Synthesis of PDE IVb inhibitors. 1. Asymmetric synthesis and stereochemical assignment of (+)- and (-)-7-[3-(cyclopentyloxy)-4-methoxyphenyl]hexahydro-3H-pyrrolizin-3-one

Asymmetric synthesis of GlaxoSmithKline's highly potent phosphodiesterase inhibitor 1 has been accomplished in nine steps and 16% overall yield. The original strategy suggested involves as a key step the silylation of enantiopure six-membered cyclic nitronates 4 obtained by a highly stereoselective [4 + 2]-cycloaddition of an appropriate nitroalkene 5 to trans-1-phenyl-2-(vinyloxy)cyclohexane. Functionalization of the resulting 5,6-dihydro-4H-1,2-oxazine and subsequent stereoselective reduction of 1,2-oxazine ring in intermediate 2 furnished the pyrrolizidinone framework with the recovery of chiral auxiliary alcohol.     

Element Fractionation Analysis for Milk in Its Real Matrix by Inductively Coupled Plasma Optical Emission Spectrometry

Fractionation of elements in food is essential for understanding and prediction of its bioavailability, effects, and toxicity. In the present study, an analytical fractionation scheme for milk samples was developed for the common elements, such as Fe, Cu, Zn, Mn, Mg, Ca, Cr, Ni, Mo, Al, Pb, Sn, V, Ba, Co, and Cd. For this purpose, applying a sequential separation procedure, the protein, lipid, and serum fractions were obtained separately. The recovery percentages were in the range of 96.3–104.0 for the separation of fractions in the synthetic milk. The results achieved in the paper were compared with reported literature data. Additionally, the fractionation pattern for each metal studied was different relating to the origin of milk. Although there were some exceptions, it was seen that Fe, Cu, and Al preferred to be in protein fraction; however, Zn, Mn, Mg, Ca, Cr, Ni, and Mo preferred to be in serum fraction.     

The synthesis of oligoether-substituted benzimidazolium bromides and their use as ligand precursors for the Pd-catalyzed Heck coupling in water

The oligoether-substituted (CH₃(OCH₂CH₂)_n-; n = 1, 2 or 3) benzimidazolium bromides (3-7) and oligoether-linked (-CH₂(CH₂OCH₂)_nCH₂-, n = 1, 2 or 3) bisbenzimidazolium dibromides (8-13) were prepared by quarternization of N-substituted benzimidazoles (1 and 2) with the bulky benzyl bromides (ArCH₂Br: Ar = C₆H₂(CH₃)₃-2,4,6 and C₆(CH₃)₅). trans-Bis(carbene) palladium(II) complexes 14 and 15 derived from 4 and 6 were synthesized by using Ag complexes as carbene-transfer agents in dichloromethane at ambient temperature. In addition, the reactions of 4 and 6 with Pd(OAc)₂ and NaBr gave the Pd(II) dimers 16 and 17 which can readily be cleaved by triphenylphosphine to afford the benzannulated monocarbene (NHC) monophosphine Pd(II) complexes [PdBr₂(NHC)(PPh₃)] (18 and 19). All compounds have been fully characterized by using elemental analysis, ¹H, ¹³C and ³¹P NMR spectroscopies. X-ray diffraction studies on single crystals of 19a and 19b confirm the cis square planar geometry. In situ formed complexes from Pd(OAc)₂ and benzimidazolium salts (3-13) and preformed Pd(II) complexes 14, 15, 18 and 19 were tested as catalyst for the Heck coupling reaction in water. The influence of the oligoether and benzyl substituents on N atoms and CH₃-substituents on the 5,6-positions of benzimidazole frame were investigated under the same conditions in the Heck coupling reaction. In situ formed catalysts showed better conversions than the isolated Pd(II) complexes. The length of the oligoether spacer significantly increases the activity. The salts with two benzimidazole moieties connected by an oligoether as the spacer 8-13 showed similar catalytic activities in the Heck coupling reaction with the mono salts 3-7 bearing corresponding oligoethers on the N atom.     

