The first active aza analogue of narciclasine was synthesized from a pentasubstituted derivative of nicotinic acid. The key features of the synthesis include a halogen dance of bromopyridine and an intramolecular Heck reaction with a conduramine derived chemoenzymatically from bromobenzene. 10‐Aza‐narciclasine was found to have reasonable activity against several cancer cell lines.
A one‐pot, three‐component method for preparation of 1,4,5‐trisubstituted 5‐acyl‐1,2,3‐triazoles has been developed based on a highly selective acylation of the copper(I)‐carbon(sp2) bond with acyl chlorides in the presence of the copper(I)‐carbon(sp) bond. The procedure is characterized by high efficiency and simple conditions.
We report here that the silver triflate‐catalyzed cyclization of 2‐amino‐6‐propargylamineazines affords new and highly functionalized iminoimidazoazines. We have investigated the scope and limitations of the present methodology, and some aspects of the reactivity of the resulting iminoimidazopyridines have been explored, and a DFT‐based mechanistic analysis of the silver triflate‐catalyzed cyclization has been undertaken.
α‐Substituted β‐acetyl amides could undergo C C bond cleavage to form α‐keto amides when treated with copper(II) chloride (CuCl2) and boron trifluoride diethyl etherate (BF3⋅OEt2) under an oxygen atmosphere. The yield can be increased by the addition of tert‐butyl hydroperoxide which alone can also effect the reaction. The reaction provides a new protocol for the synthesis of α‐keto amides.
A new multipurpose glycine equivalent for the general asymmetric synthesis of α‐amino acids is introduced. The chiral reagent can be transformed to various amino acids by alkylations with alkyl halides as well as aldol and Michael addition reactions under operationally convenient reaction conditions at room temperature with virtually complete stereochemical control.
An aluminium(III) chloride‐catalyzed three‐component reaction of aromatic aldehydes, nitroalkanes, and sodium azide has been developed; this reaction sequence can be applied to a broad substrate scope and affords the corresponding 4‐aryl‐NH‐1,2,3‐triazoles in good to excellent yields. The milder reaction conditions and easier operation make this AlCl3‐catalyzed protocol more advantageous for the synthesis of 4‐aryl‐NH‐1,2,3‐triazoles.
In the presence of sodium carbonate, the [4+3] cycloadditions of α‐halogeno hydrazones with nitrones were performed efficiently, and affording 2,3,4,7‐tetrahydro‐1,2,4,5‐oxatriazepines in moderate to high yields.
The iron(III) chloride‐multicatalyzed dioxygenation of enamides with TEMPO in the presence of alcohols has been developed. This multicomponent domino process affords efficient new strategies for the synthesis of α‐oxy‐N‐acylhemiaminals or α‐oxyimides in good to excellent yields under mild conditions.
