L-(-)-Menthol in the Synthesis of Key Synthons for Optically Active Methyl-Branched Insect Pheromones

A synthesis of optically active 4S-methylhexanal, 1-bromo-3S-methylheptane, and 1-bromo-3S-methylundecane, which are key synthons for several methyl-branched insect pheromones, that is based on chemically selective transformations of 6-tosyloxy- and 6-iodoisopropyl-4R-methylhexanoates that are available from L-(-)-menthol was proposed. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 592–593, November–December, 2005.     

Insect pheromones and their analogs. VIII. Synthesis of the (Z) and (E) isomers of 2-methyloctadec-7-ene and of 2-methyl-7,8-epoxyoctadecane

A highly stereospecific method for the synthesis of racemic (Z)-disparlure has been developed which is based on the reduction of 2-methyloctadec-7-yne with the aid of 9-borabicyclo[3.3.1]nonane and the epoxidation of the resulting (Z)-2-methyloctadec-7-ene with p-methoxycarbonylperbenzoic acid. The¹³C NMR spectra of the (Z) and (E) isomers of 2-methyloctadec-7-ene and 2-methyl-7,8-epoxyoctadecane, which unambiguously confirm the structures of these compounds, are given. It has been established that (E)-2-methyloctadec-7-ene exhibits a moderate attractant activity while the (Z) isomer does not attract the gypsy moth. The addition of 5–25% of (E)-disparlure increases the biological activity of (Z)-disparlure.Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 630–634, September–October, 1983.     

Numerical study of the thermal processes occurring in materials under irradiation with high-energy heavy ions

Numerical simulation of the thermal processes occurring in indium phosphide under the action of a heavy gold ion with the energy E ₀ = 200 MeV is carried out. The problem is solved taking into account phase transitions of the melting and evaporation types. Numerical studies are carried out on the basis of a modified thermal-peak model and the obtained results are analyzed.     

Chlorido[N,N′‐dibenzyl‐N′′‐(trichloroacetyl)phosphoramidato‐κ2O,O′](1,10‐phenanthroline‐κ2N,N′)copper(II)

In the title complex, [Cu(C₁₆H₁₆Cl₃N₃O₂P)Cl(C₁₂H₈N₂)], the Cu^II cation presents a square‐pyramidal environment, where the CuO₂N₂ base is formed by two O atoms from carbonyl and phosphoryl groups, and by two N atoms from a 1,10‐phenanthroline molecule. A coordinated Cl atom occupies the apex. N—H...Cl hydrogen bonds link the molecules into one‐dimensional chains. The trichloromethyl group is rotationally disordered over two positions, with occupancies of 0.747 (7) and 0.253 (7).     

Alkylation of 3‐Phenyl‐1H‐pyrazolo[4,3‐c] quinoline: Theoretical Analysis of Regioselectivity

The interaction of 3‐phenyl‐1H‐pyrazolo[4.3‐c]quinoline with alkylating agents in the presence of NaH leads mainly to N1‐substituted derivatives. The regioselectivity of the reaction has been studied using AM1 semi‐empirical calculations in the isolated molecule approximation.     

New Luminescent Lanthanide Tetrakis-Complexes NEt4[LnL4] Based on Dimethyl-N-Benzoylamidophosphate

New lanthanide dimethyl-N-benzoylamidophosphate (HL) based tetrakis-complexes NEt₄[LnL₄] (Ln³⁺=La, Nd, Sm, Eu, Gd, Tb, Dy) are reported. The complexes are characterized by means of NMR, IR, absorption, and luminescent spectroscopy as well as by elemental, X-Ray, and thermal gravimetric analyses. The phenyl groups of the four ligands of the complex anion are directed towards one side, while the methoxy groups are directed in the opposite side, which makes the complexes under consideration structurally similar to calixarenes. The effect of changing the alkali metal counterion to the organic cation NEt₄⁺ on the structure and properties of the tetrakis-complex [LnL4]^- is analyzed. The complexes exhibit bright characteristic for respective lanthanides luminescence. Rather high intensity of the band of ⁵D₀→⁷F₄ transition, observed in the luminescence spectrum of NEt₄[EuL₄], is discussed based on theoretical calculations.     

