Chemistry

Macrokinetics for chemical transformation of ethylene glycol into glyoxal (including side-reactions) as
well as 2D heterogeneous mathematical model were suggested. Numerical results obtained using this
model were compared with the experimental data obtained at lab-scale and pilot reactor, and showed
good correlation. It was shown that due to catalyst activity change it is possible to manage the process
selectivity with respect to glyoxal in diffusion mode. The optimal value of catalyst activity providing the
highest process selectivity can be found.

The product of acetaldehyde and ammonia
reaction, namely, 2,4,6-trimethyl-1,3,5-hexahydrotriazine trihydrate,
was synthesized and identified using a combination of
experimental (NMR spectroscopy, IR spectroscopy, melting
point determination) and DFT-based theoretical approaches. A
reaction mechanism was proposed. The reaction was shown to
proceed via the formation of aminoalcohol, imine, and geminal
diamine intermediates accompanied by cyclization of these
species. The calculation results allowed us to build a potential
energy surface of the acetaldehyde and ammonia interaction
and determine the most energetically favorable pathway to yield
acetaldehyde ammonia trimer. The reaction product was found in an energy minimum (−53.5 kcal/mol).

Mono-, di-, and tetramethylglycolurils were synthesized, isolated, and purified. For the first time, the cis- and the transisomers
of N,N-dimethylglycoluril were isolated as individual substances by semi-preparative HPLC method. The structures of the synthesized compounds were confirmed by 1H NMR, 13C NMR, and HR–HPLC–MS. The EI mass spectra of individual substances were obtained by the GC–MS. Retention and resolution of N-methyl glycolurils were investigated in the
reversed-phase HPLC mode for different stationary phases: C18,
SB–Aq, and Luna 5u PFP(2). The retention of N-methylglycolurils depended on the amount of CH3 groups and distance between the CH3 groups in the structure. The stationary phases provided different selectivity for glycoluril and its N-methyl derivatives due to different shape selectivity. Complete separation of the N-methyl derivatives of glycoluril was achieved in 4.5 min on the stationary phase with pentafluorophenyl propyl ligand in a gradient mode.

Ferrocenylalkyl nitro-imidazoles (4a-h, 5a-h) were prepared via the regiospecific reaction of the a-(hydroxy)alkyl ferrocenes, FcCHR (OH) (1aeh; Fc¼ ferrocenyl; R ¼ H, Me, Et, Pr, i-Pr, Ph, ortho-Cl-Ph,
ortho-I-Ph), with nitro-imidazoles in aqueous organic medium (H2O-CH2Cl2) at room temperature in the presence of HBF4, within several minutes in good yields. X-ray structural data for racemic (R,S)-1-N-
(benzyl ferrocenyl)-2-methyl-4-nitroimidazole (5f) were determined. The resulting enantiomers were resolved into enantiomers by analytical HPLC on modified amylose or cellulose chiral stationary phases.
The viabilities of 4b, 4d, 5b, 5c in vitro, and in experiments in vivo antitumor effects of 1-N-ferrocenylethyl-4-nitroimidazole (4b) against murine solid tumor system Ca755 carcinoma were evaluated.

5,6,7,8-Tetrafluoroquinoxaline (1) and its previously unknown derivatives (2–8) were synthesized from glyoxal and polyfluorinated 1,2-diaminoarenes (10–17) obtained by reduction of corresponding 2,1,3-
arenothiadiazoles (including new ones 21 and 22). The thiadiazoles were prepared from polyfluorinated Ar–NH2 via Ar–N55S55N–SiMe3 (34–37) and their fluoride-induced nucleophilic ortho-cyclization. New approaches to Ar–N55S55N–SiMe3 based on interaction between polyfluorinated Ar–N55SCl2 (32) and LiN(SiMe3)2, and between ArN(SiMe3)Li and Me3Si–N55S55O, were tried together with our previous synthetic method based on reaction of Ar–N55S55O with Me3SnLiN(SiMe3)2. New polyfluorinated 2,1,3-arenoselenadiazoles (26–28) were prepared from corresponding diamines and SeO2 and 26 also from the diamine and SeCl4. Compounds synthesized were characterized by multinuclear NMR (particularly 1H, 19F, 77Se), compounds 1, 2, 4, 7, 8, 16 (salt with 2 HCl), 19, 26, 28 and 32 by single-crystal X-ray diffraction, and quinoxalines 1–8, thiadiazole 22 and selenadiazoles 27 and 28 by UV-vis and fluorescence techniques.

This work shows for the first time the use of tetrakis(hydroxymethyl)glycoluril in the melt N-methylenation reactions of arylamines, based on the ability of tetrakis(hydroxymethyl)glycoluril to eliminate a formaldehyde molecule. It was shown by HPLC that tetrakis-
(hydroxymethyl)glycoluril under the studied conditions is subject to dehydroxymethylation processes

In the present paper, the effect of glyoxal on the gel formation within the adhesive systems based on urea-formaldehyde (UF) resins is shown. A reduction of formaldehyde content in wood-based panels by decreasing the formaldehyde/urea molar ratio in the UF resins leads to increasing of the UF resin gel time, and impairing the qualitative characteristics of the UF-based wood materials. Glyoxal is shown to speed up the crosslinking of the macromolecules as well as significant reduction of gel time of adhesive composition. The first reason is the result of reaction between glyoxal and ammonium ion leading to protons releasing. Another reason is that glyoxal and its interaction products react with macromolecules of the UF resin forming a three-dimension cross-linked structure. The gel time and the pot life of the UF resin are measured by the oscillatory viscometer. Formation of the UF cross-linked resin structure with glyoxal and a curing catalyst (ammonium sulfate) is studied using dispersion Raman scattering spectroscopy. Particleboards (PB) are produced using different amount of glyoxal and formaldehyde/urea molar ratio in the UF resin. The properties are evaluated according to the European Standards and include density, internal bond, thickness swelling moisture content and formaldehyde content.

