Naturally Occuring Thiophenes

Bohlmann, Ferdinand; Zdero, Christa

doi:10.1002/9780470187234.ch3

Cited by 30 publications

(6 citation statements)

References 131 publications

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“…Thiophenes are important motifs in several bioactive natural products as well as pharmaceuticals . Moreover, thiophene derivatives also serve in organic material science due to their structural rigidity and distinct electronic properties .…”

Section: Introductionmentioning

confidence: 99%

A Thioannulation Approach to Substituted Thiophenes from Morita–Baylis–Hillman Acetates of Acetylenic Aldehydes

2013

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A new protocol has been developed for the synthesis of substituted thiophenes under mild and metal-free reaction conditions via the base-promoted thioannulation of Morita-Baylis-Hillman acetates of acetylenic aldehydes with potassium thioacetate involving a tandem allylic substitution/deacetylative 5-exo-dig-thiocycloisomerization. The obtained products provide an entry to 4H-thieno[3,2-c]chromene and thieno[3,2-c]dihydroquinoline.

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Section: Introductionmentioning

confidence: 99%

A Thioannulation Approach to Substituted Thiophenes from Morita–Baylis–Hillman Acetates of Acetylenic Aldehydes

2013

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“…Thiophene (c-C 4 H 4 S) is a five-membered heterocyclic compound, containing four carbon atoms and one sulfur atom in the ring. The delocalization of electron lone pairs on sulfur, in the conjugated π system, makes thiophene behave like an aromatic compound. , This electron delocalization makes thiophene and thiophene-based materials and polymers an important building block entity for manufacturing various materials, showing unusual electronic and optical properties. − …”

Section: Introductionmentioning

confidence: 99%

“…Recently, thiophene and its derivatives, especially halogen substituted, have received great attention in many fields. These are important organic reagents, which can be used in natural product synthesis, drug design, molecular recognition, and the preparation of new materials with defined properties. ,− The substituted halothiophenes have wider applications in organic chemistry, biochemistry, pharmaceutical chemistry, and material chemistry, including the preparation of polythiophenes. − At the molecular level, these substituted thiophenes, which have linear conjugated systems, represent the simplest models of molecular wires, contributing to the emergence of the concepts of molecular electronics and logic …”

Section: Introductionmentioning

confidence: 99%

Photodissociation Dynamics of Halogenated Thiophenes at 235 nm: A Resonance Enhanced Multiphoton Ionization-Time-of-Flight (REMPI-TOF) Study

et al. 2012

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The photodissociation dynamics of halogen-substituted thiophenes, namely, 2-chlorothiophene and 2-bromo-5-chlorothiophene, has been studied in a supersonic molecular beam around 235 nm, using resonance enhanced multiphoton ionization (REMPI) time-of-flight (TOF) technique, by detecting the nascent state of the primary halogen atoms. A single laser has been used for excitation of halothiophenes, as well as for the REMPI detection of photoproducts, namely, chlorine and bromine atoms, in their spin-orbit states X((2)P(3/2)) and X*((2)P(1/2)). We have determined the translational energy distribution, the recoil anisotropy parameter, β, and the spin-orbit branching ratio, for chlorine and bromine atom elimination channels. State-specific TOF profiles are converted into kinetic energy distributions, using a least-squares fitting method, taking into account the fragment anisotropies, β(ι). The TOF profiles for Cl, Cl*, Br, and Br* are found to be independent of laser polarization; i.e., the β is well characterized by a value of ~0.0, within the experimental uncertainties. For 2-chlorothiophene, we have observed two components for the Cl and only one component for the Cl* atom elimination channel in the translational energy distributions. The average translational energies for the fast and the slow components of the Cl channel are 3.0 ± 1.0 and 1.0 ± 0.5 kcal/mol, respectively. For Cl*, the average translational energy is 3.5 ± 1.0 kcal/mol. For 2-bromo-5-chlorothiophene, we have observed only one component for Cl, Cl*, Br, and Br* in the translational energy distributions. The average translational energies for the Cl and Cl* channels are 3.5 ± 1.0 and 5.0 ± 1.0 kcal/mol, respectively, whereas the average translational energies for the Br and Br* channels are 2.0 ± 1.0 and 3.5 ± 1.0 kcal/mol, respectively. The energy partitioning into the translational modes is interpreted with the help of various models, such as impulsive and statistical models. The ΔH(f)(298) value for 2-chlorothiophene has been estimated theoretically to be 23.5 kcal/mol.

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“…It was as early as in 1826 when the first naturally occurring acetylenic compound was isolated from an Artemisia species. 16 Since then, a plethora of naturally occurring acetylenes produced by plants, fungi, sponges or bacteria have been discovered. 17,18 Many of those compounds display useful biological activity, which has made them worthwhile synthetic targets in pharmaceutics and propelled the search for improved methodologies to prepare the polyyne functional group.…”

Section: Introductionmentioning

confidence: 99%

The Fritsch–Buttenberg–Wiechell rearrangement: modern applications for an old reaction

Jahnke

Tykwinski

2010

Chem. Commun.

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The Fritsch-Buttenberg-Wiechell rearrangement of carbene/carbenoid intermediates has evolved into a valuable synthetic methodology for the preparation of polyyne structures. Various synthetic routes toward the formation of the corresponding precursors, alkynyl-substituted dibromoolefins, have been developed. Additionally, the scope of this methodology is expanded significantly by the development of functional group-tolerant one-pot procedures. The preparation of various polyynes up to the octa- and decaynes is, thus, possible on a scale that enables thorough physico-chemical characterization. Hence, series of polyynes have been investigated by, e.g., UV-vis, IR- and Raman spectroscopy, as well as X-ray crystallography. These investigations give unique insight into the structural characteristics of longer polyynes and hint to the structure of carbyne.

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Naturally Occuring Thiophenes

Cited by 30 publications

References 131 publications

A Thioannulation Approach to Substituted Thiophenes from Morita–Baylis–Hillman Acetates of Acetylenic Aldehydes

A Thioannulation Approach to Substituted Thiophenes from Morita–Baylis–Hillman Acetates of Acetylenic Aldehydes

Photodissociation Dynamics of Halogenated Thiophenes at 235 nm: A Resonance Enhanced Multiphoton Ionization-Time-of-Flight (REMPI-TOF) Study

The Fritsch–Buttenberg–Wiechell rearrangement: modern applications for an old reaction

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