Three new compounds of amidophosphoric acid esters with a [OCH2C(CH3)2CH2O]P(O)[X] segment (where X=cyclopentylamido (1), 2‐aminopyridinyl (2) and pyrrolidinyl (3)) were synthesized and studied using FT‐IR and 31P/13C/1H NMR spectroscopies and single‐crystal X‐ray diffraction analysis. The compounds crystallize in the triclinic space groups Ptrue1‾ for 1 and 3 and in the orthorhombic space group Pca21 for 2, where the asymmetric unit consists of three symmetrically‐independent molecules for 1 and one molecule for 2 and 3. The intermolecular interactions and supramolecular assemblies are assessed by Hirshfeld surface analysis and enrichment ratios. The results reveal that the substituent effect plays an important role in directing the supramolecular structures. The presence of the aromatic substituent aminopyridine in 2 providing the C−H…π interactions leads to a larger variety in interactions including H…H, H…O/O…H, H…C/C…H and H…N/N…H contacts, whereas the packings of the compounds 1 and 3 bearing aliphatic substituents only include H…H and H…O/O…H contacts. The enrichment ratios affirm the importance of O…H/H…O contacts reflecting the hydrogen bond N−H…O interactions to be the enriched contacts. Compounds 1–3 were also investigated along with five similar reported structures with a [OCH2C(CH3)2CH2O]P(O) segment for their inhibitory behavior against SARS‐CoV‐2. The molecular docking results illustrate that the presence of the aromatic amido substituent versus the aliphatic type provides a more favorable condition for their biological activities.

Background and Aim: The acceptable noise level (ANL) assesses the noise that a person can tolerate during a running speech. Although it is a strong test, it has not yet become popular in clinical practice. One of the reasons is its contradictory results. Since it is a psychoacoustic test, psychological factors can affect its output. Investigation of these factors can provide more accurate results. This study aims to investigate the effects of noise and work-related fatigue on the ANL in normal-hearing people. Methods: Participants were the male workers in the administration (n = 26) and production (n = 26) departments of an automotive manufacturing industry in Iran. They were evaluated before and after leaving the workplace in order to determine the effects of noise exposure, fatigue as well as their simultaneous effects on the ANL. Results: In both groups, the ANL showed a significant increase after work compared to its level before work, and the background noise level (BNL) was significantly decreased. There was no significant difference in the BNL between administration and production groups before work. The most comfortable level (MCL) showed no significant increase. Moreover, the MCL changes were not significantly different in the production group compared to administration group, but the BNL and ANL changes were significantly higher. Conclusion: Noise exposure and work-related fatigue affect the ANL. During the ANL test, earlier exposure to noise and the amount of fatigue should be controlled.   Keywords: Exposure to noise; fatigue; acceptable noise level

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