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Titolo:
NMR spectroscopic investigations of mixed aggregates underlying highly enantioselective 1,2-additions of lithium cyclopropylacetylide to quinazolinones
Autore:
Parsons, RL; Fortunak, JM; Dorow, RL; Harris, GD; Kauffman, GS; Nugent, WA; Winemiller, MD; Briggs, TF; Xiang, BS; Collum, DB;
Indirizzi:
DuPont Pharmaceut, Chem Proc Res & Dev, Chamberworks, Deepwater, NJ 08023 USA DuPont Pharmaceut Deepwater NJ USA 08023 erworks, Deepwater, NJ 08023 USA Cornell Univ, Baker Lab, Dept Chem & Biol Chem, Ithaca, NY 14853 USA Cornell Univ Ithaca NY USA 14853 t Chem & Biol Chem, Ithaca, NY 14853 USA
Titolo Testata:
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
fascicolo: 37, volume: 123, anno: 2001,
pagine: 9135 - 9143
SICI:
0002-7863(20010919)123:37<9135:NSIOMA>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
REVERSE-TRANSCRIPTASE INHIBITOR; IMMUNODEFICIENCY-VIRUS TYPE-1; ORGANOLITHIUM COMPOUNDS; ASYMMETRIC-SYNTHESIS; N-BUTYLLITHIUM; 2,2,6,6-TETRAMETHYLPIPERIDIDE LITMP; HEXAMETHYLDISILAZIDE LIHMDS; NUCLEOPHILIC 1,2-ADDITION; ORGANOMETALLIC REAGENTS; ALKYLLITHIUM COMPOUNDS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
78
Recensione:
Indirizzi per estratti:
Indirizzo: Parsons, RL DuPont Pharmaceut, Chem Proc Res & Dev, Chamberworks, PRF-112,Deepwater, NJ 08023 USA DuPont Pharmaceut PRF-112 Deepwater NJ USA 08023 NJ 08023 USA
Citazione:
R.L. Parsons et al., "NMR spectroscopic investigations of mixed aggregates underlying highly enantioselective 1,2-additions of lithium cyclopropylacetylide to quinazolinones", J AM CHEM S, 123(37), 2001, pp. 9135-9143

Abstract

The solution structures of mixed aggregates derived from lithium alkoxidesand lithium acetylides were investigated as part of a program to develop practical syntheses of quinazolinone-based nonnucleoside reverse transcriptase inhibitors. Low-temperature Li-6, C-13, and N-15 NMR spectroscopies reveal that mixtures of lithium cyclopropylacetylide (RCCLi), a -(+)-carene-derived amino alkoxide (R*OLi), and lithium hexamethyldisilazide (LiHMDS) in THF/pentane afford a (RCCLi)(3)(R*OLi) mixed tetramer, a C-2-symmetric and asymmetric (RCCLi)(2)(R*OLi)(2) mixed tetramer, and a C-3-symmetric (RCCLi)(R*OLi)(3) mixed tetramer. Analogous mixtures of RCCLi/R*OLi in Et2O and Me2NEt also provide 3:1, 2:2, and 1:3 mixed tetramers. The stereochemistry of aggregation is highly sensitive to the medium. The C2-symmetric (RCCLi)2(R*OLi)2 mixed tetramer is formed in Et2O, whereas the asymmetric isomer is formed in Me2NEt. LiHMDS in THF is shown to be an efficient proton scavenger without forming LiHMDS-RCCLi or LiHMDS-R*OLi mixed aggregates. LiHMDS-RCCLimixtures form mixed aggregates in Me2NEt.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 12:05:14