Due to high multi-functionality, bicyclic ureas of octoic type (also known as glycolurils) are used in many applications, including the manufacturing of slow-release nitrogen fertilizers, additives for paints and coatings, polymer stabilizers, psychoactive drugs, intermediates for synthe-size supramolecular compounds such as cucurbiturils and bambusurils and other practically im-portant products. Among the glycoluril derivatives, N,N,N,N-tetraacetic derivative named as tetraacetylglycoluril occupies a special place and is produced as a fine chemical and used as a bleaching activator (as an example for perborates) in detergents. Tetraacetylglycoluril as a parent compound of acylated glycolurils finds its application as a bleaching activator in detergents and successfully competes with its counterpart tetraacetylethylenediamine. The chemistry of tetraacetyl-glycoluril presented in the literature is fragmentary and unsystematized, and does not allow receiv-ing a deep understanding on the chemical properties and fields of application of this available compound. We suppose that the availability and multi-functionality of the tetraacetylglycoluril makes it possible to realize its synthetic potential. In the present article the main processes to pro-duce tetraacetylglycoluril, its chemical properties and application fields are discussed in details. Chemical properties of tetraacetylglycoluril are described in details for reactions of hydrolysis, nu-cleophilic substitution, N- and O-acylation of amines and alcohols. It is noteworthy that tetraacetyl-glycoluril can be successfully used as a soft acylating agent for biogenic organic substrates and as a building block to synthesize new supramolecular compounds.

The availability and multifunctionality of allantoin makes it extremely attractive to unlock the synthetic potential on the basis thereof, especially for the needs of the pharmaceutical industry. Numerous publications on the allantoin chemistry are scarce, nonsystematic in nature and do not allow a deep understanding of the methods for its preparation and its chemical properties. In order to close this gap, the present review integrates the systematic data on the methods for the allantoin synthesis and the study of its chemical properties as well as the areas of allantoin practical application. In the present work, the methods most widely used in preparative practice to produce allantoin from the carbonyl compounds and urea are considered, and the ways of transformation of a number of nitrogen-containing heterocycles under the influence of various reagents leading to the target product are presented. The main chemical properties of allantoin are shown in hydrolysis reactions, complexa-tion with organic and inorganic substrates, interactions with nucleophilic reagents, in chemoluminescence processes. In some cases, when the unconventional methods for the allantoin synthesis are given and allantoin transformations are considered, the mechanisms of the formation of final compounds are shown. A systematic material on the preparation methods and the chemical properties of allantoin can serve as a reliable navigator for those specialists who aim at manufacturing of allantoin-based practically important substances. Based on the integrated data it is pointed out that allantoin can be successfully used as a basic azaheterocycle to manufacture a wide range of new compounds, including bioactive ones.

Most of the known methods for the synthesis of heterocyclic compounds have disadvantages, such as a long reaction time and aggressive conditions. We have developed a new, rather simple and efficient method for the synthesis of a number of glycoluryls and hydantoins in water using a etidronic acid (HEDP) as "Green catalyst." So, for the first time, the condensation reaction of ureas with 1, 2-dicarbonyl compounds was carried out in the presence of HEDP. Also based on NMR studies, a chemism of these reactions, which is stepwise, is proposed. It has been established that the optimal conditions for the synthesis of glycoluryls and hydantoins using HEDP are: temperature 80 C-90 C, 40-20 minutes, and the ratio of urea and HEDP is 1:1. In all cases, the remaining aqueous filtrate containing HEDP after the reaction can be reused for other cycles synthesis of glycoluril and other compounds, because HEDP is not converted during the reaction.

The paper discusses the results of X-ray diffraction studies of 2,4,6,8-tetraazabicyclo[3.3.0.]octane-3,7-dione (glycoluril) and its derivatives. Geometrical characteristics of glycoluril derivative molecules are analyzed depending on the type of the substituent and the formation of hydrogen bonds in crystals.

Установлено, что тетраацетилгликолурил под действием мочевины, некоторых N-замещенных мочевин и бензилиденбисмочевины в кислотно-катализируемых условиях подвергается только бисдезацетилированию с образованием сини анти-региозамещенных N,N-диацетилгликолурилов, а не N-ацетилированию, как это ранее было показано в аналогичной реакции для ряда ароматических и гетероциклических аминов. В ходе проведенных отдельных экспериментов выявлено отсутствие самостоятельного влияния органических растворителей при кипячении в течение нескольких часов (спирты, диоксан, тетрагидрофуран, диметилсульфоксид) на реакции дезацетилирования тетраацетилгликолурила, так как в этих условиях исходный субстрат оставался неизменным. На основании данных ЯМР-спектроскопии, путем сопоставления интегральных интенсивностей метиновых и ацетильных протонов гликолурильных фрагментов, найдено, что бисдезацетилирование тетраацетилгликолурила в изученных условиях происходит региоселективно с подавляющим преобладанием анти-N...