A three‐phase solvent extraction system combined with deep eutectic solvent‐based dispersive liquid–liquid microextraction for extraction of some organochlorine pesticides in cocoa samples prior to gas chromatography with electron capture detection

A sample pretreatment method based on the combination of a three‐phase solvent extraction system and deep eutectic solvent‐based dispersive liquid–liquid microextraction has been introduced for the extraction of four organochlorine pesticides in cocoa samples before their determination by gas chromatography‐electron capture detection. A mixture of sodium chloride, acetonitrile, and potassium hydroxide solution is added to cocoa bean or powder. After vortexing and centrifugation of the mixture, the collected upper phase (acetonitrile) is removed and mixed with a few microliters of N,N‐diethanol ammonium chloride: pivalic acid deep eutectic solvent. Then it is rapidly injected into deionized water and a cloudy solution is obtained. Under optimum conditions, the limits of detection and quantification were found to be 0.011‐0.031 and 0.036‐0.104 ng/g, respectively. The obtained extraction recoveries varied between 74 and 92%. Also, intra‐ (n = 6) and interday (n = 4) precisions were less than or equal to 7.1% for the studied pesticides at a concentration of 0.3 ng/g of each analyte. The suggested method was applied to determine the studied organochlorine pesticide residues in various cocoa powders and beans gathered from groceries in Tabriz city (Iran) and aldrin and dichlobenil were found in some of them.     

Synthesis and structure determination of 7a-Aza-B-homostigmast-5-eno [7a, 7-d] tetrazole-3β-yl chloride (C29H47N4Cl)

7a-Aza-B-homostigmast-5-eno [7a, 7-d] tetrazole-3β-yl chloride (C₂₉H₄₇N₄Cl) was synthesized for its crystallographic analysis and to investigate the role of intra- and intermolecular interactions in steroids. It crystallizes in the monoclinic space group C2 with unit cell parameters: a = 38.481(2), b = 6.661(3), c = 11.111 (6) ?, β = 94.49 (4)^o; λ( MoKα) = 0.71069 ?, V = 2839(2) ?³, and Z = 4. The structure has been solved by direct methods using X-ray diffraction techniques. The final reliability index for the computed structure is 0.0597 for 1252 observed reflections. Except the five-membered ring, all other rings of the steroid nucleus exist in non-planar conformations. The structure is stabilized by C–H···N intermolecular interaction.Supplementary material CCDC-267926 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.an.uk/uk/conts/retrieving.html or from the Cambridge Crystallographic Data Centre (CCDC), 12 Union Road, Cambridge CB2 1EZ, United Kingdom; Fax: $+$44(0) 1223-336033; e-mail: deposit@ccdc.cam.ac.uk.     

One‐Pot Synthesis of 6,7‐Fused Steroidal Thiazoles in Cholestane Series

A convenient one‐pot synthesis of 2′‐amino‐ and 2′‐N‐phenylamino‐5α‐cholest‐6‐eno[6,7‐d]thiazole derivatives 4 ‐ 9 are reported. The synthesis involves the reaction of cholestan‐6‐ones 1 ‐ 3 with thiourea or phenylthiourea and iodine. The products have been characterized on the basis of IR, ¹H‐NMR and Mass, which find support in two cases from comparison with authentic samples.     

Derivatives of substituted 3‐trichlorogermylpropionic acid

The central Ge atoms in the structures of 3‐(2‐fluoro­phenyl)‐3‐(tri­phenyl­germyl)­propionic acid, [Ge(C₆H₅)₃(C₉H₈FO₂)], 3‐(2‐tolyl)‐3‐(tri‐4‐tolyl­germyl)­propionic acid, [Ge(C₇H₇)₃(C₁₀H₁₁O₂)], and 3‐(4‐tolyl)‐3‐(tri­benzyl­germyl)­propionic acid, [Ge(C₇H₇)₃(C₁₀H₁₁O₂)], are four‐coordinate with slightly distorted tetrahedral geometry. The Ge—Csp³ distances [1.970 (3)–1.997 (3) Å] are significantly longer than the Ge—C_aromatic distances [1.940 (3)–1.959 (2) Å]. In all three structures, the mol­ecules form dimeric pairs about inversion centres through strong hydrogen‐bonding interactions between carboxyl­ic acid groups.     

In silico ADME predictions and in vitro antibacterial evaluation of 2-hydroxy benzothiazole-based 1,3,4-oxadiazole derivatives

In the present work, a library of fifteen 2-hydroxy benzothiazole-linked 1,3,4 -oxadiazole derivatives have been synthesized and confirmed using different analytical techniques. All of the synthesized compounds have been tested for antibacterial and in silico pharmacokinetic studies for the first time. From the ADME predictions, compound 4 showed the highest in silico absorption percentage (86.77%), while most of the compounds showed more than 70% absorption. All of the compounds comply with the Lipinski rule of 5, suggesting that the compounds possess good drug likeness properties upon administration. Furthermore, all of the compounds follow the Veber rule, indicating good bioavailability and good intestinal absorption. The antibacterial results exhibited excellent to moderate activity. Compounds 5 , 9 , 12 , 14 , 15 , 16 , and 17 were the most active compounds against the tested bacterial strains. Compound 14 showed comparable MIC 6.25 ±0.2 μg/disc to the standard drug amoxicillin against the tested Gram-positive bacterial strains. Compounds 5 , 14 , 17 exhibited MIC 12.5 ±0.8 μg/disc, which was comparable to the standard drug against E. faecalis . It can be concluded that the synthesized compound could be used as a lead molecule in the development of new antibacterial agents with high efficacy.     

Design,Synthesis, Crystal Structure,In Vitro and In Silico Evaluation of New N′-Benzylidene-4-tert-butylbenzohydrazide Derivatives as Potent Urease Inhibitors

Background: Hydrazides play a vital role in making biologically active compounds in various fields of chemistry. These determine antioxidant, antidepressant, antimalarial, anti-inflammatory, antiglycating, and antimicrobial activity. In the present study, twenty-three new N′ benzylidene-4-(tert-butyl)benzohydrazide derivatives (4–26) were synthesized by the condensation of aromatic aldehydes and commercially available 4-(tert-butyl)benzoic acid. All the target compounds were successfully synthesized from good to excellent yield; all synthesized derivatives were characterized via spectroscopic techniques such as HREI-MS and ¹H-NMR. Synthesized compounds were evaluated for in vitro urease inhibition. All synthesized derivatives demonstrated good inhibitory activities in the range of IC₅₀ = 13.33 ± 0.58–251.74 ± 6.82 µM as compared with standard thiourea having IC₅₀ = 21.14 ± 0.425 µM. Two compounds, 6 and 25, were found to be more active than standard. SAR revealed that electron donating groups in phenyl ring have more influence on enzyme inhibition. However, to gain insight into the participation of different substituents in synthesized derivatives on the binding interactions with urease enzyme, in silico (computer simulation) molecular modeling analysis was carried out.