Richard B. Turner

Heats of hydrogenation : Acepleiadylene

Abstract The heat of hydrogenation of acepleiadylene (1) to the corresponding decahydro derivative 5 is −88·35 ± 0·45 kcal/mole, whereas the heat of hydrogenation of acepleiadane to 5 is −29·75 ± 0·13 kcal/mole. If the heats of hydrogenation of cyclopentene (−25·7 kcal/mole) and cycloheptene (−25·9 kcal/mole) are used as models to calculate the heat of hydrogenation of the three non-naphthalene double bonds, the value for these three double bonds in such a hypothetical, non-resonating model would be −77·5 kcal/mole in contrast to the experimentally found value of −58·6 kcal/mole. This indicates that the “conjugation” energy of the three non-naphthalene double bonds in acepleiadylene is approximately 18·9 kcal/mole.

An interesting synthesis of 3-methoxy-2,6-dimethylphenethyl alcohol

Abstract A simple procedure for the conversion of m-methoxyphenethyl alcohol into 3-methoxy-2,6-dimethylphenethyl alcohol by internal methylation is described.

The thermochemical evidence for hyperconjugation

Abstract Thermochemical evidence pertinent to the question of hyperconjugation is reviewed with the following conclusions. The data indicate that alkyl substitution at an unsaturated linkage results in stabilization of appreciable magnitude which is essentially independent of the nature of the alkyl group and which cannot, in the general case, be accounted for in terms of steric effects. Beyond these facts the calorimetric results do not provide significant information on the nature of the stabilization process and hence cannot distinguish among various interpretations that have been advanced in explanation of this phenomenon.

Stroke—call for papers

In the USA, someone has a stroke every 40 seconds or so, and stroke is a leading cause of death in most countries. Although improved management has reduced mortality in developed countries, disability and health-care costs remain substantial. Expansion of the obesity map to include developing countries, and an elevated risk of stroke in South Asian men, for example, mean that the need for prevention and treatment of stroke can only increase. To coincide with the 20th European Stroke Con ference in Hamburg, Germany, on May 24–27, 2010, The Lancet and The Lancet Neurology invite submissions of highquality research on the diagnosis, treatment, or prevention of ischaemic and haemorrhagic stroke. Randomised trials are especially welcome, but we also encourage submission of other studies with the potential to change practice. All articles should be submitted via the journals’ online submission systems, with a covering note stating that the submission is in response to this call, and specifying whether the article should be considered by one or both journals. We look forward to reading your work, which must be submitted by Feb 21, 2011. Please let us know about studies to be presented at the conference, so that simultaneous electronic publication can be planned.

Call for papers—oncology and haematology

The Lancet and The Lancet Oncology are announcing plans for issues of each journal to be devoted to specifi c topics in oncology and also to haematology. The former will be timed to coincide with the European Society of Medical Oncology (ESMO) congress in Milan, Italy (Oct 8–12, 2010), and the latter with the American Society of Hematology (ASH) annual meeting in Orlando, FL, USA (Dec 4–7, 2010). We would like to invite submissions of high-quality original research about cancers of the breast, lung, prostate, and gastrointestinal tract, or on any topic in haematology or haematological oncology. We are especially interested in reports of randomised clinical trials, but welcome other studies that have the potential to change clinical practice. Accepted papers will be published in either The Lancet or The Lancet Oncology via fast-track peer review to coincide with either the ESMO or ASH annual meetings, as appropriate. Submissions to coincide with the ESMO annual meeting must be received by June 25, 2010, and those for the ASH annual meeting by Oct 1, 2010, via either The Lancet or The Lancet Oncology’s online submission systems. Please state in your covering letter that the submission is in response to this call for papers. If your work is being presented at either meeting and falls under an embargo policy, please tell us the date and time of the presentation, and whether the study is to be presented orally or in a poster. If your paper is accepted, online publication can be scheduled to coincide with the presentation and comply with any press embargo.

Pyrazoline stereochemistry: use of nuclear magnetic resonance shift reagents with azo-compounds

Eu(fod)3 shifts the n.m.r. spectra of cis-azo-compounds, shereas trans-azo-compounds remain almost unaffected; shifts obtained from pyrazolines have been related to their stereochemistry.

Stereochemical studies. Part XLVII. Conformational analysis of many-membered ring compounds. The cyclododecenes

The equilibrium has been determined for an eight-component system of position- and cis–trans-isomeric 1,1,4,4-tetramethylcyclododecenes; enthalpies of hydrogenation have been measured for the cis- and trans-1,1,4,4-tetramethylcyclododec-8-ene pair; large differences in the relative stabilities and hydrogenation enthalpies have been found. The results are discussed in conformational terms and possible conformations of the cis- and trans-cyclododecenes are considered.