Search results for "DISCOVERY"

Die Synthese vono-Acylamino-β-dimethylamino-propiophenonen. 4. Mitt.: Synthese der primären Mannich-Basen

1972

Das durch Umsetzung von 2-Acetamino-β-dimethylamino-propiophenon (IVb) mit Dibenzylamin darstellbare 2-Acetamino-β-dibenzylamino-propiophenon (XXVII) kann hydrogenolytisch mit tels Palladium-Aktivkohle in die entsprechende, nur am aromatischen Stickstoff acetylierte primare Mannich-Base ubergefuhrt werden. In analoger Weise sind auch in 5-Stellung substituierte Derivate des 2-Acetamino-β-amino-propiophenons (XXVIII) zuganglich. Synthesis of 2-Acylamino-β-amino-propiophenones 2-Acetamino-β-dibenzylamino-propiophenone (XXVII) and its derivatives, substituted in 5-position, can be synthetized by reaction of 2-acetamino-β-dimethylamino-propiophenone (IVb) with dibenzylamine. By hydrogenolysis i…

Antikonvulsiva, 1. Mitt. Thiocarbamoylbutyroguanamine

1986

Durch Anlagerung von Butyroguanamin (1) an die Isothiocyanate 2a-c sind die Thiocarbamoylbutyroguanamine 3a-c zuganglich. Auf dem Wege der Acylierung von 3 sind unsymmetrisch substituierte Butyroguanamine 4 erhaltlich. Unter den neu entwickelten Verbindungen zeichnet sich insbesondere 3c durch antikonvulsive, fungizide und die Magensauresekretion hemmende Wirkungen aus. Anticonvulsivic Agents, I: Thiocarbamoylbutyroguanamines The thiocarbamoylbutyroguanamines 3a-c are accessible by addition of butyroguanamine (1) to the isothiocyanates 2a-c. Unsymmetrically substituted butyroguanamines 4 are obtainable by acylation of 3. Among the newly prepared compounds, 3c in particular exhibits anticonv…

2014

Carbon-centered radicals represent highly useful reactive intermediates in organic synthesis. Their nucleophilic character is reflected by fast additions to electron deficient C=X double bonds as present in iminium ions or cationic heterocycles. This review covers diverse reactions of preformed or in situ-generated cationic substrates with various types of C-radicals, including alkyl, alkoxyalkyl, trifluoromethyl, aryl, acyl, carbamoyl, and alkoxycarbonyl species. Despite its high reactivity, the strong interaction of the radical’s SOMO with the LUMO of the cation frequently results in a high regioselectivity. Intra- and intermolecular processes such as the Minisci reaction, the Porta react…

Highly Diastereoselective Michael Reaction of (S)‐Mandelic Acid Enolate. Chiral Benzoyl Carbanion Equivalent Through an Oxidative Decarboxylation of …

2002

The reaction of the lithium enolate of the 1,3-dioxolan-4-one derived from optically active (S)-mandelic acid and pivalaldehyde with α,β-unsaturated carbonyl compounds proceeds readily to give the corresponding Michael adducts in good yields and high diastereoselectivity. Subsequent basic hydrolysis of the acetal and oxidative decarboxylation of the α-hydroxyacid moiety provides chiral 2-substituted 1,4-dicarbonyl compounds with very high enantiomeric excesses.

Enantioselective synthesis of 2-substituted-1,4-diketones from (S)-mandelic acid enolate and α,β-enones

2006

[EN] An approach for the synthesis of chiral non-racemic 2-substituted-1,4-diketones from (S)-mandelic acid and ¿,ß-enones has been developed. The reaction of lithium enolate of the 1,3-dioxolan-4-one derived from optically active (S)-mandelic acid and pivalaldehyde with ¿,ß-unsaturated carbonyl compounds proceeds readily to give the corresponding Michael adducts in good yields and with high diastereoselectivities. The addition of HMPA (3 equiv) reverses and strongly enhances the diastereoselectivity of the reaction. A change in the reaction mechanism from a lithium catalyzed to the one where catalysis has been suppressed by coordination of HMPA to lithium is proposed to explain these resul…

A new electrophilic addition to acetylenes. Synthesis of 1,2-iodofunctionalized olefins

1986

Abstract Acetylenes react with bis(pyridine)iodo(I) tetrafluoroborate ( 1 ) in the presence of a wide variety of nucleophiles (F, Cl, Br, I, SCN, pyridine, OAc, anisole, H) to give 1,2-iodofunctionalized olefins ( 4 ).

A new and versatile method for iodofunctionalization of 1,3-dienes

1986

Abstract We wish to report the reactions of conjugated dienes with I(py) 2 BF 4 . This simple and general method allows the regiospecific 1,2-addition of iodine and a nucleophile to terminal dienes and the 1,4-addition to internal dienes.

1,4-regioselective iodofunctionalizations of 1,3-butadiene

1988

Abstract Addition reactions of benzene and acetonitrile to 1,3-butadiene are described. This new iodofunctionalization process proceeds “via” iodonium ion-allylic cation equilibrium and gives regioselectively 1,4-adducts, which can be alternatively obtained by acid treatment of the 1,2-derivative 8 .

Fine-needle biopsy of parathyroid adenomas

1986

High-resolution real-time sonography was performed in 15 cases of clinically and chemically suspected primary hyperparathyroidism and in 20 patients with different thyroid nodules. The suspected enlarged parathyroid glands and the thyroid nodules were percutaneously punctured under sonographic control. Concentrations of parathyroid hormone, human thyroglobulin, and human calcitonin were measured in the aspirate, and immunocytology was performed. The mean concentration of the aspirated parathyroid hormone in the parathyroid glands was 4,013.6 pmol/l +/- 4,519 (SD) as compared with 14.9 pmol/l +/- 8.7 in the thyroid nodules. Thyroglobulin was present in the aspirated fluid of parathyroid aden…

Hypermineralocorticoidism and hypertension

1971

Die mit Hypokaliamie, Uberproduktion von Mineralocorticoiden (Aldosteron und/oder Corticosteron und Desoxycorticosteron) und Aktivitatsanderungen des Renin-Angiotensinsystems einhergehenden Hochdrucksformen werden beschrieben. Sie lassen sich nach willkurlich gewahlten biochemischen Kriterien in drei Gruppen einteilen: a) Hypermineralocorticoidismus mit Reninsuppression und Aldosteronismus, b) Hypermineralocorticoidismus mit Reninund Aldosteronsuppression und c) Hypermineralocorticoidismus mit erhohtem Plasmarenin und Aldosteronismus. Jede dieser Gruppen besteht aus mehreren Syndromen, die sich durch ihr adrenocorticales Sekretionsmuster und/oder ihre morphologischen Nebennierenrindenverand…