Akhnef A. Fatykhov

The microstructure of a series of diphenyl oxide–diphenyl sulfide (co)poly(arylene diphthalides) was studied by ¹³C NMR spectroscopy. The compositional heterogeneity of these polymers is determined not only by the ratio of aromatic fragments but also by the different stereochemistry of the diphthalide groups along the polymer chain. It was shown that analysis of the split signals of the bridgehead quaternary sp³-hybridized carbon atoms of the phthalide rings allows the content of homo- (AA and BB) and heterodiads (AB) of racemic and meso configurations in the (co)polymers to be estimated with satisfactory accuracy. The effect of synthesis conditions on the microstructure of (co)poly(arylene diphthalides) was investigated.

Heterocyclization of 3-[(alkylsulfanyl)methyl]pentane-2,4-diols with formaldehyde or propionaldehyde in boiling benzene in the presence of hydrochloric acid afforded new 5-[(alkylsulfanyl)methyl]-4,6-dimethyl-1,3-dioxanes. 1,3-Dioxanes are formed as a mixture of 4,6-cis- and 4,6-trans-isomers at a ratio of 1:0.3–0.9. In both isomers, the preferred chair conformation is realized. In the 4,6-cis-isomers of all 1,3-dioxanes, the methyl groups occupy a diequatorial position, and the alkylsulfanylmethyl substituent is in an axial orientation. In the 4,6-cis-isomer of 5-[(pentylsulfanyl)methyl]-2-ethyl-1,3-dioxane, the ethyl group is oriented equatorially. The 4,6-trans-isomers of 5-[(alkylsulfanyl)methyl]-1,3-dioxanes are characterized by a rapid conformational inversion chair–chair.

The acylation of bromobenzene with 3-(4-bromophenyl)-3-chlorophthalide gave 3,3-bis(4-bromo­phenyl)phthalide which was used as a monomer to obtain poly(diphenylenephthalide) {poly(3-oxo-1H2-benzofuran-1,1-diyl[1,1′-biphenyl]-4,4′-diyl} by polycondensation via the Ni(0)-catalyzed coupling. The described reaction provides a new synthetic approach to poly(arylenephthalides).

The co-polycondensation of 4,4′-bis(2-carboxybenzoyl)diphenyl oxide and 4,4′-bis(2-carboxybenzoyl)diphenyl sulfide pseudodichlorides was used to synthesize a series of (co)poly(arylenediphthalides) (PADP) with different molar ratios of the diphenyleneoxydiphthalide and diphenylenethiodiphthalide groups. The synthesized compounds were subsequently used as macroinitiators for the thermal polymerization of styrene. The effect of the structure of the initial PADP on the regularities of the process and the composition of the resulting copolymers was studied. To determine the contents of the diphenyleneoxydiphthalide and diphenylenethiodiphthalide fragments in PADP and arylenediphthalide–styrene copolymers, an original method was developed based on UV spectrophotometry of their colored sulfuric acid solutions.

A new approach has been developed for the synthesis of o-ketobenzoic pseudo-acid chlorides via dehalogenation of bromo-substituted cyclic o-ketobenzoic acid esters, followed by chlorination of the resulting diesters. Homocoupling of 2-(4-bromobenzoyl)benzoic acid methyl ester gave bis-pseudo-acid chloride con­taining a biphenyl fragment, which could not be obtained by the traditional method involving acylation of biphenyl and subsequent chlorination of the diacid thus formed owing to deactivation of the second para-position in the aromatic fragment. The proposed approach solves the problem of poor solubility of poly­phenylene diacids with more than three phenylene rings and makes it possible to synthesize a bis-pseudo-acid chloride with a quaterphenyl fragment.

The reaction of 3,5-dimethyl- and 5-methyl-3-(2-propyl)tetrahydro-4H-thiopyran-4-ones with formaldehyde without or in the presence of 0.1–0.5 equiv. sodium hydroxide produces 3,5-dialkyl-3-(hydroxymethyl)tetrahydro-4H-thiopyran-4-ones. 3,5-Dimethyltetrahydro-4H-thiopyran-4-one converted into 3,5-bis(hydroxymethyl)tetrahydro-2H-thiopyran-4-ol when the amount of base to 1 equiv increase. Under similar conditions 5-methyl-3-(2-propyl)tetrahydro-4H-thiopyran-4-one form 3-hydroxymethyltetrahydro-2H-thiopyran-4-ol, which cyclization to 7-oxa-3-thiabicyclo[4.2.0]octane.

Thermally initiated polymerization (120°С) of styrene in the presence of polyarylenephthalides containing the diphenyloxide fragments with different ratios of two adjacent (“head-to-head”) and single (“head-to-tail”) phthalide groups has been performed. Dependence of the polymerization system characteristics and reaction products composition on chemical structure and molecular mass of the starting copolyarylenephthalides, the reaction duration, and the mass ratio of the components in the mixture has been studied. The data of structural-morphological studies of the copolymers of different compositions are presented.

Previously unknown 5-alkyl-1,3-bis[(alkylsulfanyl)methyl]-1,3,5-triazinan-2-ones have been syn­thesized by three-component condensation of available N,N′-bis[(alkylsulfanyl)methyl]ureas with formaldehyde and primary amines in ethanol in the presence of sodium hydroxide or triethylamine. A one-pot four-component procedure has been proposed for the synthesis of the title compounds via successive thiomethylation of urea with a mixture of formaldehyde and alkanethiol and cycloaminomethylation of intermediate N,N′-bis[(alkyl­sulfanyl)methyl]ureas with formaldehyde and alkylamine.