Alexander A. Kondrasenko

Preparation of adamantyl derivatives of 1,4-; 1,6- and 1,7-dihydroxynaphthalenes and assignment of their NMR data

Adamantylation of dihydroxynaphthalenes with the hydroxyl groups on the same or different rings leads to compounds that are convenient starting materials in target‐oriented organic synthesis. Here, we report the 1H and 13C NMR assignments of eight 1‐adamantyl substituted derivatives of 1,4‐; 1,6‐ and 1,7‐dihydroxynaphthalenes. The data acquired and peculiarities of their molecular structure are useful for extrapolation for prompt characterization of compounds containing adamantane, dihydroxynaphthalenes or naphthoquinone units. Copyright

Adamantylation of polysubstituted arenes in trifluoroacetic acid

A reaction of 2,3-xylenol, 2,3-dichlorophenol, and 1,3-disubstituted benzenes with 1-adamantanol in trifluoroacetic acid leads to the corresponding monoand diadamantylated products.

Spectral assignment of new adamantane derivatives of 1,3-; 1,5-dihydroxy- and 1,5-dimethylnaphthalenes

1,3(I) and 1,5-dihydroxynaphthalens (II) as well as 1,5dimethylnaphthalene (III) are considered and investigated as template for building up various derivatives due to specific arrangement of the hydroxyl groups in its molecule (orthoandmetafor I; orthoand perifor II-III). Furthermore, some compounds containing resorcinol moiety exhibit depigmentation activity. A wide applications of adamantane derivatives allows to suggest that containing in its structure above-listed compounds I-III are of definite practical interest. Also it should be noted that aromatic compounds with an adamantane at the ortho-position to the hydroxyl groups are the key skeletons of synthetic retinoid analogues and supporting ligands of many homogeneous transition-metal catalysts. Moreover, recently much attention has been heeded to dearomatization reactions of aromatic and heteroaromatic compounds due to the highly reactive intermediates opportunities. Current report is an ongoing research of determination structure and features of adamantyl derivatives of dihydroxynaphthalenes by NMR spectroscopy. We describe here assignments of H and C NMR spectra of synthesized 1-adamantyl substituted compounds I-III. Additionally, previously defined patterns on the effect of OH-group in the orthoormetaposition to adamantane for its H and C NMR spectra have been confirmed on the basis of found spectral data. Such information can be useful for unambiguous interpretation of more sophisticated adamantyl derivatives of various naphthalene-units contain compounds, including their dearomatized derivatives.

Sulfation of Xylan with Chlorosulfonic Acid in 1,4-Dioxane

Sulfation of birch wood xylan by chlorosulfonic acid in 1,4-dioxane was studied for the first time. It has been found, that sulfation of xylan at a temperature of 20 °C for 5–6 hours makes it possible to obtain xylan sulfates with a degree of sulfur substitution 1.2. The optimum conditions of the reaction were found which allow to carry out the sulfation of xylan in milder conditions, as compared to known methods.

Synthesis of a Polyconjugated Polymer by Aldol Condensation of 2,5-Diformylfuran and Acetone

Pioneer synthesis of the product of aldol polycondensation between 2,5-diformylfuran and acetone is presented. The synthesis was accomplished by a direct reaction of diformylfuran and acetone in dimethyl sulfoxide with addition of aqueous sodium hydroxide as a catalyst. The fact of the aldol condensation occurrence and formation of the polyconjugated oligomers in this system is confirmed by 1H nuclear magnetic resonance and molecular absorption spectroscopy. Cannizzaro reaction plays a significant side process role in the studied system, leading to the loss of diformylfuran’s aldehyde groups and their inability to participate in polymer chain growth. A solid polymeric product of brown color was isolated with the yield of 28 % based on the initial diformylfuran. The solid product is insoluble (judging by the lack of coloration in liquid) in various tested solvents: water, 1,4-dioxane, dimethyl sulfoxide, acetone, chloroform, or 1,2-dichloroethane with trifluoroacetic acid mixed in different proportions. The presence of polyconjugated chains in the solid product is confirmed by electron spin resonance spectroscopy.

