4,810 research outputs found
N,N-(dimethylamino)-2-pyrrolidinones from the rearrangement of N-allyl-N ',N '-dimethyl-2,2-dichlorohydrazides promoted by CuCl-N,N,N ',N '-tetramethylethylendiamine
No full textTreatment of N-allyl-N¢,N¢-dimethyl-2,2-dichlorohydrazides with CuCl/TMEDA in ethyl acetate35is a mild and easy method for preparing N-(dimethylamino)-2-pyrrolidinones. As the N-N bond in the lactamproducts can be easily and efficiently cleaved, this makesN-dimethylamino protection an attractive alternative toN-benzylic protection
The synthesis of functionalised beta- and gamma-lactams by cyclisation of enamides using copper(I) or ruthenium(II)
No full textCyclisation of a variety of halo-enamides with copper(I) or ruthenium(II) complexes has been investigated. The regioselectivity of the radical cyclisation, which can proceed via either a 4-exo or 5-endo pathway, to form beta- or gamma -lactam products respectively, is determined by the nature of the metal oxidant and the reaction conditions. Thus, whereas copper(I)bipyridine reactions give predominantly gamma -lactams, the use of copper(I)/TMEDA or dichlorotris(triphenylphosphine)ruthenium(II) affords mainly beta -lactams. (C) 2001 Elsevier Science Ltd. All rights reserved
Metal-catalysed radical cyclisations leading to N-heterocycles: new approaches to gabapentin and pulchellalactam
No full textThe copper(I) or ruthenium(II)-mediated radical cyclisation of halo-amides has been utilised to afford functionalised pyrrolidinones via 5-endo-trig or 5-exo-trig radical cyclisation pathways. This methodology has been applied to novel and concise syntheses of the anti-epileptic drug gabapentin and the biologically active natural product pulchellalactam
Breakthrough in the alfa-perchlorination of acyl chlorides
No full textThe preparation of -perchloroacyl chlorides, from reaction of the corresponding unfunctionalized acyl halides with chlorine, was efficiently achieved under base-catalysis, using a tetraalkylammonium chloride as catalyst. The process is solvent-free and the procedure is easy, inexpensive, and suitable for scale-up
CuCl-catalyzed radical cyclisation of N-a-pechloroacyl-ketene-N,S-acetals: a new way to prepare disubstituted maleic anhydrides
No full textThe discovery that cycloalkanes can form thermomorphic systems with typical polar organic solvents has
led to the development of less-polar electrolyte solutions. Their mixing and separation can be regulated
reversibly at a moderate temperature range. The phase switching temperature can be controlled by
changing the solvent compositions. While biphasic conditions are maintained below the phase switching
temperature, conductive monophasic conditions as less-polar electrolyte solutions are obtained above
the phase switching temperature. After the electrochemical transformations, biphasic conditions are
reconstructed below the phase switching temperature, facilitating the separation of cycloalkane where
hydrophobic products or designed hydrophobic platforms are selectively partitioned. Several polar organic
solvents, including acetonitrile, methanol, and pyridine, can be used in this system according to the
requirement of the reactions
Isrogrogidda Falka Af-soomaaliga: Aragti ku aadan Midaynta Qoraalkiisa
No full textQoraagu wuxuu diraasad ku sameeyey sidii loo midayn lahaa af Soomaaliga qoraaal ahaan loo adeegsada. Gaar ahaan wuxuu diiradda saarayaa sidii loo midayn lahaa qaababka isrogrogga falalka oo haatan loo adeegsado siyaabo aan midaysanayn.In questo articolo, l'autore analizza e avanza una proposta relativamente alla standardizzazione del somalo scritto, in particolar modo delle forme di coniugazione dei verbi somali che attualmente non sono scritte in modo omogenea.In this article, the author analyzes and provides a proposal about the standardization of written Somali, in particular relating to verb conjugation forms whose orthography still differs today.Cabdirashid M. Ismaaciil, Cabdalla C. Mansuur, Saynab A. Sharci (eds.
Coastal Research and its Economic Justification
No full textProper and thorough planning of coastal engineering projects is discussed and the economie justification of research work indicated. Examples are given concerning navigational problems, coastal protection problems, and harbor sediment problems.KWP-collectio
Midaynta iyo Horumarinta Af-soomaaliga
No full textQoraagu wuxuu maqaalkan ku falanqaynayaa arrimo ku saabsan midaynta af Soomaaliga qoran, oo dadka qaarkood ay ku doodaan in ay dhibaato ka taagantahay, iyagoo u aanaynaya kala duwanaanta lahjadaha Soomaaliyeed iyo farta af Soomaaliga oo aan xasillayn. Qoraha oo soo bandhigayaa in arrimahaasu aanu sax ahayn, wuxuuna muujinayaa caqabadaha dhabta ah ee hortaagan houmarinta af Soomaaliga: afku wuxuu la'yahay dawlad si rasmi ah u adeegsato, weerar ba'anna waxaa ku haya af Ingiriisiga, xagga ereyadana nabaadguur xooggan ayaa ku dhacaya, gaar ahaan ereyada la xiriira dhaqanka Soomaaliyeed.L'autore, in questo articolo, analizzando la questione della lingua somala scritta, cerca di illustrare che la situazione del somalo standard non è cosi problematica come a detta di alcuni somali, specialmente, nell'ortografia e nella differenza tra i dialetti, ma il problema somalo è bensì riscontrabile in altri fattori: la mancanza di un stato che continui ad adottare il somalo come lingua ufficiale, l'estinzione di tantissimi vocaboli in disuso, nonché la forte influenza dalla lingua inglese.The author in this article, in analysing the written somali language, wants to show the somali standard situation is not so bad, like some Somalis say, especially in orthography and in vernaculars difference. In spite of, the somali language problem is recognisable in some others factors: lack of state that usually chooses somali language as official language, extinction of many terms in disuse and also the strong influence of English.Cabdirashid M. Ismaaciil, Cabdalla C. Mansuur, Saynab A. Sharci (eds.
Om inloppet ifrån Östersjön : till SöderTelje eller Egelsta wiken
No full textAuthor: Nathanael Gerhard af Schultén.Dated: "Carlberg den 12 Januari 1806."Digital reproduction, The National Library of Finland, Centre for Preservation and Digitisation, MikkeliA description of the Baltic Sea.TravelEuropeanaSchultén, Nathanael Gerhard af (1750-1825
Dwing als gebiedsontwikkelaar een duidelijke opdracht af
No full textTerwijl de context waarin gebiedsontwikkelaars werken alleen maar complexer wordt, ziet Co Verdaas, hoogleraar gebiedsontwikkeling, een aanhoudende neiging om keuzes vooruit te schuiven of te verhullen. Hij geeft zes tips om gebiedsontwikkelaars in hun kracht te zetten. “Zonder escalatie geen resultaat zou het devies moeten zijn.”Practice Chair Urban Area Developmen
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