Comparative research on promising energetic 1,3-diazinane and 1,3-oxazinane structures

The additional carbon centers in 1,3-diazinane and 1,3-oxazinane enable them to covalently bonded geminal-explosophoric groups, leading to unique energetic properties when compared with their homologous energetic structure like RDX. In this paper, a concise synthesis and comparative studies towards 1,3,5-(trinitro1,3-diazinane-5-yl) methyl nitrate and (3,5-dinitro-1,3-oxazinan-5-yl) methyl nitrate (TNOP), two energetic 1,3-diazinane/1,3-oxazinane based promising explosive molecules, are reported. The new germinal nitro/nitroxy explosophoric moieties in the 1,3-diazinane and 1,3-oxazinane frameworks lead to novel structural and energetic properties, which have been investigated through both experimental and computational methods. Densities of the obtained compounds are 1.83 g·cm^?3 and 1.72 g·cm^?3, respectively, along with the detonation velocities of 8714 m·s^?1 and 8112 m·s^?1. The energetic properties of TNNP are comparable to those of RDX. Meanwhile, the low melting point (105 °C) and excellent insensitivity (IS﹥60 J, FS﹥360 N) of TNOP make it an ideal material for the preparation of melt-cast explosives.     

Synthesis of 1,3-dihalo-1,3-dioximino-2-propanones

1,3-Dihalo-1,3-dioximino-2-propanones (Hal=Cl or Br), which had been difficult to prepare or unreported, were obtained by the nitrosation of 1,3-dihalo- and 1,3-dihalo-1-oximino-2-propanones by nitrosylsulfuric acid in concentrated H₂SO⁴.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 506–509, February, 1991.     

Oxidation reactions of 1,3-diphenylpropane-1,3-dione

The free radical scavenging properties and possible antioxidant activity of 1,3-diphenylpropane-1,3-dione (1) are reported. Pulse radiolysis technique was employed to study the one-electron oxidation of 1 with various radicals viz. CCl₃O₂ ^•, N₃ ^• and^•OH in homogeneous aqueous solution. All these radicals reacted with 1 under ambient conditions at almost diffusion controlled rates producing transient species with an absorption maximum around 420 nm that decayed at first order rates. The transient absorption peak was shifted in the case of CCl₃OO^• radical reaction with 1 due to change in the polarity of the medium. Formation of a stable product with a broad absorption band starting from 400 nm and cut off at 230 nm was observed in the oxidation of 1 with^•OH and^•N₃ radicals. In a biological system also, 1 showed significant inhibitory activity against Fe²⁺-mediatedlipidperoxidation. Based on these observations, a suitable mechanism for the oxidation of 1 has been proposed.     

Dissociative electron capture by 1,3-dithiolanes and 1,3-dioxalanes

A study was carried out on dissociative electron capture by 1,3-dithiolanes and 1,3-dioxalanes. The mechanisms for the fragmentation pathways of the negative ions differ significantly between the oxygen- and sulfur-containing compounds. The (M-H)^– ions are formed with excess internal excitation energy.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 208–210, January, 1990.     

AM1 study of conformations of oxocane and 1,3-dioxocane

Summary AM1 semi-empirical SCF MO calculations are reported for important conformations of oxocane (1) and 1,3-dioxocane (2). The boat-chair conformation of1 (BC-1) is found to be the most stable form, whereas the crown family conformation is calculated to be 3.7 kJ·mol^–1 less stable. The boat-boat form of1 is 15.9 kJ·mol^–1 less stable thanBC-1. The boat-chair conformation of2 (BC-1,3) is calculated to be the most stable form of 1,3-Dioxocane. The crown-family conformation and the boat-boat geometry of this compound are 4.2 and 8.3 kJ mol^–1 less stable thanBC-1,3.

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AM1-Rechnungen zu den Konformationen von Oxocane und 1,3-Dioxocan

Zusammenfassung Die wesentlichen Konformationen von Oxocan (1) und 1,3-Dioxocan (2) wurden mittels semiempirischer AM1-Rechnungen (SCF MO) untersucht. Die Wanne-Sessel-Konformation von1 (BC-1) ist am stabilsten; Konformationen aus der Klasse der Kronen sind um 3.7 kJ·mol^–1 energiereicher. Die Wanne-Wanne-Konformation von1 ist um 15.9 kJ·mol^–1 instabiler alsBC-1. Die Wanne-Sessel-Konformation von2 (BC-1,3) ist das stabilste Konformer von 1,3-Dioxocan. Kronenkonformationen und Wanne-Wanne-Geometrien sind um 4.2 und 8.3 kJ·mol^–1 energiereicher alsBC-1,3.

     

Microwave-assisted rapid electrophilic fluorination of 1,3-dicarbonyl derivatives with Selectfluor

A microwave-assisted fluorination method for 1,3-dicarbonyl compounds using Selectfluor^® has been developed. 2-Monofluorinated products can be obtained in high yield in neutral reaction conditions with addition of 1 eq. of Selectfluor^®. Treatment of 1,3-dicarbonyls with 3 eq. of Selectfluor^® in the presence of tetrabutylammonium hydroxide (TBAH) as the base results in the formation of 2,2-difluorinated derivatives only.     

