Magnetic Nanoparticle Assisted Bulk Scale Synthesis of Quinazoline Synthon

Abstract

<jats:p>Quinazolines are unique class of compounds possessing exceptional antibacterial activity. Quinazolines class obtains its typical antibacterial activity due to its toxicity from‘hetero’ ring. Known to be the last line of protection against deadly TB bacteria, there are about twenty different quinazoline compounds used in pharma industry. One of the widely used precursors for synthesis of these drugs is 4-chloro-2-phenylquinazoline. In the present research, aminobenzamide and benzoyl chloride are reacted to obtain the cyclized intermediate, 2-phenylquinazoline, which on subsequent treatment with POCl<jats:sub>3</jats:sub> forms in 4-cholro-2-phenyl quinazoline. This reaction takes about four days to finish with maximum yield of around 60%. A modification was done using silica coated magnetic nanoparticles (Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>@SiO<jats:sub>2</jats:sub>) as solid support to further improve the yields attaining about 80% and reduction of reaction time to half. Based on the results obtained, it was concluded that the solid support facilitates the adsorption of acid chloride and also provides the catalytic surface for condensation reaction, due to the acidic nature of the silica gel. The POCl<jats:sub>3</jats:sub> reaction uses the nanosilica surface to produce 4-chloro phenyl-2-qinazoline in 80% overall yield. The reason for improved yield could be increase in acidic surface area which could speed up the quinazoline cyclization. Though material chemistry supports are known to improve reaction yields, use of silica coated magnetic nanomaterials towards the quinazoline synthesis is reported for the first time. The characterization data of Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>@SiO<jats:sub>2</jats:sub> particles has shown that batch to batch consistency exists in synthesis and it can be used in the pharma industry.</jats:p>

Harnessing the Intriguing Properties of Magnetic Nanoparticles to Detect and Treat Bacterial Infections

“…MNPs have been widely used in the biological field in recent years due to their physical properties, good biocompatibility, and high binding capacity [8][9][10], including in vivo and in vitro bacterial detection and separation imaging [11], as well as the treatment of pathogenic bacteria. For example, magnetic materials were used to synthesize new structures [12] and new magnetic material composite nanoparticles with improved structural stability [13], biological activity [14], and antibacterial properties [15][16][17][18] to realize the separability and recyclability of MNPs [19][20][21].…”