Microwave-assisted Claisen Rearrangement Research Articles

Selective C-7 Functionalization of Phenanthridines by Microwave-Assisted Claisen Rearrangements of 8-Allyloxyphenanthridines.

Carbon-carbon bond formation in the phenanthridine 7-position was achieved by microwave-assisted Claisen rearrangement of 8-allyloxyphenanthridines. The reactions took place with excellent regioselectivity and high chemical yields. If the 7-position was substituted, rearrangement to C-9 took place, but the reaction occurred less readily. Rearrangements of 8-allyloxy-5,6-dihydrophenanthridines (phenanthridines with a saturated B-ring) gave a mixture of 7- and 9-substituted products. The experimental results were supported by DFT (density functional theory) calculations.

Microwave-assisted Claisen Rearrangement of 1-Allyloxy-4-hydroxybenzene in the Presence of Metal Salt

Microwave-assisted Claisen rearrangement of allyloxybenzene with a hydroxyl group was conducted in the presence of metal salts. The rearrangement was promoted in the presence of an alkali metal salt, because the reaction substrate was converted into a phenoxide-type ion, which can efficiently absorb microwaves. In contrast, a Lewis acid was strongly coordinated to the ethereal oxygen, and this structure could also absorb microwaves efficiently.

Microwave-Assisted Claisen Rearrangement: Synthesis of Naturally Occurring TRAIL-Resistance-Overcoming Tyrosine Derivative

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a tumor necrosis factor (TNF) family ligand that binds on the death receptors, DR4 and DR5, activating apoptotic pathways selectively in cancer cells and thus has become a promising cancer therapeutic agent. Compound 1, isolated from Streptomyces sp. IFM 10937, has shown activity in overcoming TRAIL resistance in AGS cells. Synthesis of 1 has been accomplished from L-tyrosine in an overall high-yielding reaction sequence.

Microwave-assisted Claisen rearrangement of naphthyl 2-propynyl ethers: synthesis of naphthofurans

An efficient two-step approach for the synthesis of naphtho[1,2-b]furans and naphtho[2,1-b]furans has been developed. Various functionalized propargyl alcohols were etherified with α- or β-naphthol under Mitsunobu reaction conditions to give naphthyl 2-propynyl ethers, which underwent a facile microwave-assisted Claisen rearrangement and concomitant anionic cyclization to yield naphthofuran derivatives under basic reaction conditions.

Tipranavir analogous 3-sulfonylanilidotetronic acids: new synthesis and structure-dependent anti-HIV activity

Sulfonamide-containing tetronic acids 1, structural analogues of the HIV-1 protease inhibitor tipranavir, were synthesised in five steps including a microwave-assisted Claisen rearrangement of cinnamyl tetronates and a modified Charette cyclopropanation of the so-formed 3-allyltetronic acids. Compounds 1 with two non-H residues (R 1, R 2) at C-5 of the tetronate core exhibited structure-dependent antiviral activity in two HIV strains. Derivatives 1c (R 1=R 2=Me, R 3=Cl) and 1d (R 1,2=(CH 2) 5, R 3=Me) were most active (IC 50<10 μM) in the sensitive strain HIV NL4-3.

Microwave‐assisted claisen rearrangement. Application to the synthesis of angelicin derivatives

Abstractmagnified image4′‐(Hydroxy, chloro, amino, acetoxy and methoxy)‐methyl‐4,5′‐dimethylangelicins were efficiently and rapidly synthesized via Claisen rearrangement of 4‐methyl‐7‐[4‐(hydroxy, chloro, amino, acetoxy and methoxy)‐but‐2‐ynyloxy]‐coumarins respectively under microwave irradiation. Prominent among the advantages of this new method are operational simplicity, good yields in short reaction times and easy work‐up procedures employed.

Microwave‐Assisted Claisen Rearrangement on a Silica Gel Support.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Microwave-assisted Claisen rearrangement on a silica gel support

A fast, efficient and environmentally benign solvent-free procedure has been developed for microwave-assisted Claisen rearrangement on a silica gel support. Various bis-allyl ketones were prepared using this protocol.