Synthesis of 2-D-L-tryptophan by sequential Ir-catalyzed reactions

Herein, we report a practical synthesis of 2-D-l-tryptophan via sequential Ir-catalyzed CH borylation, and Ir-catalyzed C-2-deborylative deuteration steps. In this synthetic sequence, deprotection of the Boc and methyl ester groups proved challenging, due to replacement of deuterium with hydrogen. However, mild deprotection conditions were developed to avoid this D/H scrambling. Further, 2-D-L-Tryptophan is stable in many buffers used for biological studies.     

Rational design of methacrylate monomers containing oxadiazole moieties for single‐layer organic light emitting devices

Methacrylate derived monomers functionalized with pendant oxadiazole moieties were synthesized and copolymerized with carbazole containing monomers to form polymers with electron and hole transporting fragments in the same molecule. Substituents on the oxidazole moiety were varied with the purpose of bandgap tuning and performance optimization when employed in single‐layer organic light emitting devices (OLED). Quantum mechanical calculations of the HOMO‐LUMO levels of the oxidazole derivatives were used to down‐select promising candidates for chemical synthesis and testing in single‐layer OLEDs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1663–1673     

Cycloaddition Reactions of an Active Cyclic Phosphane/Borane Pair with Alkenes,Alkynes, and Carbon Dioxide

The active six-membered cyclo-FLP 6 undergoes a rapid P/B addition reaction to carbon dioxide. At elevated temperature, the resulting heterobicyclo[2.2.2]octane derived product 7 undergoes ring opening and equilibrates with the cyclotetramer (7)₄ . In the large macrocyclic structure, four monomeric six-membered cyclo-FLP units are connected by four CO₂ molecules to form the supramolecular ring system. The P/B cyclo-FLP 6 undergoes a variety of additional cycloaddition reactions.     

Copper‐Catalyzed Amidation of Primary and Secondary Alkyl Boronic Esters

The oxidative copper‐catalyzed cross‐coupling of functionalized alkyl boronic esters with primary amides is reported. Through the identification of appropriate diketimine ligands, conditions for efficient coupling of both primary and secondary alkyl boronic esters with diverse primary amides, including acetamide, have been developed.     

Generators and normal forms of Richard Thompson’s group F and the four-color theorem

We use a result of Kauffman to explore the connection between Richard Thompson’s Group F and the four-color theorem.     

Small Scale Models Subjected to Buried Blast Loading Part I: Floorboard Accelerations and Related Passenger Injury Metrics with Protective Hulls

Small scale models representing key vehicle structural elements, including both floorboards and bottom-mounted, downward V-shape hulls in various configurations, have been manufactured and subjected to a range of buried blast loading conditions. By varying surface stand-off distance and depth of burial for several hull and structure configurations, the input-scaled response of aluminum full-scale vehicle floorboards has been quantified using high speed stereo-vision. Specifically, the maximum vertical acceleration on the floorboard and the corresponding Head Injury Criterion (HIC₁₅) are quantified as metrics to assess the severity of the blast event. Results show standard V-shaped hulls provide essential blast mitigation, with reductions in floorboard measurements up to 47X in maximum acceleration and HIC₁₅. Though variations in protective hull geometry provide modest reductions in the severity of a floorboard blast event, results also show that personnel on typical floorboard structures during blast loading events will incur unacceptable shock loading conditions, resulting in either serious or fatal injury. A more appropriate design scenario would be to consider situations that employ frame-mounted passenger seating to reduce the potential for injury. A second set of experiments will be presented in Part II that focuses on frame motions and accelerations when steel frames and steel structures are employed with various frame connections and coatings for frame blast mitigation.