ChemInform Abstract: Novel Synthetic Methodologies. Part 231. Copper-Mediated C-H Activation of 1,3,4-Oxadiazoles with 1,1-Dibromo-1-alkenes Using PEG-400 as a Solvent Medium: Distinct Approach for the Alkynylation of 1,3,4-Oxadiazoles.

ChemInform ◽  
2012 ◽  
Vol 43 (22) ◽  
pp. no-no
Author(s):  
Gandolla Chinna Reddy ◽  
Penagaluri Balasubramanyan ◽  
N. Salvanna ◽  
Biswanath Das
Author(s):  
Meka Lingam ◽  
Vobalaboina Venkateswarlu

The low aqueous solubility of celecoxib (CB) and thus its low bioavailability is a problem.    Thus, it is suggested to improve the solubility using cosolvency and solid dispersions techniques. Pure CB has solubility of 6.26±0.23µg/ml in water but increased solubility of CB was observed with increasing concentration of cosolvents like PEG 400, ethanol and propylene glycol. Highest solubility (791.06±15.57mg/ml) was observed with cosolvency technique containing the mixture of composition 10:80:10%v/v of water: PEG 400: ethanol. SDs with different polymers like PVP, PEG were prepared and subjected to physicochemical characterization using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), solubility and dissolution studies. These studies reveals that CB exists mainly in amorphous form in prepared solid dispersions of PVP, PEG4000 and PEG6000 further it can also be confirmed by solubility and dissolution rate studies. Solid dispersions of PV5 and PV9 have shown highest saturation solubility and dissolution rate


2019 ◽  
Vol 23 (16) ◽  
pp. 1738-1755
Author(s):  
Humaira Y. Gondal ◽  
Zain M. Cheema ◽  
Abdul R. Raza ◽  
Ahmed Abbaskhan ◽  
M. I. Chaudhary

Following numerous applications of Wittig reaction now functionalized phosphonium salts are gaining attention due to their characteristic properties and diverse reactivity. This review is focused on α-alkoxyalkyl triphenylphosphonium salts: an important class of functionalized phosphonium salts. Alkoxymethyltriphenylphosphonium salts are majorly employed in the carbon homologation of carbonyl compounds and preparation of enol ethers. Their methylene insertion strategy is extensively demonstrated in the total synthesis of a wide range of natural products and other important organic molecules. Similarly enol ethers prepared thereof are important precursors for different organic transformations like Diels-Alder reaction, Claisen rearrangement, Coupling reactions, Olefin metathesis and Nazarov cyclization. Reactivity of these α-alkoxyalkylphosphonium salts have also been studied in the nucleophilic substitution reactions. A distinctive application of this class of phosphonium salts was recently reported in the phenylation of carbonyl compounds under very mild conditions. Synthesis of structurally diverse alkoxymethyltriphenylphosphonium salts with variation in alkoxy groups as well as counter anions are reported in literature. Here we present a detailed account of different synthetic methodologies for the preparation of this unique class of quaternary phosphonium salts and their applications in organic synthesis.


Author(s):  
Maryam Aisyah Abdullah ◽  
Siti Munirah Mohd Faudzi ◽  
Nadiah Mad Nasir

Abstract:: Medicinal chemists have continuously shown interest in new curcuminoid derivatives, the diarylpentadienones, owing to their enhanced stability feature and easy preparation using a one-pot synthesis. Thus far, methods such as Claisen-Schmidt condensation and Julia-Kocienski olefination have been utilised for the synthesis of these compounds. Diarylpentadienones possess a high potential as a chemical source for designing and developing new and effective drugs for the treatment of diseases, including inflammation, cancer, and malaria. In brief, this review article focuses on the broad pharmacological applications and the summary of the structure-activity relationship of molecules which can be employed to further explore the structure of diarylpentadienone. The current methodological developments towards the synthesis of diarylpentadienones are also discussed.


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