Tetrabromo hydrogenated cardanol: Efficient and renewable brominating agent

2,4,4,6-Tetrabromo-3-n-pentadecyl-2,5-cyclohexadienone (TBPCO) has been synthesized and used as a new efficient, convenient, and environmentally friendly brominating agent.     

Intramolecular ene reaction of 1,6-fullerenynes: a new synthesis of allenes

[Structure: see text] Thermal treatment of 1,6-fullerenynes bearing an alkyl group on the terminal carbon of the alkyne moiety leads quantitatively to new allenes through a reaction mechanism involving an intramolecular ene process. This reaction outcome is in contrast to that recently found for free terminal alkynes which form cyclobutene derivatives through a [2+2] cyclization mechanism.     

Determination of the axial-vector weak coupling constant with ultracold neutrons

A precise measurement of the neutron decay β asymmetry A? has been carried out using polarized ultracold neutrons from the pulsed spallation ultracold neutron source at the Los Alamos Neutron Science Center. Combining data obtained in 2008 and 2009, we report A? = -0.119?66±0.000?89{-0.001?40}{+0.001?23}, from which we determine the ratio of the axial-vector to vector weak coupling of the nucleon g{A}/g{V}=-1.275?90{-0.004?45}{+0.004?09}.     

Reversible microwave-assisted cycloaddition of aziridines to carbon nanotubes

We report a new approach that uses microwaves to rapidly functionalize carbon nanotubes by using 1,3-dipolar cycloaddition of aziridines, well-known precursors to azomethine ylides, in solvent-free conditions. The efficiency of our microwave-mediated protocol is confirmed by comparison to a similar protocol in classical conditions for the azomethine ylides in DMF. Under these latter conditions, the reaction proceeds in 5 days (against 1 h under microwave irradiation), and the functionalization degree is much lower, as confirmed by thermogravimetric analysis and Raman spectroscopy. With our procedure, we easily scale-up the reaction up to 250 mg of functionalized MWNT in 1 h. We also provide an indirect proof of the covalent sidewall functionalization of the tubes.     

Azavinyl azomethine ylides from thermal ring opening of alpha-aziridinohydrazones: unprecedented 1,5-electrocyclization to imidazoles

Michael-type addition of aziridinecarboxylates to 1,2-diaza-1,3-butadienes under solvent-free conditions (SFC) resulted in the formation of alpha-aziridinohydrazone adducts. In toluene under reflux, alpha-aziridinohydrazones gave imidazoles in moderate to good yields. Such a reactivity pattern is explained by 1,5-electrocyclization of azavinyl azomethine ylide generated through thermal ring opening of alpha-aziridinohydrazones.     

A New Convenient Liquid‐ and Solid‐Phase Synthesis of Quinoxalines from (E)‐3‐Diazenylbut‐2‐enes

3‐{[(tert‐Butoxy)carbonyl]diazenyl}but‐2‐enoates react in tetrahydrofuran at room temperature with aromatic 1,2‐diamines to give 3‐methylquinoxaline‐2‐carboxylates. These products were also obtained in solid‐phase synthesis, by using polymer‐bound 3‐diazenylbut‐2‐enes.     

Simple Direct Synthesis of New 1-Heterocyclamino-3-Carbonylaminopyrroles by Reaction of Heterocyclic Azoalkenes with β-Ketoamides

Pyrrole and several its derivatives have been subjected to extensive chemical investigations, while substituted 1-aminopyrroles remain a class of compounds about which relatively little is known due to the far from trivial problem sposed by their syntheis. In fact, 1-aminopyrroles appear to be prepared mainly by direct reactionfrom conjugated azoalkenes,2 that unfortunately represent a class of relatively little