1H and 13C NMR spectral assignments of novel adamantyl and di-adamantyl derivatives of 1,2-dihydroxynaphthalenes, 1,8-dihydroxynaphthalenes, 2,3-dihydroxynaphthalenes, 2,6-dihydroxynaphthalenes and 2,7-dihydroxynaphthalenes

Despite the fact that since the discovery and development methods of preparation and isolation of various dihydroxynaphthalenes passed a long time, at present, each of the ten isomers continue to find more and more fields of application. Among them, 1,8-dihydroxynaphthalene and their derivatives take a special place because the peri-interactions in 1,8-substituted naphthalene skeleton have an influence on the physical and chemical properties of these compounds. In addition, currently, the properties of equatorenes [chiral polycyclic aromatic hydrocarbons containing bis(1-adamantyl) groups at the peri-positions] were actively investigated, and in the case of 1,8-bis(1-adamantyl)naphthalene, a distortion of an aromatic ring system was determined. Studies by NMR spectroscopy of various perieffects of naphthalene-containing compounds as well as analysis of influence of different-sized substituents on an aromaticity in hydroxynaphthalene system are an important topic in NMR literature. On the other hand, to date, numerous studies have reliably found that the adamantyl moiety generally increases the lipophilicity and positively modulates the therapeutic index of many experimental substances via various mechanisms. Many of these adamantylmodified compounds contain in their structure a variety of aromatic components. Beyond pharmaceutical chemistry, the most practical applications are discovered among hydroxyaromatic compounds with adamantane in the ortho-position relative to the hydroxyl groups. In addition, nuclear magnetic resonance properties of adamantane, its derivatives, and higher adamantalog series continue to be actively explored. We continue to describe adamantyl derivatives of the homologous series of different naphthalenediols and their NMR features. Previously, NMR spectra of 1,4-dihydroxynaphthalenes, 1,6-dihydroxynaphthalenes, 1,7-dihydroxynaphthalenes, 1,3dihydroxynaphthalenes and 1,5-dihydroxynaphthalenes with one or two adamantyl groups were characterized in details. In the current paper, we report complete H and C spectral assignments of mono-adamantyl and di-adamantyl-containing derivatives of 1,2-dihydroxynaphthalenes, 2,3-dihydroxynaphthalenes, 2,6-dihydroxynaphthalenes, 2,7-dihydroxynaphthalenes and 1,8-dihydroxynaphthalenes and 6-(1-adamantyl)-2,3-dihydroxynaphthalene synthesized previously. Some of these NMR spectra show expected features associated with the symmetry of the molecules. The obtained results, together with the data from previous articles, will expand information on the effect of bulky substituents on molecular constitution of hydroxynaphthalene systems and thus will be a useful resource in their structure elucidation by NMR spectroscopy.

Synthesis of Copolymers of Furandicarboxylic Acid, Ethylene Glycol, and Poly(Angelica Lactone)

This work demonstrates the possibility of creating biodegradable derivatives of poly(ethylene furandicarboxylate) by modification with poly(angelica lactone) chains. Block copolymers with the content of angelica lactone 33-50 mol. % (based on monomeric links) were obtained. Polymer yields were 60-70 %, and weight average molecular weights attained 36-45 kDa. The results of the polymers biodegradation are presented.

Synthesis and Anti-Knock Properties of Furfural Derivatives

Research octane numbers (RON) of the furfural diethyl acetal and furfurylamine solutions in straight-run gasoline were measured, and the liner dependences between the solution octane numbers and concentrations of furfural derivatives were found. Blending research octane numbers (BRON) for furfural diethyl acetal (106.0±3.8) and furfurylamine (193.5±7.7) are calculated. A novel method of syntheses of furfural diethylacetal by the direct interaction of the alcohol and the aldehyde is developed. To shift the reaction equilibrium a water vapour from gas phase over the reaction mass is removed by calcium oxide. Oxidative stability of the furfurylamine solutions in straight-run gasoline (test for induction period) was estimated. It corresponds to the GOST 2084-77 conditions at the furfurylamine concentrations less than 5 wt. % and exceeds value of 1000 min.