Rearragnement of 1-allyloxy-2-allylthio-4-methyl-benzene TO 2,4-dimethyl-6-allyl-7 hydroxy-2,3-dihydrobenzothiophene

1-Allyloxy-2-allylthio-4-methylbenzene rearranges in NN-diethylaniline at 215°C with migration of allyloxy and allylthio groups to form 2,4-dimethyl-6-allyl-7-hydroxy-2,3dihydrobenzothiophene.M. V. Lomonosov State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 480–482, 1994. Original article submitted March 5, 1994.     

Mechanism of the thio-claisen rearrangement of 3-methylallyl phenyl sulfide

The thio-Claisen rearrangement of isomeric 3- and 1-methylallyl phenyl sulfides was investigated. It is demonstrated that the thio-Claisen rearrangement of the 3-methyl isomer is preceded by its thioallyl rearrangement to the 1-methyl isomer. The latter undergoes thio-Claisen rearrangement to o-(3-methylallyl)thiophenol, which is cyclized to 2-ethyl-2,3-dihydrobenzothiophene and 2-methylthiochroman under the reaction conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1191–1194, September, 1981.     

Alkylation of anionoid intermediates in the reaction of benzofuran with lithium in hexametapol

It is shown that the principal pathway in the reaction of benzofuran with a solution of lithium in hexametapol is opening of the furan ring of benzofuran to give a dilithium derivative. Mono- and dialkylation products are formed when the reaction mixture is treated with alkylating agents. It was established by the use of alkylating agents with different degrees of hardness that the oxygen atom is a softer polarizable center than the sp-hybridized carbanion center.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 22–23, January, 1978.     

Rearrangement of allyl thienyl sulfides to allylthiophenethiols

It is shown that the rearrangement of allyl 2-thienyl and allyl 3-thienyl sulfides in various solvents at 89–136°C gives the corresponding allylthiophenethiols, which can subsequently undergo transallylation with the starting sulfide and cyclization to thienodihydrothiopyrans and methyldihydrothienothiophenes. The energy of activation of the rearrangement of both isomeric sulfides is 19 kcal/mole. The pK_a values of thiophenyl and some thiols of the thiophene series were determined, and it was established that the acidities of the allylthiophenethiols do not have a decisive effect on their ability to undergo cyclization.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 186–189, February, 1978.     

Transformations of 2-methylthiacyclobutane in the presence of aluminum oxide

The transformations of 2-methylthiacyclobutane at 150–350 °C in the presence of -Al₂O₃ samples with different aprotic acidities were investigated. It was established that the sulfide undergoes isomerization via two pathways, viz., with ring expansion to a five-membered ring and with opening at one C—S bond to give an unsaturated thiol. An experimental confirmation of the consecutive formation of hydrogen sulfide from a one-ring sulfide through a step involving the formation of an unsaturated thiol was obtained for the first time. The transformations are realized as a result of both ionic and polymerization-depolymerization processes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 184–187, February, 1982.     

Reactions of alkyl furfuryl ethers and sulfides with n-butyllithium

The direction of the reaction of alkyl furfuryl ethers and sulfides with n-butyllithium is in agreement with the results of basic H-D exchange in the same compounds: In the case of the ethers H-D exchange and metallation take place primarily in the free a position of the furan ring, whereas in the case of the sulfides these reactions take place primarily at the methylene group of the side chain located between the sulfur atom and the furan ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 744–746, June, 1984.     

Researches on imidazoles

A number of derivatives of imidazo [5, 1-b] thiazole, imidazo [5, 1-b] thiazoline, and imidazo [5, 1-b] thiazolid-3-one are synthesized by cyclizing 2-alkyl-4(5)-nitro-5(4)-formylmethyl (-ketoalkyl-,-hydroxyethyl-, and carboxymethyl) mercaptoimidazoles.For Part XXVI see [18].     

Crystal Structure of Cl-Deficient Analogue of Taseqite from Odikhincha Massif

An eudialyte group mineral, found in pegmatites of the Odikhincha massif (the northern part of the Siberian platform), has been investigated using X-ray diffraction, IR spectroscopy, and Raman spectroscopy. The mineral is characterized by a high strontium content and a low chlorine content. It has a trigonal unit cell with the following parameters: a = 14.2700(6) Å and c = 30.057(1) Å; V = 5300.6(1) ų; sp. gr. R3m. The structure has been refined to R = 0.047 in the anisotropic approximation of atomic displacements using 1697F > 4σ(F). The idealized formula (Z = 3) was found to be Na₁₂Sr₂Ca₆Fe ₃ ²⁺ Zr₃NbSi₂₅O₇₂(OH,O)₄Cl(Н₂О)_0.2. The chemical composition and structure of this mineral are close to those of taseqite; however, it differs from the holotype sample by a low chlorine content and peculiarities of cation distribution over basic structure sites. A comparative analysis of strontium-rich eudialytes has revealed their important crystallochemical feature: selective concentration of strontium in the N4 site. Thus, taseqite, along with heterophyllosilicates, may play a role of strontium concentrator in agpaitic pegmatites.     

Formation of 2,3-disubstituted benzofurans in the reaction of dichlorocarbene with a 2-alkylthiomethylbenzofuran

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 129–130, January, 1990.     

Influence of the diameter of monolithic capillary columns on their gas chromatography characteristics

Divinylbenzene polymer monolithic capillary columns were prepared on the basis of capillaries 0.01 to 0.53 mm in diameter. Separation properties of the columns were investigated with the use of a test mixture of light hydrocarbons. The permeability and C parameter in the Van Deemter equation were determined for all the columns. For the most part, the columns had similar characteristics: permeability was in the range (2.2 ± 0.2) × 10^?9 cm², with parameter C in the range (0.7 ± 0.2) × 10^?3 s (with n-butane as a sorbate). It was thus established that capillary diameter has only a slight effect on the efficiency of monolithic capillary columns (unlike packed capillary columns and microcolumns, whose properties, according to the literature data, depend strongly on the column diameter). The difference in properties between the narrowest monolithic column (capillary diameter 0.01 mm) and the others is explained by column overloading.