Synthesis and Research of Properties of Polyether Ether Ketone

Polyether ether ketones based on 4,4'-difluorobenzophenone and hydroquinone in sulfolane medium in the presence of anhydrous potassium carbonate were synthesized by the method of high-temperature polycondensation. The rheological, thermal, electrical and physical-mechanical properties are investigated. It is shown that, at processing temperatures, the molecular weight of polyether ether ketones synthesized in sulfolane increases, apparently due to the branching processes of the polymer chain.

Synthesis, Characterization, Antimicrobial Screening of 5-Bromobenzofuranyl Aryl Ureas and Carbamates

Present work reports the biologically important benzofuran aryl ureas and carbamates. The benzofuran ring was formed by reacting bromo salicylaldehyde with diethyl bromomalonate in presence of dry acetone and anhydrous potassium carbonate to obtain 5-bromo-2-ethyl carboxylate (1). The obtained ester (1) was converted into corresponding hydrazide (2) by treating with hydrazine hydrate in ethanol. Compound 2 was then converted into 5-bromobenzofuran-2-carbonyl azide (3) by treating it with sodium nitrite in dioxane and acetic acid. The compound 3 is converted into 5-bromobenzofuranyl aryl ureas (4a-e) after treating primary amines and anhydrous toluene. 5-Bromobenzofuranyl aryl carbamate (5) and ethyl carbamate (6) were also synthesized by treating compound 3 with substituted phenol in toluene and ethanol respectively. All the compounds were characterized by NMR, IR and screened for antimicrobial activities.

An Expeditious and Safe Synthesis of Some Exocyclic α,β-Unsaturated Ketones by Microwave-Assisted Condensation of Cyclic Ketones with Aromatic Aldehydes over Anhydrous Potassium Carbonate

A rapid, efficient, and solvent-free methodology for synthesis of exocyclic α,β-unsaturated ketones of the categories E-3-arylidene-4-chromanones, E-2-arylidene-1-tetralones, E-2-arylidene-1-indanones, E-3-cinnamylidene-4-chromanones, E-2-cinnamylidene-1-tetralones, E-2-cinnamylidene-1-indanones, α,α′-(E,E)-bis(arylidene)-cycloalkanones, and α,α′-(E,E)-bis(cinnamylidene)-cycloalkanones has been developed through cross-aldol condensation of the constituent cyclic ketones and aldehydes by microwave irradiation over anhydrous potassium carbonate. However, for condensation of 1-thio-4-chromanones with aromatic aldehydes by this method, the initially formed exocyclic α,β-unsaturated ketone has been found to undergo isomerization yielding 3-(arylmethyl)thiochromones.

5-Aminouracil as a Building Block in Heterocyclic Synthesis: Part I. One-pot Synthesis of Pyrimido[5,4-b]quinolin-2,4,9-triones under Microwave Irradiation without Catalyst

A series of 6,7,8,10-tetrahydropyrimido[5,4-b]quinolin-2,4,9-(1H,3H,5H)-triones 6 were synthesized through one-pot condensation of 5-aminouracil, aldehydes and dimedone in DMF under microwave irradiation without catalyst. The products 6a, d were oxidized to the 7,8-dihydro-pyrimido- [5,4-b]quinolin-2,4,9-(1H,3H,6H)-triones 11a, b. Treatment of 6a, d and/or 11a, b with ethyl iodide in the presence of anhydrous potassium carbonate gave the ethylated derivatives 12a, b and 13a, b, respectively. The structures of the products were confirmed by elemental analyses, IR, MS, 1H, and 13C NMR spectra.