نتایج جستجو برای: chiral auxiliaries

تعداد نتایج: 38094  

Journal: :Chemical science 2015
Ryo Katoono Shunsuke Kawai Kenshu Fujiwara Takanori Suzuki

We describe a quantitative analysis of the complexation-induced inversion of a screw-sense preference based on a conformationally dynamic double-helix structure in a macrocycle. The macrocycle is composed of two twisting units (terephthalamide), which are spaced by two strands (1,3-bis(phenylethynyl)benzene), and is designed to generate a double-helix structure through twisting about a C2 axis ...

Journal: :Life sciences 1990
R S Hauck C Wegner P Blumtritt J H Fuhrhop H Nau

The stereoselectivity of the teratogenic activity of 2-ethylhexanoic acid (EHXA), a metabolite of the widely-used plasticizer di-(2-ethylhexyl)phthalate, was investigated. The enantiomers of EHXA were prepared via asymmetric synthesis with the aid of the chiral auxiliaries (R)- and (S)-1-amino-2-(methoxymethyl)pyrrolidine (RAMP, SAMP). The aqueous solutions of the sodium salts of (R)- and (S)-E...

Hedging academic claims has been recognized as one of integral pragmatic features of academic writing in which most EFL academic writers seem to face substantial problems. Explicit instruction has been proposed by some scholars as an effective approach to make EFL writers aware of the importance, different forms, and pragmatic functions of hedging devices some of which are polysemous and polypr...

Journal: :Organic letters 2000
M T Crimmins K Chaudhary

[formula: see text] Asymmetric aldol additions using chlorotitanium enolates of thiazolidinethione propionates proceed with high diastereoselectivity for the "Evans" or "non-Evans" syn product depending on the nature and amount of the base used. With (-)-sparteine as the base, selectivities of 97:3 to > 99:1 were obtained for the Evans syn products with 2 equivalents of base and for the non-Eva...

Journal: :Nature Communications 2021

Abstract To increase the reliability and success rate of drug discovery, efforts have been made to C( sp 3 ) fraction avoid flat molecules. -Rich enantiopure amines are most frequently encountered as chiral auxiliaries, synthetic intermediates for pharmaceutical agents bioactive natural products. Streamlined construction aliphatic has long regarded a paramount challenge. Mainstream approaches, ...

Journal: :Tetrahedron 2022

The palladium-catalyzed functionalization of alkenes is a versatile transformation in synthetic chemistry, but intermolecular processes often suffer from low reactivity and selectivity. Molecular tethers can be introduced to answer these challenges. They have been used successfully for decades, their installation removal normally required multi-step procedures. In this review, we will present p...

Journal: :Medical History 1975
R Heller

THE GREAT importance of medical auxiliaries in primary medical care and in community health schemes is now being increasingly recognized by those who are involved in the planning of health services for developed and developing countries alike. Schemes employing very large numbers of auxiliaries are already well established in Russia1 and in China.2 The major need for auxiliaries is, in the firs...