Antisense oligonuclotides with oxetane-constrained cytidine enhance heteroduplex stability,and elicit satisfactory RNase H response as well as showing improved resistance to both exo and endonucleases

Antisense oligonucleotides (AONs) with single and double oxetane C modifications [1',2'-oxetane constrained cytidine, 1-(1',3'-O-anhydro-beta-D-psicofuranosyl)cytosine] have been evaluated, in comparison with the corresponding T-modified AONs, for their antisense potentials by targeting to a 15mer complementary RNA. Although the C modified mixmer AONs show approximately 3 degrees C drop per modification in melting temperature (Tm) of their hybrid AON-RNA duplexes, they are found to be good substrates for RNase H, in comparison with the native AON-RNA duplex. An AON with double C modifications along with 3'-DPPZ (dipyridophenazine) conjugation shows the Tm of the hybrid duplexes as high as that of the native, and the RNase H activity as good as its unconjugated counterpart. A detailed Michaelis-Menten kinetic analysis of RNase H cleavage showed that the single and double C modified AON-RNA duplexes as well as double C modifications along with 3'-DPPZ have catalytic activities (kcat) close to the native. However, the R Nase H binding affinity (1/Km) showed a slight decrease with increase in the number of modifications, which results in less effective enzyme activity (kcat/Km) for C modified AON-RNA duplexes. All oxetane modified AON-RNA hybrids showed a correlation of Tm with the 1/Km, Vmax, or Vmax/Km. The C modified AONs (with 3'-DPPZ), as in the T counterpart, showed an enhanced tolerance towards the endonuclease and exonuclease degradation compared to the native (the oxetane-sugar and the DPPZ based AONs are non-toxic to K562 cell growth, ref. 18). Thus a balance has been found between exo and endonuclease stability vis-a-vis thermostability of the heteroduplex and the R Nase H recruitment capability and cleavage with the oxetane-constrained cytidine incorporated AONs as potential antisense candidates with a fully phosphate backbone for further biological assessment.     

Synthesis and investigations of mixed-ligand lanthanide complexes with N,N′-dipyrrolidine-N′′-trichloracetylphosphortriamide,dimethyl-N-trichloracetylamidophosphate, 1,10-phenanthroline and 2,2′-bipyrimidine

Coordination compounds with general formula [Ln(L¹)₃phen], where Ln = Nd, Eu, Er, Yb, HL¹ = N,N′-dipyrrolidine-N′′-trichloracetylphosphortriamide, phen = 1,10-phenanthroline; [Ln(L¹)₃bpm], where Ln = La, Nd, Eu, Gd, Er, Y, bpm = 2,2′-bipyrimidine and [{Ln(L²)₃}₂(μ-bpm)], where Ln = La, Nd, Eu, Gd, Er, Y, HL² = dimethyl-N-trichloracetylamidophosphate have been synthesized and characterized by means of IR and UV–Vis spectroscopy. Crystal structures of [Nd(L¹)₃phen] (1), [Nd(L¹)₃bpm] (2) and [{Nd(L²)₃}₂(μ-bpm)] (3) have been determined. It was found, that in the deprotonated form the phosphoryl ligands (L¹)^? and (L²)^? are coordinated to the neodymium atoms in a bidentate manner via the oxygen atoms of the phosphoryl and the carbonyl groups with formation of six-membered metallocycles. In the case of compounds 1 and 2 the 1,10-phenanthroline (or 2,2′-bipyrimidine) molecules are coordinated to the metals in a bidentate manner via the nitrogen atoms. In contrast 2,2′-bipyrimidine acts in the bidentate-bridge mode forming binuclear complex 3. Variable-temperature magnetic susceptibility measurements of 3 and [{Gd(L²)₃}₂(μ-bpm)] (4) reveal a weak antiferromagnetic interaction between the two magnetic centres, whereas in the case of [{Eu(L²)₃}₂(μ-bpm)] (5) the presence of spin–orbit coupling leads to a deviation from the Curie and Curie–Weiss laws.     

A modified thermal peak model with the source function dependent on ion velocity for materials bombarded by heavy ions

A modified thermal spike model is proposed. In contrast to the previous model, this scheme involves a source function dependent on ion energy losses determined by the penetration depth of a target and the characteristic time of ion penetration until comes to a complete stop. Such an approach is especially significant for confirming its applicability for track formation processes observed in materials because, as is shown, characteristic times appreciably exceed the periods of phonon oscillations with frequencies of 10¹³ Hz or more. The performed calculations make it possible to infer that the source function of the modified model describes thermal processes differently than does the commonly used source function. It is established that the temperature of a material exceeds the solid-liquid transition temperature in the cylindrical regions with sizes that are smaller than those calculated without allowance for ion motion.