Real-time PCR analysis of the apoptosis related genes in ATRA treated APL t(15;17) patients

All-trans retinoic acid (ATRA) treatment of the acute promyelocytic leukemia (APL) have subsequently resulted in cell apoptosis, but the molecular mechanism of this effect remains elusive. In order to understand a possible involvement of genes regulating apoptotic signal pathways, expression levels of bcl2, bax, dapk1, myc, bad, wt1, and mcl genes were analyzed during ATRA treatment in five APL patients with t (15;17) using Real- time PCR (LightCycler). Two samples from each patient were compared to each other: primary diagnostic sample and a sample taken at remission. Effect of the ATRA treatment was demonstrated by the concomitant induction of cd14 and il1beta genes in four patients. Also other apoptosis related genes were found down-regulated in general but especially the down regulated levels of wt1 and bax attract attention. Result suggested that ATRA dependent apoptosis of APL was under the control of both internal and external pathways without relationships to the amount of the blast populations. Ratio of bcl2 to bax may be more important for this regulation than the ratio of bcl2 to bad. Either bcl2 family or less known apoptosis related genes as wt1 will still be required to further studies in this setting.     

New C-C coupling reaction of cyclic nitronates with carbon nucleophiles. Umpolung of the conventional reactivity of nitronates

Cyclic six-membered nitronates 1 are involved in diastereoselective C-C coupling reactions with various nucleophiles in the presence of either catalytic or stoichiometric amounts of TBDMSOTf to give the previously unknown N-siloxytetrahydrooxazines. The intermediacy of N,N-bis(oxy)iminium cations was proven by NMR data.     

Real-Time PCR analysis of af4 and dek genes expression in acute promyelocytic leukemia t (15;17) patients

Among several newly identified oncogenes, dek and af4 are attractive targets for researchers interested with leukemia. In this study quantitative Real-Time RT-PCR technique was used to define alterations in expression of dek and af4 genes associated with acute promyelocytic leukaemia (APL) t (15; 17). RNA samples obtained from bone marrow aspirates of fourteen APL patients, cDNA portions were labelled with Syber Green 1 dye and LightCycler analysis have been performed. Expression changes in patients were found not significant in comparison to healthy donors for af4 (P = 0.192) and dek (P = 0.0895). We suggest that af4 gene may have a role in leukomogenesis restricted to lymphoblastic lineage; also further studies must carry on with a larger series of patients in order to understand the relationship between the dek gene and APL. Our study was the first attempt for analysing dek and af4 genes in APL t (15; 17) patients by quantitative Real-Time RT-PCR. This rapid and sensitive method could be used to screen these genes in different types of leukaemia.     

Synthesis,IR Spectra,Thermal Analysis and Crystal Structures of Bis(saccharinato)mercury(II) Complexes with 2–Aminomethylpyridine and 2–Aminoethylpyridine

Two bis(saccharinato) (sac) complexes of mercury(II) with 2–aminomethylpyridine (ampy) and 2–aminoethylpyridine (aepy) were synthesized and characterized by means of elemental analysis, FT–IR spectroscopy and thermal analysis and single crystal X–ray diffraction. trans–[Hg(sac)₂(ampy)₂] ( 1 ) crystallizes in the monoclinic space group P2₁/c [a = 10.8274(4), b = 16.4903(6), c = 7.7889(3) Å; β = 99.500(1)°] and [Hg(sac)₂(aepy)] ( 2 ) also crystallizes monoclinic in space group P2₁/n [a = 9.0423(4), b = 14.0594(6), c = 18.0146(8) Å; ß = 98.806(1)°]. Both 1 and 2 consist of neutral monomeric units. The mercury(II) ion in 1 lies on an inversion centre and exhibit distorted octahedral coordination by two sac anions and two ampy ligands, whereas the mercury(II) ion in 2 is tetrahedrally coordinated by an aepy and two sac ligands. The sac ligands in both complexes are N–coordinated, while the ampy and aepy ligands act as a bidentate ligand forming two symmetrically chelate rings around the mercury(II) ion.     