Journal: :Physical review letters 2011
T Aaltonen B Álvarez González S Amerio D Amidei A Anastassov A Annovi J Antos G Apollinari J A Appel A Apresyan T Arisawa A Artikov J Asaadi W Ashmanskas B Auerbach A Aurisano F Azfar W Badgett A Barbaro-Galtieri V E Barnes B A Barnett P Barria P Bartos M Bauce G Bauer F Bedeschi D Beecher S Behari G Bellettini J Bellinger D Benjamin A Beretvas A Bhatti M Binkley D Bisello I Bizjak K R Bland B Blumenfeld A Bocci A Bodek D Bortoletto J Boudreau A Boveia B Brau L Brigliadori A Brisuda C Bromberg E Brucken M Bucciantonio J Budagov H S Budd S Budd K Burkett G Busetto P Bussey A Buzatu C Calancha S Camarda M Campanelli M Campbell F Canelli A Canepa B Carls D Carlsmith R Carosi S Carrillo S Carron B Casal M Casarsa A Castro P Catastini D Cauz V Cavaliere M Cavalli-Sforza A Cerri L Cerrito Y C Chen M Chertok G Chiarelli G Chlachidze F Chlebana K Cho D Chokheli J P Chou W H Chung Y S Chung C I Ciobanu M A Ciocci A Clark G Compostella M E Convery J Conway M Corbo M Cordelli C A Cox D J Cox F Crescioli C Cuenca Almenar J Cuevas R Culbertson D Dagenhart N d'Ascenzo M Datta P de Barbaro S De Cecco G De Lorenzo M Dell'Orso C Deluca L Demortier J Deng M Deninno F Devoto M d'Errico A Di Canto B Di Ruzza J R Dittmann M D'Onofrio S Donati P Dong M Dorigo T Dorigo K Ebina A Elagin A Eppig R Erbacher D Errede S Errede N Ershaidat R Eusebi H C Fang S Farrington M Feindt J P Fernandez C Ferrazza R Field G Flanagan R Forrest M J Frank M Franklin J C Freeman Y Funakoshi I Furic M Gallinaro J Galyardt J E Garcia A F Garfinkel P Garosi H Gerberich E Gerchtein S Giagu V Giakoumopoulou P Giannetti K Gibson C M Ginsburg N Giokaris P Giromini M Giunta G Giurgiu V Glagolev D Glenzinski M Gold D Goldin N Goldschmidt A Golossanov G Gomez G Gomez-Ceballos M Goncharov O González I Gorelov A T Goshaw K Goulianos A Gresele S Grinstein C Grosso-Pilcher R C Group J Guimaraes da Costa Z Gunay-Unalan C Haber S R Hahn E Halkiadakis A Hamaguchi J Y Han F Happacher K Hara D Hare M Hare R F Harr K Hatakeyama C Hays M Heck J Heinrich M Herndon S Hewamanage D Hidas A Hocker W Hopkins D Horn S Hou R E Hughes M Hurwitz U Husemann N Hussain M Hussein J Huston G Introzzi M Iori A Ivanov E James D Jang B Jayatilaka E J Jeon M K Jha S Jindariani W Johnson M Jones K K Joo S Y Jun T R Junk T Kamon P E Karchin Y Kato W Ketchum J Keung V Khotilovich B Kilminster D H Kim H S Kim H W Kim J E Kim M J Kim S B Kim S H Kim Y K Kim N Kimura M Kirby S Klimenko K Kondo D J Kong J Konigsberg A V Kotwal M Kreps J Kroll D Krop N Krumnack M Kruse V Krutelyov T Kuhr M Kurata S Kwang A T Laasanen S Lami S Lammel M Lancaster R L Lander K Lannon A Lath G Latino I Lazzizzera T LeCompte E Lee H S Lee J S Lee S W Lee S Leo S Leone J D Lewis C-J Lin J Linacre M Lindgren E Lipeles A Lister D O Litvintsev C Liu Q Liu T Liu S Lockwitz N S Lockyer A Loginov D Lucchesi J Lueck P Lujan P Lukens G Lungu J Lys R Lysak R Madrak K Maeshima K Makhoul P Maksimovic S Malik G Manca A Manousakis-Katsikakis F Margaroli C Marino M Martínez R Martínez-Ballarín P Mastrandrea M Mathis M E Mattson P Mazzanti K S McFarland P McIntyre R McNulty A Mehta P Mehtala A Menzione C Mesropian T Miao D Mietlicki A Mitra H Miyake S Moed N Moggi M N Mondragon C S Moon R Moore M J Morello J Morlock P Movilla Fernandez A Mukherjee Th Muller P Murat M Mussini J Nachtman Y Nagai J Naganoma I Nakano A Napier J Nett C Neu M S Neubauer J Nielsen L Nodulman O Norniella E Nurse L Oakes S H Oh Y D Oh I Oksuzian T Okusawa R Orava L Ortolan S Pagan Griso C Pagliarone E Palencia V Papadimitriou A A Paramonov J Patrick G Pauletta M Paulini C Paus D E Pellett A Penzo T J Phillips G Piacentino E Pianori J Pilot K Pitts C Plager L Pondrom K Potamianos O Poukhov F Prokoshin A Pronko F Ptohos E Pueschel G Punzi J Pursley A Rahaman V Ramakrishnan N Ranjan I Redondo P Renton M Rescigno F Rimondi L Ristori A Robson T Rodrigo T Rodriguez E Rogers S Rolli R Roser M Rossi F Rubbo F Ruffini A Ruiz J Russ V Rusu A Safonov W K Sakumoto Y Sakurai L Santi L Sartori K Sato V Saveliev A Savoy-Navarro P Schlabach A Schmidt E E Schmidt M P Schmidt M Schmitt T Schwarz L Scodellaro A Scribano F Scuri A Sedov S Seidel Y Seiya A Semenov F Sforza A Sfyrla S Z Shalhout T Shears P F Shepard M Shimojima S Shiraishi M Shochet I Shreyber A Simonenko P Sinervo A Sissakian K Sliwa J R Smith F D Snider A Soha S Somalwar V Sorin P Squillacioti M Stancari M Stanitzki R St Denis B Stelzer O Stelzer-Chilton D Stentz J Strologas G L Strycker Y Sudo A Sukhanov I Suslov K Takemasa Y Takeuchi J Tang M Tecchio P K Teng J Thom J Thome G A Thompson E Thomson P Ttito-Guzmán S Tkaczyk D Toback S Tokar K Tollefson T Tomura D Tonelli S Torre D Torretta P Totaro M Trovato Y Tu F Ukegawa S Uozumi A Varganov F Vázquez G Velev C Vellidis M Vidal I Vila R Vilar J Vizán M Vogel G Volpi P Wagner R L Wagner T Wakisaka R Wallny S M Wang A Warburton D Waters M Weinberger W C Wester B Whitehouse D Whiteson A B Wicklund E Wicklund S Wilbur F Wick H H Williams J S Wilson P Wilson B L Winer P Wittich S Wolbers H Wolfe T Wright X Wu Z Wu K Yamamoto J Yamaoka T Yang

We report the most sensitive direct search for pair production of fourth-generation bottomlike chiral quarks (b') each decaying promptly to tW. We search for an excess of events with an electron or muon, at least five jets (one identified as due to a b or c quark), and an imbalance of transverse momentum by using data from pp collisions collected by the CDF II detector at Fermilab with an integ...

2006
R. J. Baxter

It has been known for some time that the Boltzmann weights of the chiral Potts model can be parametrized in terms of hyperelliptic functions, but as yet no such parametrization has been applied to the partition and correlation functions. Here we show that for N = 3 the function S(t p) that occurs in the recent calculation of the order parameters can be expressed quite simply in terms of such a ...

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