Thesis--Universität Heidelberg, 1894.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

No description available.

Thesis (Ph. D.)--University of Washington. / Bibliography: l. [87]-89.

Bioassays of Flaveria linearis leaf extracts against bacterial phyllosphere isolates, E. coli and B. cereus demonstrated that the isolates were just as susceptible to thiophene phototoxicity as the other bioassay microorganisms. The isolates' lack of resistance suggested that phyllosphere thiophene concentrations were insufficient to generate a phototoxic microenvironment. Bacterial cell wall composition and detoxification mechanisms were important factors in resistance to phototoxicity. Additional pre- and post-infectional defense metabolites with selective phototoxic and antimicrobial properties were also detected in leaf extracts. Furthermore, HPLC analyses identified novel, water-soluble polyacetylenes which were also detected in other Flaveria species. UV spectroscopy and enzyme hydrolysis data permitted partial characterization of two species: i) a galactolipid derivative containing a diene-triyne acetylene and ii) a glucose-containing oligo/polysaccharide with a diene-triyne acetylene. These acetylenes may function as intermediates in thiophene biosynthesis or alternatively may be involved in storage and transportation.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

No description available.

Sulfur dioxide and 1,3-butadiene react to form a five-membered cyclic unsaturated sulfone. the 2,5-dihydrothiophene 1,1-dioxide (I). When treated with a base, I will isomerize to form the 2,3-dihydrothiophene 1,1- dioxide (II). The known procedures for the preparation of I and II have been improved. [see document for image of chemical structures] The 2,5-dihydrothiophene 1,1-dioxide (I) is the parent member of a large group of five-membered cyclic β-sulfones while the 2,3-dihydrothiophene 1,1-dioxide (II) is the parent member of the corresponding α-sulfones. Structurally, I contains a carbon-carbon double bond, a sulfone group and two α-methylene groups while II only has one α-methylene group but its carbon-carbon double bond is conjugated with the sulfone group. It is of considerable interest to study the chemical reactions of these two polyfunctional molecules to gain some information concerning the influence of the functional groups upon each other. Of further interest would be to compare the reactions of I and II since differences in chemical properties are to be expected since the α-sulfones have the double bond conjugated with the sulfone group while the β-sulfones do not. Bromine adds readily to I in aprotic media to give the 3,4-dibromotetrahydrothiophene 1,1-dioxide (V). The addition of bromine to II only occurs in a water solution to give the 2,3-dibromotetrahydrothiophene 1,1-dioxide (VII). The total lack of evidence of the addition of hydrogen halides to I or II was not expected. The electrophilic attack is hindered by the presence of the sulfone group. Free radical reactions using N-bromosuccinimide and 1,3-dibromo-5,5-dimethylhydantoin were employed with I and II. The expected allylic substitution of bromine in I at the 2 or 5 position and in II at the 3 position was not obtained but rather addition to the double bond of I and II occurred. The dehydrobromination reaction of 3,4-dibromo-tetrahydrothiophene 1,1-dioxide (V) has been improved to give better yields of the 3-bromo-2,3-dihydrothiophene 1,1- dioxide (XIII). A new compound, the 5-bromo-2,3-dihydrothiophene 1,1-dioxide (XVIIc), has been obtained from the dehydrobromination of the 2,3-dibromo-tetrahydrothiophene 1,1-dioxide (VII). The 3-bromo, 3-chloro and the 3-iodo-2,3-dihydrothiophene 1,1-dioxides were prepared through a series of reactions, the letter two for the first time. The 3-iodo-2,3-dihydrothiophene 1,1-dioxide (XIX) was prepared by treating the 3-bromo-2,3-dihydrothiophene 1,1- dioxide (XIII) with sodium iodide in acetone. The 3-chloro-2,3-dihydrothiophene 1,1-dioxide (XX) in turn was prepared by reacting the 3-iodo-2,3-dihydrothiophene 1,1-dioxide (XIX) with mercuric chloride in absolute ethanol. The infrared spectra of the above compounds were compared. Since the alpha hydrogens are acidic in the cyclic unsaturated sulfones, a thorough study of Grignard reagents with the 2,5-dihydrothiophene 1,1-dioxide (I) was made. A compound, believed to be a sulfinic anhydride, was obtained from the action of the 2,5-dihydrothiophene 1,1-dioxide (I) on ethylmagnesium bromide. Some evidence in support of this sulfinic anhydride is offered. A mechanism for the Grignard reactions is proposed from the data obtained. There was no evidence for condensation, alkylation or acylation reactions with the isomeric dihydrothiophene 1,1- dioxides. On the basis of the reactions studied, a clearer picture of the resonance structure of the 2,5-dihydrothiophene 1,1-dioxide (I) is obtained. / Ph. D.

In view of the increasing importance of thiophene derivatives as chemotherapeutic agents, it was considered of interest to apply the Reformatsky reaction to the synthesis of compounds containing the thiophene nucleus with the thought that these might serve as intermediates for further syntheses.

This thesis deals with the synthesis of new organicmaterials for electronic applications. Several new ring-formingmethods are employed to construct sulphur heterocycles: Tandemelectrophilic aromatic substitution and acid-catalyzedtransetherification of methoxythiophene, double electrophilicaromatic substitutions with ethane-1, 2-disulphenyl chloride,and also, the reaction of dienes with sulphur dichloride. Twonew condensed thiophenes have been incorporated in end-cappedoligothiophenes. An improvement of the synthesis of [3,2-b:2’, 3-d]thiophene is reported, with some attempts toincorporate it in oligomers. A synthesis of substitutednaphthalenes is also described. A new method of producingdisubstituted thiophenes from substituted butadienes anssulphur dichloride is employed in a new route to 3, 4-ethylenedioxythiophene, a very important monomer for conductingpolymers. Keywords :Organic Semiconductors, Thiophenes,Heterocyclic Synthesis, Dithienothiophene, Naphthalene,Ethylenedioxythiophene