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201.
New PNA analogues derived from aminoethylpyrrolidin-5-one backbone show stabilization of aepone-PNA:DNA hybrids and destabilization of the corresponding RNA hybrids compared to unmodified PNA. 相似文献
202.
A short and efficient RCM route is reported for the construction of the key nine-membered B ring of eleutherobin starting from the readily available 1,2,5,6-diisopropylidene-d-glucose. 相似文献
203.
Indoles react smoothly with sulfonyl chlorides in the presence of a catalytic amount of indium tribromide at ambient temperature to afford the corresponding 3-arylsulfonyl indole derivatives in high yields with high regioselectivity. 相似文献
204.
TsNBr2 reacts with alkyne in the presence of methanol to form α,α-dibromodimethyl ketals instantaneously. The reaction proceeds smoothly at room temperature without using any other catalyst. The one step reaction can be carried out with both aromatic and aliphatic alkynes in excellent yield. 相似文献
205.
Herein we report the synthetic strategy towards the pyran core of macrolactin 3 via Sharpless epoxidation, titanium(IV) mediated regioselective ring-opening reaction of epoxyallyl alcohol/epoxy alcohol and oxa-Michael addition as the key steps. 相似文献
206.
A fast, simple, and efficient protocol for the direct conversion of alcohols and aldehydes to methyl ester has been developed using TsNBr2 without any catalyst. The one pot reaction proceeds in the presence of a base at room temperature in methanol, to produce the corresponding methyl ester in high yield within a short time. 相似文献
207.
Haitao Wu Vincent Coble Olga Vasalatiy Rolf E. Swenson Murali C. Krishna James B. Mitchell 《Tetrahedron letters》2014
Nitroxides can ameliorate the toxic effects of radiation during cancer therapy. Nitroxides are paramagnetic and can be used in magnetic resonance imaging (MRI) and electron paramagnetic resonance imaging (EPRI) to monitor in vivo oxidative stress status. Compound 5 (3-(N-piperidinemethyl)-2,2,5,5-tetramethyl-1-oxy-3-pyrroline) was found to be the most effective nitroxide radioprotector. An efficient synthesis for this promising radioprotector was developed. 相似文献
208.
K. Raghavendra Rao Akula Raghunadh Ramamohan Mekala Suresh Babu Meruva T.V. Pratap T. Krishna Dipak Kalita Eppakayala Laxminarayana Bagineni Prasad Manojit Pal 《Tetrahedron letters》2014
A dual reactant/catalyst role of glyoxylic acid in the reaction of isatoic anhydride with various amines afforded a novel, robust and rapid synthesis of 3-(un)substituted quinazolin-4(3H)-ones. This metal catalyst-free reaction proceeds via an unusual and unexpected cleavage of C–C bond. A shorter and common route to two alkaloids, that is, rutaecarpine and evodiamine is also accomplished. 相似文献
209.
The first total synthesis of (Z,11S)-3,4-trans-11-hydroxy-3-methyldodec-cis-6-en-4-olide and (Z)-3,4-trans-11-oxo-3-methyldodec-cis-6-en-4-olide was accomplished using Jacobsen hydrolytic kinetic resolution, Ohira–Bestmann reaction, regioselective alkyne addition to terminal carbon atom of epoxide, intramolecular TEMPO/BAIB mediated oxidative lactonization and partial hydrogenation as the key steps. 相似文献
210.
Galla Raju Rajesh NomulaKallaganti V.S. Ramakrishna Palakodety Radha Krishna 《Tetrahedron letters》2014
The first total synthesis of (6Z,9S)-3,4-trans-9-hydroxy-3-methyldodec-cis-6-en-4-olide and (6Z)-3,4-trans-9-oxo-3-methyldodec-cis-6-en-4-olide was achieved in a convergent pathway. The salient features of our synthesis include Ohira–Bestmann reaction, regioselective alkyne addition to terminal epoxide, TEMPO/BAIB mediated oxidative lactonization, and partial hydrogenation. 相似文献