Pharmacokinetics of Py-Im polyamides depend on architecture: cyclic versus linear

The pharmacokinetic properties of three pyrrole-imidazole (Py-Im) polyamides of similar size and Py-Im content but different shape were studied in the mouse. Remarkably, hairpin and cyclic oligomers programmed for the same DNA sequence 5'-WGGWWW-3' displayed distinct pharmacokinetic properties. Furthermore, the hairpin 1 and cycle 2 exhibited vastly different animal toxicities. These data provide a foundation for design of DNA binding Py-Im polyamides to be tested in vivo.     

Microwave assisted synthesis of bridgehead alkenes

A new, concise method to synthesize triene precursors for the type 2 intramolecular Diels-Alder reaction has been developed. Microwave irradiation of the trienes provides a convenient method for the synthesis of bridgehead alkenes. Higher yields, shorter reaction times, and lower reaction temperatures provide a general and efficient route to this interesting class of molecules.     

Microwave assisted stereospecific synthesis of d-erythro-l-gluco-nonulose

A convenient, highly efficient synthesis of d-erythro-l-gluco-nonulose from a new 2-C-(hydroxymethyl) branched-chain aldose is presented. The nucleophilic addition of the appropriately protected aldose to formaldehyde afforded 2-C-(hydroxymethyl)-d-erythro-l-manno-octose. The branched sugar bearing a CH₂OH group at C-2 provides access to a nine-carbon sugar in a single step through a stereospecific isomerization. The isomerization exploited the catalytic effect of molybdate ions and microwave irradiation. The structure of the product was analyzed by NMR spectra and quantum-chemical DFT calculations. DFT-computed proton–proton coupling constants were found to be comparable with the experimentally obtained coupling constants and agreed with the pyranose form of this branched-chain aldose.     

Microwave assisted synthesis of enantiomerically pure allylboronates

Stable allylboronates with a stereogenic centre α to the boronic ester moiety represent versatile reagents for stereoselective synthesis of homoallylic alcohols. Use of microwave irradiation in desilylation and sigmatropic rearrangement reactions allows rapid synthesis of α-chiral allylboronates utilized in the highly diastereo- and enantioselective synthesis of (Z)-configured homoallylic α-hydroxy esters by allyl additions to ethyl glyoxylate.     

Microwave assisted synthesis of novel annealed porphyrins

New pyrrole derivatives (isoindoles) have been readily prepared by the reaction of an α,β-unsaturated sulfone with ethyl isocyanoacetate in the presence of tert-BuOK in good yields. The isoindoles are converted into new porphyrins which undergo retro Diels-Alder reactions under microwave irradiation at 250 °C for 4 min to give novel annealed porphyrins in quantitative yields.     

Microwave assisted synthesis of spiro-2,5-diketopiperazines

A general and efficient method for the synthesis of spiro-2,5-diketopiperazines (spiro-DKPs) is described. Cyclization of Boc-protected dipeptides containing spiro-amino acids by microwave assisted heating in water furnished the corresponding spiro-DKPs. The spiro-amino acids were prepared by combining stereoselective alkylation reactions using the Schöllkopf methodology for amino acid construction with Grubbs ring-closing metathesis (RCM) methodology using ruthenium complexes. The RCM reactions and all subsequent transformations to the spiro-DKPs were run with microwave assisted heating, resulting in high yields and short reaction times for all steps.     

Microwave assisted synthesis of an unusual dinitro phytochemical

A novel dinitro secondary metabolite, 2-nitro-4-(2^′-nitroethenyl)phenol from a marine source, has been prepared via highly accelerated, microwave assisted, nitration reactions using mild reagents. ipso-Substitution of a carboxy group by a nitro group is discussed.     

Microwave assisted synthesis of triazolobenzoxazepine and triazolobenzoxazocine heterocycles

Intramolecular click chemistry was utilized to effect synthesis of the benzofused, triazole ring systems. The trimethylsilyl group was found to impede the reaction progress, and therefore, conditions employing in situ removal of the TMS group coupled with microwave irradiation give the penultimate targets with good conversion.     

