Academic literature on the topic 'Acetophenone|ent'

Yacon [Smallanthus sonchifolia (Poepp. et Endl.) H. Robinson], a native plant of the Andes, belongs to the family Compositae (Asteraceae) and it represents a traditional crop of the original population of Peru used in traditional medicine. A major portion of tuberous root biomass is composed of water (> 70% of fresh weight). Saccharides, especially oligo-fructans, form 70–80% of dry weight, protein content ranges between 0.3% and 3.7%. Fructooligosaccharides of inulin type b (2®1), mainly oligomers (GF2–GF16), are known for their ability to keep the colon healthy. Yacon sweetness is predominantly caused by fructose, which is by some 70% sweeter than sucrose. Other oligosaccharides are 1-kestose and nystose. Diabetics and persons suffering from digestive problems are recommended to consume yacon because its sugars are not available from the small intestine. The mean tuberous root composition per 100 g of fresh matter is 81.3, 13.8, 0.9, 1.0, 0.1 and 1.1 g of water, saccharides, fibre, proteins, lipids and ash, respectively. Mean mineral contents per 100 g of fresh matter are 334, 34, 12, 8.4, 0.4 and 0.2 mg of potassium, phosphorus, calcium, magnesium, sodium and iron, respectively. Vitamins B1, B2, C, b-carotene and polyphenols in the same weight are present at mean concentrations 0.07, 0.31, 5.0, 0.13 and 203 mg, respectively. Yacon can be considered an industrial crop, particularly as a source of inulin. The used forms are flour, syrup, extract from tuberous roots and moreover leaf extract for the preparation of yacon infusion with hypoglycaemic effect. In yacon leaves di- and sesquiterpenes with protective effects against insects are present, among them mainly ent-kaurenic acid (ent-kaur-16-en-19-oic acid) and its derivative – 15-a-angeloyloxy-ent-kauren-19-oic acid 16-epoxide. Other components are polyphenolic antioxidants, esp. hydroxycinnamic acids and chlorogenic acid. A new antifungal melampolide – sesquiterpene lactone named sonchifolin, as well as three known melampolides, polymatin B, uvedalin and enhydrin, were isolated from leaf extracts of yacon. Three major phytoalexins were isolated: 4’-hydroxy-3’-(3-methylbutanoyl)acetophenone, 4’-hydroxy-3’-(3-methyl-2-butenyl)acetophenone and 5-acetyl-2-(1-hydroxy-1-methylethyl)benzofuran.

Titanium(II) bis(tetrahydrofuran) 1, generated by the treatm ent of TiCl4 in THF with two equivalents of n-butyllithium at -78 °C, has been found to form carbon-carbon bonds with a variety of organic substrates by reductive coupling. Diphenylacetylene is dimerized to exclusively (E,E)-1,2,3,4-tetraphenyl-1,3-butadiene; benzyl bromide and 9-bromofluorene give their coupled products, bibenzyl and 9,9'-bifluorenyl, as do benzal chloride and benzotrichloride yield the 1,2-dichloro-1,2-diphenylethanes and 1,1,2,2-tetrachloro-1,2-diphenylethane, respectively. Styrene oxide and and cis-stilbene oxide undergo deoxygenation to styrene and fra/«-stilbene, while benzyl alcohol and benzopinacol are coupled to bibenzyl and to a mixture of tetraphenylethylene and 1,1,2,2-tetraphenylethane. Both aliphatic and aromatic ketones are smoothly reductively coupled to a mixture of pinacols and/or olefins in varying proportions. By a choice of experimental conditions either the pinacol or the olefin could be made the predom inant product in certain cases. The reaction has been carried out with heptanal, cyclohexanone, benzonitrile, benzaldehyde, furfural, acetophenone, benzophenone and 9-fluorenone. In a remarkable, multiple reductive coupling, benzoyl chloride is converted into 2,3,4,5-tetraphenylfuran in almost 50% yield. The stereochemical course of two such couplings, that of diphenylacetylene to yield exclusively (E,E)-1,2,3,4-tetraphenyl-l,3-butadiene and that of acetophenone to produce only racemic-2,3-diphenyl-2,3-butanediol, is interpreted to conclude that the couplings proceed via two electron transfer pathways (TET) involving titanium (IV) cyclic intermediates of the titanirene and the oxatitanacyclopropane type, respectively.

Ce memoire est consacre a la synthese d'electrodes modifiees (em) par des films de polypyrroles fonctionnalises par des complexes polypyridiniques de metaux de transition et a leur application en electrocatalyse en milieu aqueux. Une partie de ce travail de recherche a ete orientee vers l'amelioration de l'efficacite, de la stabilite et de la selectivite de films de polymeres derives des complexes rh(l)#2(cl)#2#+ (l=2,2'-bipyridine ou 1,10-phenanthroline substituees), vis-a-vis de l'hydrogenation electrocatalytique (hec) de substrats organiques insatures. En particulier, nous avons montre que des complexes contenant des ligands chiraux sont capables de catalyser, en phase homogene et supportee, l'hec enantioselective de l'acetophenone. Le mecanisme de ces hec a pu etre precise avec l'etude electrochimique des complexes du type rh#i#i#i(x)(y)(l)(p)#2#+ (x, y = h ou cl, p = phosphine tertiaire) en solution homogene et en phase polymerique. La mise en evidence de l'electrogeneration des complexes hydrure a partir des complexes chlorure correspondants et l'activite electrocatalytique de ces complexes vis-a-vis de l'hydrogenation de substrats organiques a confirme la participation d'intermediaires hydrure dans le mecanisme de l'hec. Enfin nous avons developpe une technique, qui avait ete peu utilisee jusqu'a present, pour elaborer des films de poly(pyrrole-m#i(diene)(l)#+ (m = rh ou ir, diene = cod, nbd ou ed, l = 2,2'-bipyridine), par complexation in situ de complexes precurseurs m#i(diene)cl#2 dans des films de ligands pre-deposes sur electrode par electropolymerisation. Ce procede nous a permis de synthetiser des films de complexes du rh(i) et de l'ir(i) qui ne peuvent etre obtenus par electropolymerisation directe, a cause de leur instabilite redox. Ce travail presente les conditions d'elaboration de ces em, leurs etudes electrochimiques et spectroscopiques, ainsi que leur application en hec

Le travail se divise en deux grandes parties : la premiere concerne la preparation d'aryl-6 imidazo(2,1-b) thiazoles substitues en 3 par des chaines de type acetate d'ethyle, aroylmethyle. (beta -hydroxy beta -aryl)ethyle te arylethyle. Pour ce faire, il a ete necessaire de preparer les amino-2 thiazoles corespondants substitues par ces memes chaines en 4 afin de las opposer a des acetophenones omega -bromees. L'influence des substituants presents est discutee en vue d'aprehender l'evolution des reactions. La seconde partie concerne des essais en tant que fongistatiques et/ou immunostimulants des composes preparees. Il ressort que les aminothiazoles sont plus interessants que les imidazothiazoles auusi bien sur l'inhibition de croissance de mycelium (epidermophyton) ou de germination des spores (candida, aspergillus) que sur la stimulation du lymphocyte t humain

Etude de la reduction electrochimique de l'acetophenone, l'oxyde de mesityle et l'ethylideneacetone en milieu aqueux en presence d'agents de surface anioniques (laurylsulfate de sodium), d'agents de surface cationiques (bromure de benzyltrimethylammonium et bromure de cetyltrimethylammonium) et d'agents de surface non ioniques (brij 35 et poly(oxyethylene))