Acetylenes thiophen

The polymers which have stimulated the greatest interest are the polymers of acetylene, thiophene, pyrrole and aniline, poly-p-phenylene, polyphenylvinylene and poly-l,6-heptadiyne. Of these materials polypyrrole has been available from BASF under the trade name Lutamer P160 since 1988. 

The thiophene analogue (51) of the natural antifeedant product tonghaosu has been prepared <96TL893>. Several acetylenic thiophene derivatives including 52 have been isolated from Blumea obliqua and characterized <96MI733>. 

Goncales CEP, Araldi D, Panatieri R B, Rocha J B T, Zeni G and Nogueira C W (2005), Antinociceptive properties of acetylenic thiophene and furan derivatives Evidence for the mechanism of action , Life Sciences, 76, 2221-2234. 

Thiophene is a sulphur-containing five-membered unsaturated heterocycle. The lone pair electrons of the sulphur are in the 35 orbital, and are less able to interact with the tt electrons of the double bonds. Therefore, thiophene is considered weakly aromatic. Acetylenic thiophene is found in some higher plant species. However, the thiophene ring is present in many important pharmaceutical products. 

Abstract Plasma polymerization is a technique for modifying the surface characteristics of fillers and curatives for rubber from essentially polar to nonpolar. Acetylene, thiophene, and pyrrole are employed to modify silica and carbon black reinforcing fillers. Silica is easy to modify because its surface contains siloxane and silanol species. On carbon black, only a limited amount of plasma deposition takes place, due to its nonreactive nature. Oxidized gas blacks, with larger oxygen functionality, and particularly carbon black left over from fullerene production, show substantial plasma deposition. Also, carbon/silica dual-phase fillers react well because the silica content is reactive. Elemental sulfur, the well-known vulcanization agent for rubbers, can also be modified reasonably well. 

An interesting application of acetylene coupling is the preparation of the per(acetylenated)thiophene (Equation 9) (88JOC2489). 

Acetylenic thiophene 2.9, found in some species of higher plants, is one of the few naturally-occurring thiophenes. However, the thiophene ring is used in several important pharmaceutical products, such as the penicillin antibiotic 2.10. 

A source gas inlet (acetylene-thiophene-hfc) B gas outlet C substrate D susceptor (graphite plate) E reaction tube (quartz,... 

In the presence of an acetylene, thiophene is produced. The addition occurs across the C-S bond of the thiirene, producing 2,3-substituted thiophenes. Photolysis of 4-methyl or 5-methyl thiadiazole yields only one thiophene, methylated in the 5-position, indicating a preferential addition on the unsubstituted side of the thiirene ring ... 

Naturally Occurring Thiophens.—Re-investigation of the polar fractions of the aerial parts of Centaurea ruthenica gave, amongst twenty new compounds, 5-hydroxymethyl-2-(3-hydroxypropynyl)thiophen. ° The investigation of two further Helichrysum species led to the isolation of three new unusual thiophen derivatives (137)—(139). New acetylenic thiophen derivatives such as (140) have been isolated from Cullumia setosa. ... 

A coupled OPLC-GC-MS system was used for the investigation of acetylenic thiophene derivatives in extracts of Tagete patula (72). The eluate from the layer, preseparated by the on-line OPLC method, was collected and injected to a GC-MS system. 

Downum, K.R., R.E.W. Hancock, and G.H.N. Towers Photodynamic Action on Escherichia coli of Natural Acetylenic Thiophenes, Particularly 5-(buten-l-ynyl)-2,2 -bithienyl. Photobiochem. Photobiophys. 6, 145 (1983). 

Downum, K.R., D.J. Keil, E. Rodriguez Distribution of Acetylenic Thiophenes in the Pectidinae. Biochem. Syst. Ecol. 13, 109 (1985). 

Downum, K.R., D. Provost, and L. Swain Acetylenic Thiophenes and C4 Photosynthesis Their Evolutionary Relationship in the Asteraceae. Bioact. Mol. (Chem. Biol. Nat.-Occurring Acetylenes Relat. Compd.) 7, 151 (1988). 

Rossi, R., Carpita, A., and A. Lezzi Palladium-Catalyzed Synthesis of Naturally-Occurring Acetylenic Thiophenes and Related Compounds. Tetrahedron 40, 2773 (1984). 

In the Asteraceae, acetylenes are widely distributed and structurally very diverse, including aliphatic acetylenes, acetylenic thiophenes, aromatics, isocoumarins and spiroacetal enol ethers (Table 5.1 and Figures 5.3,5.4 and 5.5). 

Further details about the biosynthesis of acetylenic thiophenes can be found in Bohlmann etal. (1973). 

Subsequently, small-band gap LC conjugated polymers [11] based on benzonoid and quinoid resonance structures were synthesized. Subsequently, ferroelectric LC (FLC) conjugated polymers [12] consisting of acetylene, thiophene, phenylene, or phenylenevinylene unit cell were synthesized in order to achieve highly quick response to an electric force field during macroscopic alignment. These FLC conjugated polymers, however, will not be further mentioned here and reviewed elsewhere. 

Naturally Occurring Thiophens.—The isolation of a terpenoid benzo[ ]-thiophen-4,7-quinone (200) from an acidophilic bacterium has been reported. New naturally occurring acetylenic thiophen derivatives have been isolated from Berkheya and Cullumia species and from Chrysanthemum macrotum. Several naturally occurring acetylenic thiophens have been synthesized. ... 

Naturally occurring Thiophens.—New acetylenic thiophen derivatives are still found in Nature, especially by Bohlmann and his group. From Santolina rosmarinifolia L., the compound (215) was isolated. From the South African family Arctotideae, genus Berkheya, twelve new thiophen-containing derivatives were isolated. One of these was believed to have structure (216), but by elegant synthesis of both (216) and an alternative structure (217), the latter was proved to be correct. Biosynthetic pathways... 

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