Microwave assisted solvent free synthesis of 1,3-diphenylpropenones

Background  

1,3-Diphenylpropenones (chalcones) are well known for their diverse array of bioactivities. Hydroxyl group substituted chalcones are the main precursor in the synthesis of flavonoids. Till date various methods have been developed for the synthesis of these very interesting molecules. Continuing our efforts for the development of simple, eco-friendly and cost-effective methodologies, we report here a solvent free condensation of aryl ketones and aldehydes using iodine impregnated alumina under microwave activation. This new protocol has been applied to a variety of substituted aryl carbonyls with excellent yield of substituted 1,3-diphenylpropenones.     

Microwave assisted synthesis of 10b-aza-10c-borapyrene

The synthesis of 10b-aza-10c-borapyrene, an analog of the polycyclic aromatic hydrocarbon pyrene with an internal boron–nitrogen bond, has been improved. We have dramatically reduced the reaction times and ease of workup for the synthesis of this molecule by using a microwave reactor and carefully controlling reaction conditions.     

Microwave assisted synthesis of ring junction heterocyclic antioxidants

A series of 6,7-dihydro-[1,2,4]triazolo[5,1-b]quinazolin-8(5H)-ones, 4a–o were synthesized via a one-pot, multicomponent reaction in the presence of water as a solvent under microwave irradiation using ceric ammonium nitrate as an oxidizing agent. This techno-chemical method provides a rapid construction of higher molecules in short duration with high yield. The adopted method was carried out in the presence of water without catalyst and yielded the compounds without any side products, and thus further purification of compounds by column chromatography was not required. All the synthesized compounds, 4a–o were screened for their 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. All the compounds, 4a–o possessed moderate antioxidant activity when compared to their standard antioxidant (ascorbic acid).     

Microwave assisted synthesis of N-arylheterocyclic substituted-4-aminoquinazoline derivatives

A simple, efficient, and general method has been developed for the synthesis of various N-aryl heterocylic substituted-4-aminoquinazoline compounds from 4-chloro- quinazoline and aryl heterocyclic amines under microwave irradiation using 2-propanol as solvent. The advantages of the use of microwave irradiation in relation to the classical method were demonstrated.     

Microwave assisted synthesis of the fragrant compound Calone 1951

Calone 1951^®, 7-methyl-benzo[b][1,4]dioxepin-3-one, possesses a strong marine, ozone note with floral nuances and is synthesised via a three-step procedure using microwave irradiation. High yields were obtained, and reaction times reduced to a few minutes, allowing for an efficient and inexpensive synthesis of Calone 1951^®.     

微波辅助合成罗库溴铵重要中间体

罗库溴铵(Rocuronium bromide,Org-9426,Esmeron,Zemuron)为非去极化型雄箔类肌肉松弛药,由荷兰欧加农公司研究开发,1994年批准上市.罗库溴铵因具有起效快、体内无蓄积、不良反应小等特点而被广泛用于临床外科手术中~([1-2]).     

Microwave assisted synthesis and crystal structures of 2-imidazolines and imidazoles

A series of 2-imidazolines and imidazoles has been synthesized using green synthetic methodologies. The preparation of 2-imidazolines was performed by cyclization of nitriles with ethylenediamine. The use of microwave irradiation in solvent-free conditions enabled 2-imidazolines to be obtained in high yields within short reaction times. Aromatization of imidazoles was performed under microwave irradiation in toluene and using Magtrieve™ as the oxidant. The X-ray structures for five of these derivatives are provided. In all cases, the molecules are assembled into chains through N-H?N hydrogen bonds.     

Microwave assisted synthesis of substituted furan-2-carboxaldehydes and their reactions

A series of 5-unsubstituted and 5-substituted furfurylidenes have been prepared, under thermal and non-thermal microwave irradiation methods, via condensation of furfural and its derivatives with some of active methylene compounds. Furthermore, various condensate products from these furfurylidenes, which contain halogen or sulpher atoms, were also prepared. Structural elucidation of the synthesized compounds were determined on the basis of various spectroscopic methods.     

氨基甲酸酯型石胆酸分子裂缝的微波合成

利用人工受体与适当底物间的分子识别以建立仿生模型的研究已成为生物有机化学的前沿领域之一。作为一类新型的人工受体,分子裂缝近年来在分子识别、生物传感、外消旋体的拆分、分子器件等领域引起越来越多的关注[1-3]。胆甾因其具有刚性的凹面结构和固有的手性,是构筑钳形人工