Abstract:
:We have examined the use of our bis(sulfonamide) diol ligand (1) in the asymmetric addition of phenyl groups to cyclic alpha,beta-unsaturated ketones. Good to excellent enantioselectivities have been obtained with cyclic enones bearing alkyl substituents in the 2 position (71-97% enantiomeric excess). Furthermore, excellent enantioselectivities have been observed in the asymmetric phenylation of cyclic enones with 2-iodo and 2-bromo substituents. The results of this study broaden the scope of the asymmetric additions to ketones promoted by the titanium catalyst derived from ligand 1.
journal_name
Proc Natl Acad Sci U S Aauthors
Li H,García C,Walsh PJdoi
10.1073/pnas.0307119101keywords:
subject
Has Abstractpub_date
2004-04-13 00:00:00pages
5425-7issue
15eissn
0027-8424issn
1091-6490pii
0307119101journal_volume
101pub_type
杂志文章abstract::Treatment of a human breast cancer cell line (MDA-MB-435) in nude mice with a recombinant adenovirus containing the human interferon (IFN) consensus gene, IFN-con1 (ad5/IFN), resulted in tumor regression in 100% of the animals. Tumor regression occurred when virus was injected either within 24 hr of tumor cell implant...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.9.4513
更新日期:1996-04-30 00:00:00
abstract::Our anatomical analysis revealed that a dry maize seed contains four to five embryonic leaves at different developmental stages. Rudimentary kranz structure (KS) is apparent in the first leaf with a substantial density, but its density decreases toward younger leaves. Upon imbibition, leaf expansion occurs rapidly wit...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1301009110
更新日期:2013-03-05 00:00:00
abstract::cDNA array technology has proven to be a powerful way to monitor global changes in gene expression patterns. Here, we present an approach that extends the current utility of cDNA arrays to allow the evaluation of the relative roles of transcription and mRNA turnover in governing gene expression on a global basis, comp...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.162212399
更新日期:2002-08-06 00:00:00
abstract::The testis-determining gene Sry is located on the short arm of the mouse Y chromosome in a region known to have undergone duplications and rearrangements in comparison with the equivalent portion of the human Y chromosome. Detailed analysis of the Sry genomic locus reveals a further difference in that the mouse Sry op...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.17.7953
更新日期:1992-09-01 00:00:00
abstract::Surface topography profoundly influences cell adhesion, differentiation, and stem cell fate control. Numerous studies using a variety of materials demonstrate that nanoscale topographies change the intracellular organization of actin cytoskeleton and therefore a broad range of cellular dynamics in live cells. However,...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1910166116
更新日期:2019-11-12 00:00:00
abstract::The protease encoded by the human immunodeficiency virus (HIV) processes the viral gag and gag-pol protein precursor by posttranslational cleavage. In this study we have demonstrated by site-specific mutagenesis (Asp----Thr) and by pepstatin A inhibition that the recombinant HIV protease is an aspartic-type protease. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.18.6612
更新日期:1988-09-01 00:00:00
abstract::We propose a model for DNA polymerase fidelity in which free energy differences, delta delta G, between matched and mismatched nucleotides are magnified at the enzyme's active site. Both hydrogen bonding and stacking components of the interaction energy are amplified, with the most profound effect being on the magnitu...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.6.1559
更新日期:1986-03-01 00:00:00
abstract::By indirect immunofluorescence techniques, microtubules and mitochondria were localized in normal rat kidney cells, human WI38 fibroblasts, mouse peritoneal macrophages, and a putative smooth muscle rat cell line, in monolayer culture. The mitochondria were found to be arranged along the cytoplasmic microtubules in ea...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.75.8.3863
更新日期:1978-08-01 00:00:00
abstract::We have reexamined the balance between cell birth, cell maturation, and cell death in the thymus by labeling dividing thymocytes and their progeny in vivo with [3H]-thymidine, isolating clearly defined subpopulations by fluorescence-activated cell sorting, and determining the distribution of label by autoradiography. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.7.2579
更新日期:1990-04-01 00:00:00
abstract::The phosphorylation of protein I, a specific neuronal protein, has been found to be regulated both by cyclic AMP (cAMP) and by calcium, in intact as well as in lysed synaptosome preparations from rat brain. In order to determine the phosphorylation site(s) of protein I that were regulated by cAMP and calcium, protein ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.76.10.5402
更新日期:1979-10-01 00:00:00
abstract::The bacterial superantigen staphylococcal enterotoxin A (SEA) is an extremely potent activator of T lymphocytes when presented on major histocompatibility complex (MHC) class II molecules. To develop a tumor-specific superantigen for cancer therapy, we have made a recombinant fusion protein of SEA and the Fab region o...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.19.8945
更新日期:1994-09-13 00:00:00
abstract::The mouse sperm receptor, a glycoprotein called ZP3, is synthesized and secreted by growing oocytes. It is present in more than a billion copies in the unfertilized egg's extracellular coat, or zona pellucida. We have cloned and characterized a region of the mouse (CD-1) genome that spans 10 kilobases of the ZP3 locus...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.17.6409
更新日期:1988-09-01 00:00:00
abstract::The spread of bacteria resistant to antimicrobial agents calls for population-wide treatment strategies to delay or reverse the trend toward antibiotic resistance. Here we propose new criteria for the evaluation of the population-wide effects of treatment protocols for directly transmitted bacterial infections and dis...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.22.12106
更新日期:1997-10-28 00:00:00
abstract::An homologous in vitro assay for yeast nonsense suppressors was used to examine the effect of the cytoplasmically inherited genetic determinant [psi] on the efficiency of in vitro nonsense suppression. The efficiency of all three types of yeast tRNA-mediated nonsense suppressor (ochre, amber, and UGA) is much greater ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.80.10.2824
更新日期:1983-05-01 00:00:00
abstract::Clones of embryonic chick chondrocytes have been isolated and collagen biosynthesis has been followed as the clones grow and eventually lose division capacity. Analysis of collagen type at each successive subculture until the time of cellular senescence has shown that a change in synthesis occurs from the cartilage-sp...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.5.1674
更新日期:1976-05-01 00:00:00
abstract::Animals capable of regenerating multiple tissue types, organs, and appendages after injury are common yet sporadic and include some sponge, hydra, planarian, and salamander (i.e., newt and axolotl) species, but notably such regenerative capacity is rare in mammals. The adult MRL mouse strain is a rare exception to the...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1000830107
更新日期:2010-03-30 00:00:00
abstract::By comparing the amino acid sequences of 11 mammalian and 1 avian prion proteins (PrP), structural analyses predicted four alpha-helical regions. Peptides corresponding to these regions of Syrian hamster PrP were synthesized, and, contrary to predictions, three of the four spontaneously formed amyloids as shown by ele...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.89.22.10940
更新日期:1992-11-15 00:00:00
abstract::Among the earliest and most important stages during tumorigenesis is the activation of the angiogenic process, an event that is termed the "switch to the angiogenic phenotype." We have developed an in vivo system that can reliably recapitulate the stages in tumor development that represent this transition. Using this ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.97.8.3884
更新日期:2000-04-11 00:00:00
abstract::We have previously proven that human macrophages can phagocytose porcine cells even in the absence of Ab or complement opsonization, indicating that macrophages present a pivotal immunological obstacle to xenotransplantation. A recent report indicates that the signal regulatory protein (SIRP)alpha is a critical immune...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0609661104
更新日期:2007-03-20 00:00:00
abstract::The energy landscape theory provides a general framework for describing protein folding reactions. Because a large number of studies, however, have focused on two-state proteins with single well-defined folding pathways and without detectable intermediates, the extent to which free energy landscapes are shaped up by t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0804774105
更新日期:2008-12-09 00:00:00
abstract::When two phases of water are at equilibrium, the ratio of hydrogen isotopes in each is slightly altered because of their different phase affinities. This isotopic fractionation process can be utilized to analyze water's movement in the world's climate. Here we show that equilibrium fractionation ratios, an entirely qu...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1203365109
更新日期:2012-05-22 00:00:00
abstract::Cyclic AMP concentrations were low for an adenylate cyclase-deficient mutant (cya(-)) and abnormally high for a catabolite receptor protein-deficient mutant (crp(-)). A fall in cellular cAMP concentration was always found when cells were subjected to transient repression. No consistent correlations were observed betwe...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.4.1436
更新日期:1974-04-01 00:00:00
abstract::Elevated eukaryotic initiation factor 4E (eIF4E) levels frequently occur in a variety of human cancers. Overexpression of eIF4E promotes cellular transformation by selectively increasing the translation of proliferative and prosurvival mRNAs. These mRNAs possess highly structured 5'-UTRs that impede ribosome recruitme...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1303781110
更新日期:2013-08-13 00:00:00
abstract::Approximately 15 per cent of the light chains from homogeneous immunoglobulins in patients with multiple myeloma contain an oligosaccharide group. Five human myeloma light chains that contained carbohydrate were studied. The sequence Asn-[unk]-Ser/Thr was at the site of carbohydrate attachment in all light chains. The...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.66.3.975
更新日期:1970-07-01 00:00:00
abstract::We report on label-free imaging, detection, and mass/size measurement of single viral particles in solution by high-resolution surface plasmon resonance microscopy. Diffraction of propagating plasmon waves along a metal surface by the viral particles creates images of the individual particles, which allow us to detect...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1005264107
更新日期:2010-09-14 00:00:00
abstract::To improve the efficacy of plasminogen activators, we produced a monoclonal antibody (RWR) that inhibits human alpha 2-antiplasmin (alpha 2AP). In addition to inhibiting alpha 2AP in plasma, RWR binds to and inhibits fibrin cross-linked alpha 2AP and reproduces the "spontaneous" clot lysis that is the hallmark of huma...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.3.1114
更新日期:1990-02-01 00:00:00
abstract::Innate immunity can facilitate nervous system regeneration, yet the underlying cellular and molecular mechanisms are not well understood. Here we show that intraocular injection of lipopolysaccharide (LPS), a bacterial cell wall component, or the fungal cell wall extract zymosan both lead to rapid and comparable intra...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1423221112
更新日期:2015-02-24 00:00:00
abstract::Cytochrome P450IIC5 (rabbit liver 21-hydroxylase) is unusual among hepatic forms of cytochromes P450 because it catalyzes the conversion of one active steroid hormone (progesterone) to another active hormone (deoxycorticosterone). Another interesting aspect of this steroid-hydroxylating enzyme is the ability to conver...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.24.9756
更新日期:1990-12-01 00:00:00
abstract::To improve the usefulness of in vivo mode for the investigation of the pathophysiology of human immunodeficiency virus (HIV) infection, we modified the construction of SCID mice implanted with human fetal thymus and liver (thy/liv-SCID-hu mice) so that the peripheral blood of the mice contained significant numbers of ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.7.3126
更新日期:1996-04-02 00:00:00
abstract::Programmed cell death regulates a number of biological phenomena, and the apoptotic signal must itself be tightly controlled to avoid inappropriate cell death. We established a genetic screen to search for molecules that inhibit the apoptotic signal from the Fas receptor. Here we report the isolation of a gene, LFG, t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.22.12667
更新日期:1999-10-26 00:00:00