S. N. Ivanov

Photochromic dihetarylethenes. 7. Synthesis of bis(thienylazoles), photochromic analogs of diarylethenes

Procedures for the synthesis of 4,5-bis[2,5-dimethyl(3-thienyl)]-1,3-azoles based on 1,2-bis[2,5-dimethyl(3-thienyl)]-2-hydroxyethan-1-one, 2-chloro-1,2-bis[2,5-dimethyl(3-thienyl)]ethan-1-one, and 1,2-bis[2,5-dimethyl(3-thienyl)]ethane-1,2-dione were developed. Dithienylethenic compounds in which the thienyl rings are linked through the azole rings exhibit photochromic properties.

Photochromic dihetarylethenes. 11. Synthesis and photochromic properties of diarylethenes containing furan or furopyrimidine bridges

Procedures were developed for the synthesis of substituted bis(2,5-dimethyl-3-thienyl)furans based on 1,2-bis(2,5-dimethyl-3-thienyl)-2-hydroxyethanone. Dithienylethene structures in which the ethene fragment is involved in the furan or furopyrimidine system possess photochromic properties and their open forms exhibit fluorescence.

Photochromic dihetarylethenes. 17. Synthesis and photochromic properties of dithienylethenes containing new heterocyclic bridging fragments

Procedures were developed for the synthesis of substituted bis(2,5-dimethyl-3-thienyl)ethenes containing the imidazol-2-one, 1,3-dioxol-2-one, or 1,3-oxazol-2-one fragments as ethene bridges. These compounds were demonstrated to exhibit the photochromic properties. The cyclic forms of some imidazolone and oxazolone photochromes possess high thermal stability. The structure of photochromic 4,5-bis(4-acetyl-2,5-dimethyl-3-thienyl)-3-methyl-2,3-dihydro-1,3-oxazol-2-one was established by X-ray diffraction analysis. The molecule adopts an anti-parallel conformation similar to that of perfluorocyclopentene-bridged dithienylethenes.

Behavior of benzoins and hydroxy ketones in acid medium: II. Reactions of 1,2-bis(2,5-dimethyl-3-thienyl)-2-hydroxy-ethan-1-one with N,S-binucleophiles in trifluoroacetic acid

Abstract1,2-Bis(2,5-dimethyl-3-thienyl)-2-hydroxyethan-1-one reacts with thioamides, thiosemicarbazides, and methyl hydrazinecarbodithioate in trifluoroacetic acid to give the corresponding thiazole, thiadiazine, and pyrazole derivatives, respectively.

Reactions of cyclic enaminoketones with benzylidenemalononitriles. Synthesis of new fused heterocyclic systems containing the 1,4-dihydropyridine fragment

The reactions of cyclic enaminoketones with benzylidenemalononitriles were examined and a new procedure was developed for the synthesis of fused heterocyclic systems containing the 1,4-dihydropyridine ring, viz., thienopyrimidoquinolines and furopyrimidoquinolines. The characteristic features of the reactions and the structures of the resulting compounds were investigated.

Taenia sp. in human burial from Kan River, East Siberia

We present an arhaeoparasitological analysis of a unique burial from the Neftprovod II burial ground in East Siberia, which dated from the Bronze Age. Analysis of a sediment sample from the sacral region of the pelvis revealed the presence of Taenia sp. eggs. Because uncooked animal tissue is the primary source of Taenia, this indicated that the individual was likely consuming raw or undercooked meat of roe deer, red deer, or elk infected with Taenia. This finding represents the oldest case of a human infected with Taenia sp. from Eastern Siberia and Russia.

Traditional Living Habits of the Taz Tundra Population: A Paleoparasitological Study

An excavation of the Vesakoyakha II–IV and Nyamboyto I burial grounds was conducted during the 2014 field season, and soil samples from intact burials dating from the 19th and 20th centuries, respectively, were analyzed to determine interactions between parasites and host/vectors. Considering the discovery of Diphyllobothrium sp. and Taenia sp. eggs in soil samples from the pelvic region, diphyllobothriasis was the most frequent helminthic infection among the Taz Nenets. The Nyamboyto Nenets mainly consumed uncooked fish, while the Vesakoyakha Nenets had a bigger variety in food choices, including reindeer meat. Nenets children were given raw fish from early childhood. The paleoparasitological results corroborate rare ethnographic records about the consumption of uncooked reindeer cerebrum which led to beef tapeworm helminthiases. This is the first parasitological report of helminthic diseases among the Taz Nenets, and, as such, it provides insight into their subsistence activities and food patterns and broadens our understanding of their health condition.

Behavior of Benzoins and Hydroxy ketones in Acid Media: I. Reaction of 1-Aryl-2-(2,5-dimethylthiophen-3-yl)-2-hydroxyethanones with Thiols in Trifluoroacetic Acid

Reactions of 1-aryl-2-(2,5-dimethylthiophen-3-yl)-2-hydroxyethanones with thiols in trifluoroacetic acid lead to formation of substituted 1-aryl-2-(2,5-dimethylthiophen-3-yl)-2-sulfanylethanones.

Opisthorchiasis in infant remains from the medieval Zeleniy Yar burial ground of XII-XIII centuries AD

We present a paleoparasitological analysis of the medieval Zeleniy Yar burial ground of the XII-XII centuries AD located in the northern part of Western Siberia. Parasite eggs, identified as eggs of Opisthorchis felineus, were found in the samples from the pelvic area of a one year old infant buried at the site. Presence of these eggs in the soil samples from the infant’s abdomen suggests that he/she was infected with opisthorchiasis and imply consumption of undercooked fish. Ethnographic records collected among the population of the northern part of Western Siberia reveal numerous cases of feeding raw fish to their children. Zeleniy Yar case of opisthorchiasis suggests that this dietary custom has persisted from at least medieval times.

Trichuris trichiura in the mummified remains of southern Siberian nomads

Abstract The identification of parasites in ancient human remains can address questions of past health, disease, mobility and mortuary customs. Archaeoparasitological evidence from Russia is, however, almost absent. This study presents the first such evidence in the form of a helminth infection in a mummified individual from the southern Siberian site of Doge-Bary II, the burial ground of a nomadic Iron Age community. Despite the removal of the intestines as part of the mummification procedure, the residual eggs of Trichuris trichiura, a non-indigenous species of whipworm, were detected. This evidence provides the first confirmation of prehistoric contact between southern Siberian nomads and distant agricultural areas, such as China and Central Asia.