One-Pot Multicomponent Synthesis of Thiourea Derivatives in Cyclotriphosphazenes Moieties

In this study, hexasubstituted thiourea was carried out via reaction of isothiocyanato cyclophosphazene intermediates with a series of aromatics amines and amino acids in a one-pot reaction system. The reaction was not as straightforward as typical thiourea synthesis. Six unexpected thiourea derivatives 3a-f were formed in the presence of cyclotriphosphazene moieties in good yields (53-82%). The structures of 3a-f were characterized by elemental analysis and FTIR, 1H, 13C, and 31P NMR spectroscopies. The occurrence of reverse thioureas formation in a one-pot reaction system is discussed. The possible binding interaction of the synthesised thiourea 3a-b in comparison to the predicted phenyl thiourea 5a-b and the targeted 4a with enzyme enoyl ACP reductase (FabI) is also discussed. Molecular docking of the targeted hexasubstituted thiourea 4a is able to give higher binding affinity of -7.5 kcal/mol compared to 5a-b (-5.9 kcal/mol and -6.3 kcal/mol) and thiourea 3a-b (-4.5 kcal/mol and -4.7 Kcal/mol). © 2017 Zainab Ngaini et al

Bacteriostatic activities of N-substituted tris-thioureas bearing amino acid and aniline substituents

A series of tri-substituted thiourea derivatives were synthesized by the reaction of 1,3,5-triacetylbenzoyl isothiocyanate with aminoacids and aniline derivatives. All thiourea derivatives were characterized by FT-IR, 1H and 13C NMR spectroscopy. Antibacterial activities against wild-type Escherichia coli American Type Culture Collection 8739 were determined by use of the turbidimetric methodto evaluate the effect of varying amino groups on the synthesized thioureas. Tris-thiourea derivatives bearing ortho-chloroaryl substituents showed excellent antibacterial activity against E. coli with minimal inhibitory concentration (MIC) of 96 ppm. The optimum inhibition was dependent on the type of amines and the position of the halogen in aniline

Synthesis, Biological Properties and Comparative Molecular Docking Evaluation Studies of 1,3 and 1,4 Bis-Thiourea Derivatives as Potential Antimicrobial Resistant Agents

Introduction: Thiourea is one of the promising class of compounds that possess various pharmacological activity including antibacterial properties. Objective: The rise of microbial resistant drugs has triggered an alarming response among researchers to developed new drugs with effective biological properties. The position of substituents and active pharmacophores play an important role in designing a lead compound with effective biological properties. Methods: In this study, two series of 1,3-bis-thiourea derivatives (3a-l) and 1,4 bis-thiourea derivatives (4a-l) were synthesised from the reaction of isophthaloyl diisothiocyanate intermediates with halogenated amines. Results: The comparative studies of antibacterial properties of 3a-l and 4a-l against the growth of E. coli showed the minimum inhibition of 3g (7mm inhibition) and 4g (18mm inhibition) compared to standard drug ampicillin (16mm inhibition). Molecular docking evaluation against E. coli DNA gyrase B showed strong binding interaction of 4g with binding affinity -6.7 kcal/mol and more hydrogen bond compared to 3g with binding affinity -6.4 kcal/mol). Conclusion: The study is significant in drug design in particular for the development of potential drugs with antimicrobial resistant properties

Assessment of Practical and Scientific Writing Skills for Pre-University Students through Project-Based Learning

Chemistry is one of the STEM (science, technology, engineering, and mathematics) subjects that has been perceived as an unattractive subject among students due to its scientific theories and practices in a laboratory. Practical and scientific writing skills are two crucial components in chemistry courses, including at the Pre-University level, thus requiring educators to design activities that integrate both skills in chemistry learning. This article describes the assessment using a projectbased learning approach to assess students’ practical and scientific writing skills for the Organic Chemistry course at the Universiti Malaysia Sarawak Foundation in Science program. A total of 72 PreUniversity science students participated in a Chemistry Group Project assessment. The students were divided into 6 groups and asked to write a proposal on the basis of a chosen title, conduct laboratory work, collect data, and prepare a final report. The assessment was conducted in a single semester from learning week 1 to learning week 17. Results of this study were collected through the submitted proposal, final reports, practical sessions, and students’ feedback. Students obtained good marks for practical and scientific writing with average marks of 84.9% and 84.4%, respectively. The results revealed that implementing the Chemistry Group Project as project-based learning leads to increased performance in practical and scientific writing skills and social skills among Pre-University students. Therefore, the Chemistry Group Project should be conducted as one of the learning activities and practical approaches at the Pre-University level

Research based Learning through Immersive Face to Face Interaction

Group project for PRK1026 Chemistry II was implemented as researchbased learning through immersive face to face interaction among students and facilitator. The main activities include planning by writing proposal, conducting laboratory activities, interpretation of scientific data, followed by producing a scientific article. All pre-university students are required to complete this project as a team which cover topics related to Chemistry Learning Units in Semester Two

Synthesis And Characterization Of Bis Thiourea Derivatives Another Antibacterial Activity

Thiourea and its derivatives are well known as potent antibacterial and antifungal agents. This research focused on the synthesis of bis thiourea derivatives with two thiourea groups resulting from the reactions of 3-acetylbenzoyl isothiocyanate intermediate with appropriate amine group from certain amino acids and aniline. Five bis thiourea derivatives have been synthesized. The successfully synthesized compounds were characterized using FTIR, IH NMR and DC NMR and found to be in highly purity compound. Antibacterial assay was carried out using turbidimetric method against the growth of Escherichia Coliform sp. (E. coli). However, the result indicated that the newly synthesized bis thiourea derivatives showed poor antibacterial activity against E. coli. The effect of the structure of the investigated compounds on the antibacterial activity is discussed

Synthesis and characterisation of multi-substituted thiourea derivatives and their antibacterial activities

Two series of bis-substituted thiourea derivatives 40a-e and tri-substituted thiourea derivatives 42a-i have been successfully synthesised by reaction of isothiocyanate intermediates with series of amines. 1,3-benzenedicarbonyl chloride 9 and 1,3,5- benzenetricarbonyl chloride 46 were utilized as a scaffold to prepare the isothiocyanate intermediates and formed 40a-e and 42a-i respectively. The synthesis of proposed hexasubstituted thiourea derivatives was done by reacting hexachlorocyclotriphosphazene 4 as a precursor and formed six unexpected thiourea derivatives 43a-f. The preparation of unexpected thiourea products was triggered by the formation of HCl in the reaction system due to existence of free chlorine atoms which mildly dissociated from 4. The synthesis of the proposed hexa-substituted thiourea derivatives was continued via aminolysis reaction of 4 with single thiourea compounds 43a-i but the reaction was unsuccessful. All synthesised products were characterised using CHNS elemental analysis, FTIR, 1H NMR, 13C NMR and 31P NMR spectroscopic techniques. Antibacterial assay of all synthesised products was carried out using turbidimetric method against the growth of Escherichia Coliform sp. (E. coli). The results indicated that only compounds 42a-i which bear three thiourea moieties showed significant antibacterial activities. The effects of constituents and structure of the investigated compounds on the antibacterial performance were discussed

Scienceploration 2023

The Scienceploration Camp is an initiative of the Centre for Pre-University Studies, UNIMAS (PPPU), which aims to increase the interest in science among secondary school students. It is also an effort taken by PPPU towards the achievement of Sustainable Development Goals 4 in providing equal quality education and promoting lifelong learning opportunities for all. On top of that, this camp supports Sarawak’s Digital Economy Strategy in nurturing an integrated ecosystem to foster inclusive digital society, by building the right foundations to grow our local digital economy