Synthesis of Open-Resorcinarene Dendrimers with L-serine(ibuprofen) Derivatives

: A new class of dendrimers with open-resorcinarenes has been synthesized in good yields (77-85%). The open-resorcinarenes showed a high capacity for functionalization, having eight hydroxyl groups. The Williamson reaction with N,N-bis(2-azidoethyl)-2-bromo acetamide did not show any steric effect, obtaining sixteen azide terminal groups, which gave us the possibility to obtain a high molecular weight dendrimer via the azide-alkyne click reaction with prop-2-yn-1-yl-(ibuprofen)L-serinate derivatives to obtain the triazole ring spacers and the L-serinate(ibuprofen) derivatives as terminal groups. Also, we carried out the deprotection reaction of the L-serinate moiety terminal groups of the dendrimer 10 in good yields (95%). Three novel open-resorcinarene den-drimers with sixteen ibuprofen-L-serinate derivatives and hydroxyl, tert-butyl, and carboxylic acid; therefore, with three different terminal groups, with possible nanomedical activity are reported.

An efficient bifunctional ionic liquid [BIL] as solvent and catalyst system for O-alkylation of phenols under solvent-free condition- An environmental benign approach

: Bifunctional ionic liquid [BIL] was found to be a highly effective catalyst for the ether synthesis without any inorganic base or solvent. By this protocol, different aryl substitutions were reacted with different phenol in good to excellent yields. The BIL is reusable without any loss in catalytic activity for nine consecutive cycles. Background: The Williamson reaction is a convenient renovation in fine chemical synthesis since the ethers are important in both bulk and fine industrial chemicals preparation and academic applications. Objective: The aim of this study is to highlight the use of BIL to synthesize mixed ethers using substituted phenols and to study the reusability in the next cycle. Method: The mixture of the phenol (1mmol), alcohol (1.2 mmol) and BIL ionic liquid (0.3 mol%) was added in to round-bottomed flask (100 mL) with continuous stirring for 1 hour. Results: The products obtained were phenol and substituted phenols containing withdrawing substituents in respectable yields. However, the reactions involving substituted phenols containing electron-donating groups often afford the corresponding products in low yields. Conclusion: BIL is found to be an effective catalyst in the etherification of various unsymmetrical ethers under mild conditions. Bifunctional ionic liquid as a solvent and catalyst will show real rewards by providing a ‘green’ method with the safer procedure, less reaction time periods, mild conditions, separation easy, and ionic liquid recycle.

Synthesis of 4-(2H-[1,2,4]-Triazol-5-ylsulfanyl)-1,2-dihydropyrazol-3-one via Ring-Switching Hydrazinolysis of 5-Ethoxymethylidenethiazolo [3,2-b][1,2,4]triazol-6-one

4-(1H-[1,2,4]-Triazol-5-ylsulfanyl)-1,2-dihydropyrazol-3-one (4) was synthesized with a yield of 55% via ring-switching hydrazinolysis of 5-ethoxymethylidenethiazolo[3,2-b][1,2,4] triazol-6-one (3) in ethanol medium. The initial 1H-[1,2,4]-triazole-3-thiol (1) was modified via a two-step reaction: S-alkylation with chloroacetic acid under Williamson reaction conditions, and further one-pot cyclization–condensation with triethylorthoformate in the acetic anhydride medium, yielding compound 3. The structures of compounds 3 and 4 were confirmed by LC-MS, NMR spectra and a single X-ray diffraction analysis (for compound 4).

Synthesis of Well-Defined Three-Arm Star-Branched Polystyrene through Arm-First Coupling Approach by Atom Transfer Radical Polymerization

Here we describe a simple route to synthesize three-arm star-branched polystyrene. Atom transfer radical polymerization technique has been utilized to yield branched polystyrene involving Williamson coupling strategy. Initially a linear polymeric chain of predetermined molecular weight has been synthesized which is further end-functionalized into a primary alkyl bromide moiety, a prime requisition for Williamson reaction. The end-functionalized polymer is then coupled using 1,1,1-tris(4-hydroxyphenyl)ethane, a trifunctional core molecule, to give well-defined triple-arm star-branched polystyrene.

Construction of semi-fluorinated amphiphilic graft copolymer bearing a poly(2-methyl-1,4-bistrifluorovinyloxybenzene) backbone and poly(ethylene glycol) side chains via the grafting-onto strategy

Amphiphilic graft copolymers bearing a hydrophobic PMBTFVB backbone and hydrophilic PEG side chains were synthesized by Williamson reaction through the grafting-onto strategy.

Synthesis of Some new 2-(4-Aryliminophenoxy)N-Arylacetamide Via p-hydroxy benzaldehyde.

Chloroacetamide derivatives (2a-g) have been prepared through reaction of chloroacetyl chloride(1) (which prepared by the reaction of chloroacetic acid with thionyl chloride) with primary aromatic amines and sulfa compounds to afford compounds (2a-g) which then reacted with p-hydroxy benzaldehyde via Williamson reaction to obtaine the new compounds 2-(4-formyl phenoxy)-N-aryl acetamide (3a-g). Finally , compounds (3a-g) will be use as a good synthon to prepare the Schiff bases represented by compounds 2-(4-aryliminophenoxy)-N-arylacetamide (4a-g). through , reaction with some primary aromatic amine. All the prepared compounds were investigated by the available physical and spectroscopic methods.