Polyvariant modification of di- and tetrahydroxydinaphthylmethanes

Modification of di- and tetrahydroxydinaphthylmethanes yielded a new family of aromatic systems differing by the nature, the number, and positions of functional groups and by the mode of fusion of the naphthalene nuclei. The effect of the starting dinaphthylmethane structure on the modification route was demonstrated.     

1,9-Dialkoxyanthracene as a (1)O2-sensitive linker

We developed a (1)O(2)-sensitive linker based on a 9,10-dialkoxyanthracene structure. Its cleavage in the presence of (1)O(2) is quick and high-yielding. A phosphoramidite containing this fragment was prepared and coupled to a variety of molecular fragments, including nucleosides, fluorescent dyes, and a cholesteryl derivative. On the basis of this building block we prepared a fluorogenic probe for monitoring (1)O(2) in live mammalian cells and visible-light-activated "caged" oligodeoxyribonucleotides. In particular, the fluorogenic (1)O(2) probe is a conjugate of 4,7,4',7'-tetrachlorofluorescein and N,N,N',N'-tetramethylrhodamine coupled to each other via the (1)O(2)-sensitive linker. Fluorescence of the dyes in this probe is quenched. In the presence of (1)O(2), the linker is cleaved with formation of 9,10-anthraquinone and two strongly fluorescent dyes: 4,7,4',7'-tetrachlorofluorescein and N,N,N',N'-tetramethylrhodamine derivatives. We observed that the fluorescence of the probe correlates with the amount of (1)O(2) present in solution. The red-light-activated "caged" oligodeoxyribonucleotides are stable duplexes, which consist of an unmodified strand and a blocker strand. The (1)O(2)-sensitive linker is introduced in the interior of the blocker strand. Upon exposure of the duplex to red light in the presence of In(3+)(pyropheophorbide-a) chloride, the linker is cleaved with formation of the unstable duplex structure. This product decomposes spontaneously, releasing the unmodified strand, which can bind to the complementary target nucleic acid. This uncaging reaction is high-yielding. In contrast, previously reported visible-light-activated reagents are uncaged inefficiently due to competing reactions of sulfoxide and disulfide formation.     

Novel K/Mn phosphate hydrates,K2Mn3(H2O)2[P2O7]2 and KMn(H2O)2[Al2(PO4)3]: hydrothermal synthesis and crystal chemistry

Two novel K/Mn phosphate hydrates, namely, dipotassium trimanganese dipyrophosphate dihydrate, K₂Mn₃(H₂O)₂[P₂O₇]₂, (I), and potassium manganese dialuminium triphosphate dihydrate, KMn(H₂O)₂[Al₂(PO₄)₃], (II), were obtained in the form of single crystals during a single hydrothermal synthesis experiment. Their crystal structures were studied by X‐ray diffraction. Both new compounds are members of the morphotropic series of phosphates with the following formulae: A₂M₃(H₂O)₂[P₂O₇]₂, where A = K, NH₄, Rb or Na and M = Mn, Fe, Co or Ni, and AM²⁺(H₂O)₂[M³⁺₂(PO₄)₃], where A = Cs, Rb, K, NH₄ or (H₃O); M²⁺ = Mn, Fe, Co or Ni; and M³⁺ = Al, Ga or Fe. A detailed crystal chemical analysis revealed correlations between the unit‐cell parameters of the members of the series, their structural features and the sizes of the cations. It has been shown that a mixed type anionic framework is formed in (II) by aluminophosphate [(AlO₂)₂(PO₄)₂]_∞ layers, with a cationic topology similar to the Si/Al‐topology of the crystal structures of feldspars. A study of the magnetic susceptibility of (II) demonstrates a paramagnetic behaviour of the compound.     

States of the 12N Nucleus with Increased Radii

The differential cross sections for the ¹²C(³He, t)¹²N reaction leading to formation of the 1⁺ (ground state), 2⁺ (0.96 MeV), 2⁻ (1.19 MeV), and 1⁻ (1.80 MeV) states of ¹²N are measured at E(³He) = 40 MeV. The analysis of the data is carried out within the modified diffraction model and distorted wave Born approximation. Increased rms radii have been obtained for the ground, 2⁻ (1.19 MeV), and 1⁻ (1.80 MeV) states. We revealed that ¹²B, ¹²N, and ¹²C in the isobaric analogue states with T = 1, and spin-parities 2⁻ and 1⁻ have increased radii and exhibit properties of neutron and proton halo states.

     

Search for Exotic States in 13C

JETP Letters - New experimental data on the inelastic scattering of α-particles on 13C at $$E(\alpha ) = 65$$ and 90 MeV with the excitation of the $$1{\text{/}}2_{3}^{ - }$$ state are...     

Synthesis of biologically active derivatives of 2-aminobenzothiazole

Chemistry of Heterocyclic Compounds - The minireview considers the current trends in the synthesis of some biologically active compounds based on 2-aminobenzothiazole. The presented information...     

Variation of the Antioxidative Defense in Elaeis guineensis Jacq. Facing Bud Rot Disease in the Coastal Area of Ecuador

Elaeis guineensis Jacq. has gained a reputation in the food industry as an incredible crop capable of supplying the world’s largest edible oil production. In Ecuador, an important oil palm-producing country, this crop is affected in a high percentage by the bud rot disease, which is responsible for palm death. The main objective of the investigation was dedicated to understanding the palm defense mechanism facing bud rot disease, translated in the induction of reactive oxygen species, activation of defensive machinery comprising enzymatic and non-enzymatic antioxidative components, secondary metabolites, carotenoids accumulation in the palm during all stages of disease infection. For this, a survey was conducted in different oil palm plantations in the Esmeraldas province, one of the most representative for its highest incidence of bud rot disease. The survey completed DPPH, FRAP, ABTS, and other spectrophotometric analyses to underline the biochemical, biological, and physiological palm response front of bud rot incidence. The palm defense strategy in each disease stage could be represented by the phenolic compound’s involvement, an increment of antioxidant activity, and the high enzymatic activity of phenylalanine ammonia-lyase (PAL). The results of the investigation made understandable the palm defense strategy front of this disease, respectively, the antioxidative defense and the palm secondary compounds involved.     

Synthesis of phosphocyclic 2,2′,7,7′-tetrahydroxydinaphthylmethane derivatives

Two types of phosphocyclic derivatives were synthesized by phosphorylation of 2,2′,7,7′-tetrahydroxydinaphthylmethane with triamidophosphites: triphosphorus containing compounds with a phosphocine ring and two acyclic diamidophosphite fragments, and tetraphosphorus-containing macrocycles with a 24-membered ring and two eight-membered phosphorus rings. It was shown that interaction of triphosphorus compounds with resorcinarene gives tetraphosphorus macrocycles.     

Formation of lanthanide ion networks by orientation of the mesophases of their complexes in magnetic fields

A complex of a Tm(III) perfluoroalkylsulsphate with salicylaldimine Schiff's base was synthesized and its liquid crystallinity characterized by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction. An additional phase transition was detected. 2D or 3D anisotropically-organized media were obtained by cooling of the lanthanide complex from different phases in an applied magnetic field. A huge positive magnetic anisotropy was observed for the resulting material.