A novel method for the determination of total 1,3-octanediols in apple juice via 1,3-dioxanes by solid-phase microextraction and high-speed gas chromatography

In this work, a novel, simple and fast method based on solid-phase microextraction (SPME) followed by high-speed gas chromatography (HSGC) was developed for the analysis of total 1,3-octanediols in apple juices by means of derivatization reaction to volatile 1,3-dioxanes. The derivatization reaction, SPME conditions, glycosidically bound fraction and 1,3-nonanediol as a surrogate standard were studied. The formation of 1,3-dioxanes from 1,3-diols was confirmed by GC–MS. The method was validated obtaining a regression coefficient (r²) of 0.9996, precisions between 0.3 and 9.8%, extraction recoveries in the range 94.7–112.2% and LOD of 2.9 μg l⁻¹. Experimental design has been employed in the optimization of extraction factors and robustness assessment. The method was applied to the analysis of 21 Asturian apple varieties finding a double reciprocal relationship between the concentrations of saturated and unsaturated 1,3-octanediol.     

Synthesis of the first 1,3-disubstituted 1,3-butadienyl heteroannular bridged [4]ferrocenophane

An unusual heteroannular cyclization of methyl 4-(((1′-(trimethylsilyl)ethynyl)ferrocenyl)ethynyl)benzoate (11) under the basic desilylation condition yielded 1,1′-(l-methoxy-3-(4′-(methoxycarbonyl)phenyl)-1,3-butadienylene)ferrocene (7), the first reported 1,3-disubstituted 1,3-butadienyl heteroannular bridged [4]ferrocenophane. Compound 7 has been characterized by elemental analysis, IR spectra, ¹H NMR spectroscopy and X-ray diffraction analysis. The electrochemical behavior has been investigated by cyclic voltammetry. The DFT calculation results of 7 are also reported.     

99mTc complexes of 1,3-propanedithiol derivatives

The labelling of 1,3-n alkylpropanedithiols and of 15-/1,3-dimercapto 2-propyl/ pentadecanoic acid by^99mTc has been performed by an exchange reaction with the hexachlorotechnetate ion^99mTcCl ₆ ^2– and by reduction of^99mTcO ₄ ^– with Sn/II/ in the presence of the ligand. The biological distribution of the exotechnetium complexes obtained by the latter method in mouse does not reveal a high tropism of these labelling compounds in relation to a particular tissue.     

1,3-thiazinediones and pyrimidinediones

The character of the effect of substituents on the position of the keto-enol equilibrium in 2-substituted 4,6-dioxodihydro-1,3-thiazines and the structure of the enol form are examined. 2-Phenyl-4,6-dioxodihydro-¹⁵N-1,3-thiazine was synthesized. It was shown by ¹³C NMR spectroscopy that the 2-phenyl-4-hydroxy-1, 3-thiazin-6-one structure corresponds to the enol form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 481–484, April, 1979.     

Synthesis of 1,3-bis(acetylacetonyloxy)- and 1,3-bis(benzoylacetonyloxy)benzene and their complexation with lanthanide ions

Claisen condensation of 1,3-bis(methoxycarbonylmethoxy)benzene with acetone and acetophenone afforded new chelating ligands consisting of two β-diketonate fragments, viz., 1,3-bis(acetylacetonyloxy)benzene and 1,3-bis(benzoylacetonyloxy)benzene, which are linked to each other through the resorcinol spacer. In the crystal, 1,3-bis(acetylacetonyloxy)benzene, unlike the starting ester, adopts a planar conformation and exists in the enol form. The acidities of these compounds and their complexation with lanthanide ions in aqueous ethanolic solutions were studied by pH-potentiometry. Depending on the concentration conditions and pH, the La³⁺, Gd³⁺, and Lu³⁺ ions form 1 : 1, 1 : 2, or 1 : 3 complexes with bis(β-diketones). The stability of the complexes increases as the atomic number of the lanthanide increases (La³⁺ < Gd³⁺ ≤ Lu³⁺). The complexation constants and selectivity of complexation substantially increase with increasing degree of deprotonation of the ligands, which indicates that both chelate groups of the ligands are simultaneously involved in coordination. The Ph substituents in bis(β-diketone) have a considerable effect on the composition and stability of complexes with lanthanide ions due to additional noncovalent inner-sphere interactions.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 614–622, March, 2005.     

Synthesis and structure of methyl-substituted 1,3-Dioxa-2-Silacylohexanes

The reaction of dimethyl(diethylthio)silane with 1,3-diols gave methyl-substituted 1,3-dioxa-2-silacyclohexanes.¹H and¹³C NMR spectroscopy were used to study the configuration and predominant conformations of the compounds studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 845–851, June, 1986.     

