Graphical abstract

Urea is one of the most used nitrogen fertilizers worldwide.

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Herein, we present a mechanistic study on tert-butyl hydroperoxide-promoted guanylation of thioureas by monitoring short lifetime intermediates using electrospray ionisation/time-of-flight high resolution mass spectrometry (ESI-Q-TOF HRMS).Moreover, 1 H nuclear magnetic resonance data allowed us to access kinetic parameters for the main species involved which, allied to the HRMS results, furnished valuable insights over previously reported observations. The results suggested an addition/elimination mechanism involving the aminoiminomethanesulphinic acid, RNC(SO 2 H)NHR′, and the nucleophilic amine as the main pathway to yield the guanidine. Noteworthy, benzoylthiourea consumption rate presented a nonlinear kinetic behaviour, while t BuOOH and the nucleophilic amine consumptions were found to follow second-order kinetics.

Herein, twenty-six benzoylthioureas were evaluated for their antimicrobial activity against different bacterial and fungal species. Two 4-substituted benzoylthiourea, one benzoylurea and one benzoylguanidine derivatives were further synthesized to identify the most promising compound. Eight compounds were active against at least one microbial species tested. N-(butylcarbamothioyl)-benzamide (1 e) exhibited the best antimicrobial activity towards Streptococcus agalactiae (group B Streptococcus-GBS), including clinical isolates susceptible or resistant to clindamycin and/or erythromycin and azithromycin.1 e presented a bacteriostatic effect, causing morphological and ultrastructural alterations on planktonic cells, and decreased the metabolic activity of GBS biofilms. No hemolytic and cytotoxicity to mammalian cells were detected for 1 e, that also displayed drug-likeness properties. Molecular docking was performed on Streptococcus pneumoniae enoyl-ACP reductase obtained by homology modeling. 1 e showed relevant interactions with the GBS enoyl-ACP reductase enzyme. N-(butylcarbamothioyl)-benzamide may be a good starting point for the development of new antimicrobials against GBS.

Background: New drugs and strategies to treat tuberculosis (TB) are urgently needed. In this context, thiourea derivatives have a wide range of biological activities, including anti-TB. This fact can be illustrated with the structure of isoxyl, an old anti-TB drug, which has a thiourea as a pharmacophore group. Objective: The aim of this study is to describe the synthesis and the antimycobacterial activity of fifty-nine benzoylthioureas derivatives. Methods: Benzoylthiourea derivatives have been synthesized and evaluated for their activity against Mycobacterium tuberculosis using the MABA assay. After that, a structure-activity relationship study of this series of compounds has been performed. Results and Discussion: Nineteen compounds exhibited antimycobacterial activity between 423.1 and 9.6 μM. In general, we observed that the presence of bromine, chlorine and t-Bu group at the para-position in benzene ring plays an important role in the antitubercular activity of Series A. These substituents were fixed at this position in benzene ring and other groups such as Cl, Br, NO2 and OMe were introduced in the benzoyl ring, leading to the derivatives of Series B. In general, Series B was less cytotoxic than Series A, which indicates that the presence of a substituent at benzoyl ring contributes to an improvement in both antimycobacterial activity and toxicity profiles. Conclusion: Compound 4c could be considered a good prototype to be submitted to further structural modifications in the search for new anti-TB drugs, since it is 1.8 times more active than the first line anti-TB drug ethambutol and 0.65 times less active than isoxyl.

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In the title compound, C6H10N2OS, the 2-sulfanylideneimidazolidin-4-one fragment is essentially planar (r.m.s. deviation = 0.0033 Å). In the crystal, one amino group is involved in N—H⋯O hydrogen bonding, which links pairs of mol­ecules into inversion dimers, while the other amino group generates weak N—H⋯S hydrogen bonds, which link these dimers into chains in [10-1]. The chains are further aggregated into layers parallel to the ac plane through weak C—H⋯O inter­actions.