Abstract 2‐Chlormethylpyridin (I) wird nach Substitution zu (II) mit Cyanmethyl‐benzolsulfonsäureester (III) in das Ammoniumsalz (IV) übergeführt, aus dem mit tert.‐Butylat das Aminonitril (V) erhalten wird.
Abstract Durch Bestrahlung von A‐Homocholestenon (I) entstehen die beiden Vinylverbindungen (IIa) und (IIb), in Aceton entstehen die Cyclopropane (IIIa) und (IIIb).
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganometallic methylation of nicotine and nicotine N-oxide. Reaction pathways and racemization mechanismsJeffrey I. Seeman, Henry V. Secor, Charles R. Howe, Charles G. Chavdarian, and Larry W. MorganCite this: J. Org. Chem. 1983, 48, 25, 4899–4904Publication Date (Print):December 1, 1983Publication History Published online1 May 2002Published inissue 1 December 1983https://pubs.acs.org/doi/10.1021/jo00173a023https://doi.org/10.1021/jo00173a023research-articleACS PublicationsRequest reuse permissionsArticle Views205Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
[ILLUSTRATION OMITTED] One goal of 21st-century education is to develop mature citizens who can identify issues, solve problems, and communicate solutions. What better way for students to learn these skills than by participating in a science and engineering fair? Fair participants face the same challenges as professional scientists and engineers, even Nobel laureates. By identifying intellectually stimulating problems, solving these problems, and communicating the results to others, students learn lessons that are valuable throughout their educational and working lives (Corsi 2010). But students who are tackling their first science fair projects inevitably have questions and anxieties. How do I choose my project? What do I do next? How do I interact with judges? The Archimedes Initiative (see On the web) is a free, online video archive named for the ancient Greek mathematician and scientist. (Other good online science fair resources include Science Buddies and the Intel International Science and Engineering Fair's [ISEF] website [see On the web]. The book Success With Science: The Winners' Guide to High School Research [Gaglani et al. 2011] [see References] is another good resource.) The videos in The Archimedes Initiative were recorded at county and state science fairs and ISEF. They show students addressing their peers (Figures 1A and 1B, p. 40). This article describes the content of The Archimedes Initiative, a free internet-based self-learning experience, and suggests how students, teachers, and parents can put it to good use. A self-directed learning experience The Archimedes Initiative can be useful to anyone engaged in a self-directed learning experience, particularly participants in traditional science fairs such as the ISEF or online fairs, such as the Google Science Fair, launched earlier this year (see On the web). There are three categories of videos: [FIGURE 1A OMITTED] [FIGURE 1B OMITTED] 17 theme videos Each four- to five-minute theme video (Figure 2) focuses on a single, practical subject. For example, in Choose Your Own Science Adventure, students explain how they chose their science fair projects. Figure 3 (p. 42) provides a full listing of these minidocumentaries, which show footage of several students speaking to the theme. At the end of each theme video, Dudley Herschbach, a 1986 Nobel Prize winner in chemistry and lifelong champion of science education and science appreciation among the general public, summarizes students' comments, relating their experiences to those of professional researchers and to life in general. Theme videos 1 through 9 track the typical sequence of conducting a research project, from forming a hypothesis to reaching a conclusion. In the other eight theme videos, students offer a range of tips and advice--from how to conquer fears to the advantages of working in a team. 49 project video series In these brief video clips, organized by project, individual students discuss their research projects, ranging in subjects from Alzheimer's disease to yeast fuel cells. Click on the Projects tab of the website and watch as many of the video clips about a selected project as you like. For example, click on Cockroaches to watch up to 14 videos in which a student scientist describes her project and discusses what she learned about herself, how she interacted with judges, and challenges she faced. These videos can inspire students to undertake their own projects and foster ideas for project subjects and methodologies. 19 topic video series In these short videos, found under the Topics tab, various students discuss the same topic, such as designing experiments or using mentors. The topics roughly parallel those listed in Figure 3. A student uncertain about selecting a project may want to watch some or all of the Choosing Your Experiment videos, in which students who have completed their projects reveal their motivations, experiences, and insights. …
In 1965, Woodward and Hoffmann proposed a theory to predict the stereochemistry of electrocyclic reactions, which, after expansion and generalization, became known as the Woodward–Hoffmann Rules. Subsequently, Longuet-Higgins and Abrahamson used correlation diagrams to propose that the stereoselectivity of electrocyclizations could be explained by the correlation of reactant and product orbitals with the same symmetry. Immediately thereafter, Hoffmann and Woodward applied correlation diagrams to explain the mechanism of cycloadditions. We describe these discoveries and their evolution. We now report an investigation of various electrocyclic reactions using DFT and CASSCF. We track the frontier molecular orbitals along the intrinsic reaction coordinate and modeled trajectories and examine the correlation between HOMO and LUMO for thermally forbidden systems. We also investigate the electrocyclizations of several highly polarized systems for which the Houk group had predicted that donor–acceptor substitution can induce zwitterionic character, thereby providing low-energy pathways for formally forbidden reactions. We conclude with perspectives on the field of pericyclic reactions, including a refinement as the meaning of Woodward and Hoffmann's "Violations. There are none!" Lastly, we comment on the burgeoning influence of computations on all fields of chemistry.
The Nozoe Autograph Books contain entries from, literally, around the world of organic chemistry. Many of the inscriptions showed the poetic or even musical side of their signees. This Essay presents a diverse selection of the poetic entries of the autograph books, starting with a musical puzzle. This Essay and the interactive website that accompanies the Nozoe Autograph Book project are available free-access for at least a three-year period at http://www.tcr.wiley-vch.de/nozoe.
Abstract On May 1, 1965, Roald Hoffmann and R. B. Woodward published their second joint communication, Selection Rules for Concerted Cycloaddition Reactions , in the Journal of the American Chemical Society . Herein is presented a historical analysis of Woodward and Hoffmann's determination of the mechanism of cycloadditions. This analysis is based on thorough analyses with Roald Hoffmann of his 1964 and 1965 laboratory notebooks and his archived documents and on numerous in‐person, video, and email interviews. This historical research pinpoints several seminal moments in chemistry and in the professional career of Hoffmann. For example, now documented is the fact that Woodward and Hoffmann had no anticipation that their collaboration would continue after the publication of their first 1965 communication on electrocyclizations. Also pinpointed is the moment in Hoffmann's professional and intellectual trajectories that he became a full‐fledged, equal collaborator with Woodward and Hoffmann's transition from a “calculator” to an “explainer.”
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