating strong Pt-Si interactions. Hydrogenation of the three compounds at 623 K and 4 MPa H 2 gave no indication for hydride formation.

The ligand-rich precursor compound tetra-μ-chloro-bis (μ2-2,3-dimethylpyrazine)-tetrakis-(acetonitrile-N)tetracopper(I) (1) was prepared by the reaction of CuCl with 2,3-dimethylpyrazine in acetonitrile. On heating this compound decomposes quantitatively in a single step directly to the ligand-deficient coordination polymer di-μ3-chloro-(μ2-2,3-dimethylpyrazine-N,N′)copper(I).