2-[(S)-1,2,3,4-Tetrahydroisoquinolin-3-yl]acetic acid hydrochloride

Background: Quinolone scaffolds are widely used for the synthesis of a number of medicinal compounds with variety of biological activity. In view of the reported antimicrobial activity of various fluoroquinolones, the structure activity studies of various substituted quinolones, which proved the importance of the C-7 substituents to exhibit potent antimicrobial activities. Objective: Based on the structural activity relationship at C-7 position it was rationalized to design and synthesize new quinolone derivatives with increasing bulk at C-7 position of the main 6-fluoroquinolone scaffold. Methods: A novel series of 1-cyclopropyl-6-fluoro-4-oxo-7-{4-[2-(4-substituted-phenyl)- 2-(substituted)-ethyl]-1-piperazinyl}-1,4-dihydroquinoline-3-carboxylic acid derivatives were synthesized by reacting 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4- dihydroquinoline-3-carboxylic acid with 2-bromo-4-(substituted) acetophenone in the presence of sodium bicarbonate to obtain 1-cyclopropyl-6-fluoro-7-{4-[2-(4- substitutedphenyl)-2-oxoethyl]-1-piperazinyl}-4-oxo-1,4-dihydroquinoline-3-carboxylic acids 2a-2d. Compound 2a-2d underwent further reaction with different substituted hydrazide, hydroxylamine hydrochloride or methoxylamine in glacial acetic acid to give 3a-7d. In vitro antibacterial activity of the synthesized compounds 3a-7d was studied and the MIC value was determined by the broth dilution method. Result: Among all the synthesized compounds 3a-7d some compounds showed antimicrobial activity in comparison to the reference standard ciprofloxacin. Conclusion: The compound 6d showed the reasonable good antibacterial activity among all the tested compounds. To understand antibacterial data on structural basis and the interaction of binding sites with bacterial protein receptor, the docking studies were carried out using topoisomerase II DNA gyrase enzymes (PDB ID. 2XCT) by shrodinger's maestro program.

A solid phase extraction-based (SPE) procedure for simultaneous preconcentration of five tricyclic antidepressants (TCAs), amitriptyline hydrochloride (AMT), nortriptyline hydrochloride (NOR), doxepin hydrochloride (DOX), imipramine hydrochloride (IMI), and clomipramine hydrochloride (CLO) from water samples with determination by HPLC-DAD is proposed. Polymers were characterized by FT-IR, SEM, and thermogravimetric analysis. SPE-based methods were carried out by the preconcentration of 320.0 mL of TCAs at pH 7.0 (buffered with 0.01 mol L-1 phosphate buffer) through 70.0 mg of adsorbent packed into a SPE cartridge, followed by elution with 1.0 mL of ACN : MeOH : acetic acid solution (45 : 45 : 10% v/v). Higher preconcentration factors were obtained ranging from 117.9 to 372.2 and 207.1 to 396.1 by using poly(MAA-co-EGDMA) and poly(AA-co-EGDMA), respectively, yielding lower limits of detection (0.03 to 0.12 μg L-1) and (0.03 to 0.15 μg L-1). These outcomes show satisfactory detectability of SPE-based methods, with slightly better performance using poly(MAA-co-EGDMA). On the other hand, poly(AA-co-EGDMA) was able to preconcentrate TCAs in the presence of humic acid (7.0 mg L-1) without interference. The precision of methods assessed as RSD (%) was very similar, ranging from 1.7% to 16.3% for poly(MAA-co-EGDMA) and 1.7% to 13.4% for poly(AA-co-EGDMA). SPE cartridges packed with the polymers showed high reusability (52 cycles of preconcentration and elution) without losing adsorption efficiency. The methods were applied to determine TCAs in tap, lake, and stream water samples and the accuracy was attested by addition and recovery tests (86.7-116.0%), with determined nortriptyline ranging from 0.48 to 0.52 μg L-1 in lake water samples.

Collagen is the major component of the extracellular matrix in human tissues and widely used in the fabrication of tissue engineered scaffolds for medical applications. However, these forms of collagen gels and films have limitations due to their inferior strength and mechanical performance and their relatively fast rate of degradation. A new form of continuous collagen yarn has recently been developed for potential usage in fabricating textile tissue engineering scaffolds. In this study, we prepared the continuous electrochemical aligned collagen yarns from acid-soluble collagen that was extracted from rat tail tendons (RTTs) using 0.25 M acetic acid. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and Fourier transform infrared spectroscopy confirmed that the major component of the extracted collagen contained alpha 1 and alpha 2 chains and the triple helix structure of Type 1 collagen. The collagen solution was processed to monofilament yarns in continuous lengths by using a rotating electrode electrochemical compaction device. Exposing the non-crosslinked collagen yarns and the collagen yarns crosslinked with 1-ethyl-3-(-3-dimethyl-aminopropyl) carbodiimide hydrochloride to normal physiological hydrolytic degradation conditions showed that both yarns were able to maintain their tensile strength during the first 6 weeks of the study. Cardiosphere-derived cells showed significantly enhanced attachment and proliferation on the collagen yarns compared to synthetic polylactic acid filaments. Moreover, the cells were fully spread and covered the surface of the collagen yarns, which confirmed the superiority of collagen in terms of promoting cellular adhesion. The results of this work indicated that the aligned RTT collagen yarns are favorable for fabricating biotextile scaffolds and are encouraging for further studies of various textile structure for different tissue engineering applications.