A New Preparation of 4-Aminobutyramide

Kleemann A, Leuchtenberger W, Martens J, Weigel H. A New Preparation of 4-Aminobutyramide. Angew. Chem. Int.Ed. Engl. 1980;19(8):627-627

Ein neuer Weg zu 4-Amino-buttersäureamid

Kleemann A, Leuchtenberger W, Martens J, Weigel H. Ein neuer Weg zu 4-Amino-buttersäureamid. Angew. Chem. 1980;92(8):640-640

A novel synthetic route to L-proline (Amino acids ; 7)

Reaction of L-5-oxoproline esters L-2 with phosgene at 0° C gives L-5,51-dichloro-1-(chlorocarbonyl)proliene esters L-6 ,which readily lose hydrogen chloride to form L-5-chloro-1-(chloroarbonyl)-4,5-dehydroproline esters L-7. Catalytic hydrogenation (Pd/C, 180 bar) of L-7 yields L-1-(chlorocarbonyl)proline esters L-15 and thence, upon hydrolysis, L-proline ( L17 ). A "one-pot reaction" for the whole sequence is described, starting from easily accessible L-5-oxoproline esters and yielding L-proline in 78% overall yield and 99.7% optical purity

Amino Acids

Drauz K, Grayson I, Kleemann A, Krimmer H-P, Leuchtenberger W, Weckbecker C. Amino Acids. In: Ullmann's encyclopedia of industrial chemistry. Vol 1. Weinheim: Wiley‐VCH Verlag GmbH & Co. KGaA; 2007

Unraveling Structure and Device Operation of Organic Permeable Base Transistors

Organic permeable base transistors (OPBTs) are of great interest for flexible electronic circuits, as they offer very large on-current density and a record-high transition frequency. They rely on a vertical device architecture with current transport through native pinholes in a central base electrode. This study investigates the impact of pinhole density and pinhole diameter on the DC device performance in OPBTs based on experimental data and TCAD simulation results. A pinhole density of NPin = 54 µm−2 and pinhole diameters around LPin = 15 nm are found in the devices. Simulations show that a variation of pinhole diameter and density around these numbers has only a minor impact on the DC device characteristics. A variation of the pinhole diameter and density by up to 100% lead to a deviation of less than 4% in threshold voltage, on/off current ratio, and sub-threshold slope. Hence, the fabrication of OPBTs with reliable device characteristics is possible regardless of statistical deviations in thin film formation. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei