Short and sweet: Glycosidation of 2‐deoxyglycosyl imidates with I2 as shown in the scheme (Bn=benzyl, Bz=benzoyl, MS=molecular sieves) proceeds smoothly to provide the corresponding β‐linked 2‐deoxyglycosides in excellent yields and selectivity. This coupling method has been shown to be adaptable to the synthesis of various β‐linked oligosaccharides containing 2,6‐dideoxy‐ and 2,3,6‐trideoxyglycosides.
We developed metal-insulator-semiconductor-type organic light-emitting transistors (MIS-OLETs), and improved their properties by optimizing the device structure. MIS-OLETs showed a maximum drain current ofand on/off ratio of over 10 4 . Moreover an active-matrix display using MIS-OLETs on a plastic substrate was fabricated. The developed 16 Â 16 active-matrix-drive organic light-emitting transistors (AMOLET) showed excellent properties by optimizing device structure.
The authors report the characteristics of novel metal-insulator-semiconductor-type organic light-emitting transistors (MIS-OLETs). The drain current and luminescent intensity of the MIS-OLET can be controlled by changing hole injection carriers by applying a gate bias voltage. In addition, the high performance (400cd∕m2 at VD=−8V) of MIS-OLETs fabricated on a plastic substrate as well as on a glass substrate is demonstrated and described.
In this report, we describe the stereoselective synthesis of a combinatorial library comprised of 16 deoxyhexasaccharides that are related to a landomycin A sugar moiety, based on an orthogonal deprotection strategy. The use of an olivosyl donor containing a benzyl ether at the C3 position and benzoyl ester at the C4 position, and the olivosyl donor, a naphthylmethyl ether, and a p-nitrobenzylethyl or benzyl sulfonyl ester enabled the synthesis of a set of four diolivosyl units containing a hydroxyl group at the C3 or C4 position by a simple glycosylation and deprotection procedure. Using a phenylthio 2,3,6-trideoxyglycoside, alpha-selective glycosidation proceeded without anomerization of the 2,6-dideoxy-beta-glycosides. In addition, alkylhydroquinone and levulinoyl groups were found to be an effective set of orthogonal protecting groups for the anomeric position and a hydroxyl group. The coupling of all combinations of trisaccharide units in a beta-selective manner was accomplished by activation of the glycosyl imidate with I(2) and Et(3)SiH. No cleavage of the acid-labile 2,3,6-trideoxyglycoside was observed under the conditions used for the reactions. Finally, all of the protected hexasaccharides were deprotected by hydrolysis of the esters, microwave (MW) assisted cleavage of the 2-trimethylsilylethoxymethoxy (SEM) ether, and a Birch reduction.
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