Potential of covalently linked tamoxifen hybrids for cancer treatment: recent update.

Cancer is a complex disease and the second leading cause of death globally, and breast cancer is still a leading cause of cancer death in women. Tamoxifen is the most commonly used drug for breast cancer (ER-positive) treatment and chemoprevention, saving the lives of millions of patients every year. In addition, the tamoxifen template has been explored extensively for the development of selective estrogen receptor modulators (SERMs) applicable in breast cancer, osteoporosis, and postmenopausal symptom treatment.

Characterizing Covalently Sidewall-Functionalized SWCNTs by using H NMR Spectroscopy.

Unambiguous evidence for covalent sidewall functionalization of single-walled carbon nanotubes (SWCNTs) has been a difficult task, especially for nanomaterials in which slight differences in functionality structure produce significant changes in molecular characteristics. Nuclear magnetic resonance (NMR) spectroscopy provides clear information about the structural skeleton of molecules attached to SWCNTs. In order to establish the generality of proton NMR as an analytical technique for characterizing covalently functionalized SWCNTs, we have obtained and analyzed proton NMR data of SWCNT-substituted benzenes across a variety of para substituents.

Regiochemical Reversals in Nitrosobenzene Reactions with Carbonyl Compounds: α-Aminooxyketone versus α-Hydroxyaminoketone Products.

The Lewis acid-catalyzed reaction of nitrosobenzene with a ketone can produce an α-aminooxyketones or an α-hydroxyaminoketone, with reaction regiochemistry switching from the latter to the former, dependent upon the addition of Lewis acid or sterically-hindered solvent. While the latter (C-N bond formation) is easily explained by attack of the enolate α-carbon at N, the former (C-O bond formation) has been an enigma, with few proposed explanations, and none which explain simultaneously formation of both products and all the regiochemical reversals. Herein, the regiochemistry reversal is proposed to occur via (1) nucleophile formation governed by Hard and Soft Acids and Bases (HSAB) theory, (2) a nucleophilic attack by the enolate O at N, followed by (3) a [2,3]-sigmatropic rearrangement.

Characterization of a tamoxifen-tethered single-walled carbon nanotube conjugate by using NMR spectroscopy.

We report the synthesis and characterization of a tamoxifen-tethered single-walled carbon nanotube (SWCNT) conjugate, in which tamoxifen is covalently attached to the single-walled carbon nanotube via oxidation and esterification reactions for the first time. The functionalized SWCNT derivative was characterized by using spectroscopic techniques: IR, UV-vis, Raman, and (1)H NMR Spectroscopy. The attachment of the drug tamoxifen to SWCNTs is analogous to the gold conjugate, which provided an endocrine treatment for breast cancer.

Alkene selenenylation: A comprehensive analysis of relative reactivities, stereochemistry and asymmetric induction, and their comparisons with sulfenylation.

A broad perspective of various factors influencing alkene selenenylation has been developed by concurrent detailed analysis of key experimental and theoretical data, such as asymmetric induction, stereochemistry, relative reactivities, and comparison with that of alkene sulfenylation. Alkyl group branching α to the double bond was shown to have the greatest effect on alkene reactivity and the stereochemical outcome of corresponding addition reactions. This is in sharp contrast with other additions to alkenes, which depend more on the degree of substitution on C=C or upon substituent electronic effects.

Statistical Trends in Women's Participation in Science: Commentary on Valla and Ceci (2011).

Valla and Ceci (2011, this issue) describe the participation of women in science and claim that the increases in quantitative fields (e.g., mathematics, engineering, and physical sciences) are an exception to the statement that "Women's growth in the scientific workforce has been meteoric over the past 40 years" (p.

Effect of Single-Walled Carbon Nanotube Association upon H NMR Spectra of Representative Organonitrogen Compounds.

This report is important to achieving SWCNT solvation, understanding adsorption of molecules on SWCNT surfaces, and SWCNT characterization by NMR. Complexation of 1-methyl-2-pyrrolidone (NMP) and other selected organonitrogens with single-walled carbon nanotubes (SWCNTs) was studied by proton nuclear magnetic resonance (NMR). The magnitude of (1)H NMR chemical shift change upon SWCNT:organonitrogen complex formation represents the strength of the association.

Pristine single-walled carbon nanotube purity evaluation by using (1)H NMR spectroscopy.

Proper purity characterization of single-walled carbon nanotubes (SWCNTs) is an increasingly hot topic in the area of carbon nanotechnology. There are inconsistencies in purity characterization of SWCNT from manufacturers and in the literature. Purity of "as received," oven dried, and NaHCO(3)-washed SWCNTs of three commercially available brands (NanoLab, SWeNT, and HiPco) is explored by using a consistent methodology via proton nuclear magnetic resonance ((1)H NMR) spectroscopy comparison, across three NMR solvents: DMSO-d (6), CDCl(3), and D(2)O.

Using correlations to compare additions to alkenes: homogeneous hydrogenation by using Wilkinson's catalyst.

Plots of the logarithms of relative rates of homogeneous catalytic hydrogenation of alkenes (log k(rel) values) by using Wilkinson's catalyst versus their ionization potentials (IPs) and versus their lowest unoccupied molecular orbital energy levels (LUMOs) display good-to-excellent correlations. The correlations indicate that the rate-determining step of this reaction is a nucleophilic addition to the alkene double bond, which is dependent upon both electronic effects and steric effects. This conclusion is in agreement with only two of three previously proposed mechanisms for the reaction, effectively ruling out one in which the rate-determining step involves electrophilic addition to the alkene.