Mass-spectrometric study of 1,3-oxazacyclopentanes

The fragmentation of 1,3-oxazolidines under electron-impact and chemical-ionization (with methane as the gas reagent) conditions and the effect of the substituent in the 2 position of the heteroring on the stability of the molecular ions (M⁺) and on the character of the fragmentation of 1,3-oxazolidines were studied. It is shown that splitting out of an alkyl group from the 2 position is characteristic for electron impact. Processes involving alkylation and protonation with the formation of cluster ions are most characteristic for chemical ionization. In analogy with hydrolysis in the condensed phase, protonated 1,3-oxazolidine molecules split out an aldehyde molecule.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1031–1034, August, 1981.     

Cobalt(II) complexes with aminopolycarboxylate 1,3-pdta-type ligands: synthesis and characterization of trans(O6)-[Mg(H2O)6][CoII(1,3-pddadp)]·H2O

Starting from Ba₂(1,3-pddadp)·8H₂O (1,3-pddadp=1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate ion) and CoSO₄, a new hexadentate [Co^II(1,3-pddadp)]²⁻ complex has been prepared. The trans(O₆) geometry of this complex was confirmed by comparison of its i.r. and u.v.–vis. spectra with those of [Co^II(1,3-pdta)]²⁻ (1,3-pdta is the 1,3-propanediaminetetraacetate ion) and trans(O₆)-[Co^III(1,3-pddadp)]⁻ complexes of known X-ray crystal structure. Magnetic and electrolytic conductivity properties of these complexes have also been discussed.     

Synthesis and conformation of 2-silylethynyl-substituted 2,4,4,6-tetramethyl-1,3-dioxanes

Reaction of 2,4,4,6-tetramethyl-1,3-dioxanium perchlorate with lotsich reagents led to the synthesis of new silylethynyl-substituted 2,4,4,6-tetramethyl-1,3-dioxanes. According to the data of¹H and¹³C NMR and x-ray diffraction analysis, it was established that the 1,3-dioxane ring of the products obtained has the chair conformation.Kuban' State Technological University, Krasnodar 350072, Russia. Ufa State Oil Technical University, Ufa 450062, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 487–493, April, 1998.     

Synthesis of first nonannulated 1,2,3,4-tetrazine 1,3-dioxides

Thermolysis of o-diazidobenzotetrazine 1,3-dioxides was accompanied by cleavage of the C-C bond of the benzene ring to give nonannulated 1,2,3,4-tetrazine 1,3-dioxides. The structures of these first representatives of nonfused 1,2,3,4-tetrazines were confirmed by ¹³C and ¹⁴N NMR spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1589–1594, September, 2006.     

Ruthenium-Catalyzed Enantioselective Hydrogenation of 1,3-O-Disubstituted 1,3-Dihydroxypropan-2-ones

Optically active 1,3-O-disubstituted glycerols were obtained by enantioselective homogeneous hydrogenation of the corresponding 1,3-O-disubstituted 1,3-dihydroxypropan-2-ones with different Ru^II-binap complexes. The highest enantioselectivities were obtained with dimeric chloro-ruthenium complexes on the substrates bearing bulky trityloxy groups.     

31P-NMR-Daten heterocyclischer phosphine. Diastereomerenzuordnung an 1,3-Oxa-, 1,3-Aza- und 1,3-thiaphospholanen

The diastereomers of 16 1,3-oxa-, 1,3-aza- and 1,3- thiaphospholanes were assigned by means of the coupling constants ²J(P? C? H) and ³J(P? C? CH₃) and the linewidths of the ³¹P signals and ¹H chemical shifts of CH₃ groups. It is shown that the change in the ³¹P chemical shifts allows the estimation of the relative configuration in these compounds.     

Conductance behavior of electrolytes in 1,3-dimethylethyleneurea and 1,3-dimethylpropyleneurea at 25°C

1,3-Dimethylethyleneurea (DMEU) and 1,3-dimethylpropyleneurea (DMPU) were investigated as electrolytic media for a number of alkali metal and triisoamylbutylammonium salts via conductivity measurements over a concentration range of 1–100×10^–4 M at 25°C. The data were analyzed by the Fuoss-Shedlovsky, Fuoss-Onsager, and expanded Pitts equations. The limiting equivalent conductivities were about 1.5 times greater in DMEU than in DMPU, which is exactly the ratio of the viscosities. From the Fuoss-Onsager analysis, all salts studied were found to be essentially unassociated in both solvents. From the expanded Pitts equation the extent of association was small, but within a salt series the equation indicated that association decreased in the order iodides, thiocyanates > perchlorate > tetraphenylborates. Neither solvent differentiated between sodium and potassium ion mobilities, indicating a type of solvation behavior different from that in acyclic urea solvents such as tetramethyl- and tetraethylurea.     

Synthesis of 2-methylthio-4H-1,3-thiazines

2-Methylthio-4H-1,3-thiazines or their mixtures with 5-alkylidene-4H-5,6-dihydro-1,3-thiazines were obtained by cyclization of methyl N-3-oxoalkyldithiocarbamates in sulfuric acid. The regiospecificity of the reaction is determined by the structures of the starting compounds. The structures of the synthesized thiazines were confirmed by spectral methods of analysis (IR and ¹H and ¹³C spectroscopy).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–993, July, 1992.