Photochemical reactions of chromium hexacarbonyl with tetraalkyldiphosphine disulfides

New complexes [Cr(CO)₄(R₂P(S)P(S)R₂)] and [Cr₂(CO)₁₀(-R₂P(S)P(S)R₂)] (R = Me, Et, Pr ⁿ , Bu ⁿ ), (1a)–(1d) and (2a)–(2d) [(1a), R = Me; (1b), R = Et; (1c), R = Pr ⁿ ; (1d), R = Bu ⁿ ; (2a), R = Me; (2b), R = Et; (2c), R = Pr ⁿ ; (2d), R = Bu ⁿ ] have been prepared by the photochemical reaction of Cr(CO)₆ with R₂P(S)P(S)R₂ (R = Me, Et, Pr ⁿ and Bu ⁿ ) and characterized by elemental analyses, FT-i.r., ³¹P-[¹H]-n.m.r. spectroscopy and FAB-mass spectrometry. The spectroscopic data suggest cis-chelate bidentate coordination of the ligand in [Cr(CO)₄(R₂P(S)P(S)R₂)] and cis-bridging bidentate coordination of the ligand between two metals in [Cr₂(CO)₁₀(-R₂P(S)P(S)R₂)] (R = Me, Et, Pr ⁿ and Bu ⁿ ).     

Bis­(saccharinato‐κN)zinc(II) com­plexes with N,N′‐bidentate 2‐amino­methyl­pyridine and 2‐amino­ethylpyridine

The structures of trans‐bis[2‐(amino­methyl)­pyridine‐κ²N,N′]­bis­(saccharinato‐κN)­zinc(II), [Zn(C₇H₄NO₃S)₂(C₆H₈N₂)₂], (I), and [2‐(amino­ethyl)­pyridine‐κ²N,N′]bis­(saccharinato‐κN)­zinc(II), [Zn(C₇H₄NO₃S)₂(C₇H₁₀N₂)], (II), exhibit octa‐ and tetrahedrally coordinated Zn^II atoms, respectively. The di­amine ligands behave as N,N′‐bidentate ligands, while saccharinate (sac) is coordinated through the N atom. In (I), the complex lies about an inversion centre with the Zn atom disordered and displaced by 0.256 (2) Å from a centre of symmetry towards a sac N atom. The crystal structure of (I) is stabilized by N—H⋯O hydrogen bonds and the crystal packing of (II) is determined by hydrogen bonding as well as weak π–π stacking interactions between the sac ligands.     

Novel and Validated Spectrophotometric Matrix Matching Method for Simple and Rapid Determination of Chromium in Oily Media

N,N’-bis(4-methoxysalicylidene) ethylenediamine is proposed as analytical reagent for the direct determination of chromium in original matrix of liquid oils. The method is based on the complexation of N,N’-bis(4-methoxysalicylidene) ethylenediamine and chromium in n-hexane∶acetone (1∶4) medium and spectrophotometric determination at 355 nm against reagent blank. Complexation of MSE and chromium is completed in 20 seconds at molar ratio 1∶1. The molar absorptivity and the formation constant of the complex are determined as 9 740 L·mol-1·cm-1 and 3.6(±0.1)×105, respectively. Beer’s law is obeyed in range 0.02～1.50 mg·L-1 chromium concentration. Limits of detection and quantification of the suggested method were 7.5 and 25.1 μg·kg-1, respectively. The accuracy and precision of the method was checked by finding mean recovery and relative standard deviation by oil-based chromium standard analysis as 96.4%±1.4% and 1.5%, respectively. The practical applicability of elaborate method was tested using oil-based chromium standard spiked and unspiked corn, sunflower, soybean, olive and canola oils.