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• A highly efficient method of the synthesis. • The use of an eco-friendly solvent. • Easy implementation of the reaction. • Purification of compounds without column chromatography. • In-depth theoretical study. Isoxazolone derivatives exhibit numerous biological and pharmacological activities. The search of new procedures for the synthesis of this class of heterocycles is still relevant. Thus we propose a new efficient method for the preparation of a series (4a-4j) of 3-methyl-4-arylidene-isoxazol-5(4 H)-ones by the three-component reaction between aromatic aldehydes, ethyl acetoacetate and hydroxylamine hydrochloride, catalyzed by sulfamic acid as an inexpensive, commercially available and easy to handle catalyst. The expected molecules were obtained, in general, in good yields in relatively short reaction times and their structures were elucidated by 1H and 13C NMR and high resolution mass spectrometry for the new compounds. In addition, the structure of compound 4c was confirmed by X-ray diffraction and its Hirshfeld surface analyzed. The work is complemented by theoretical studies including DFT calculations, IR vibrations and UV–Vis electronic transitions analyzes and ADMET properties. In Silico physicochemical properties as well as molecular docking were also carried out. [ABSTRACT FROM AUTHOR]

• Sulfamic acid functionalized MIL-53(Al) was prepared via the solvothermal method. • The catalyst exhibited high adsorption capacities for CR, MB and Pb(II). • 50 wt% SA@MIL-53(Al) exhibited excellent catalytzic efficiency of 92.0 %. • Thermodynamic parameters indicated the physical adsorption of the studied pollutants. This study proposed the facile synthesis of sulfamic acid functionalized MIL-53 (Al) (SA@MIL-53(Al)) nanocomposite for dual-functional pollutant removal and catalytic synthesis. The composite was synthesized through a facile, straightforward, and one-step solvothermal process. Furthermore, different analysis techniques like XRD, SEM, XPS, FT-IR, and TGA were applied to examine the prepared composites' structure properties, confirming the successful preparation of functionalized frameworks. Several factors, including the initial concentration of pollutants, adsorbent dosage, pH, and pH pzc, have been established to optimize the suitable parameters for adsorption. 25 wt.% SA@MIL-53(Al) has the greatest adsorption capacities of 146.5, 97.7, and 35.5 mg g −1 for removing MB, CR dyes, and Pb (II), respectively. The rate-limiting steps were also discussed, and the experimental adsorption measurements obeyed the Langmuir and the pseudo-second-order kinetic models. Moreover, the fabricated composites were used as catalysts to produce 3,4-dihydropyrimidinone (3,4-DHP). 50 wt.% SA@MIL-53(Al) demonstrated the highest efficiency, nearly 92.0 %, with great durability and stability. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of thiazole derivatives using green synthetic potential of PEG-400 and sulfamic acid. • Computational insights into structural analysis, HOMO-LUMO, electronic parameters, spectroscopic (UV–Vis and IR), MESP, Mulliken charges. • Solvent study on UV–Vis spectroscopic data and prediction of various absorption bands. • Antibacterial, antifungal, antioxidant and hemolytic study. • ADME and toxicity prediction. In the present investigation, we report a combined computational and experimental study of eight thiazole derivatives (4a-4h) obtained from 3,4-dihydronaphthalen-1(2 H)-one. A green chemistry protocol comprising PEG-400 and sulfamic acid was employed for the synthesis of eight diverse thiazole derivatives from 3,4-dihydronaphthalen-1(2 H)-one, thiosemicarbazide and eight various phenacyl bromides. The synthetic strategy provides benefits like short reaction time, high yield, and non-chromatographic purification. The compounds were structurally confirmed on the basis of IR, 1HNMR and 13C NMR. The obtained thiazole derivatives were studied using the Density Functional Theory (DFT) method employing B3LYP/6–311G(d,p) level of theory for optimization and Time-Dependent DFT (TD-DFT) approach for examining electronic energies and UV–Vis characteristics. Various computational parameters like bond length, bond angles, HOMO, LUMO, MESP, Mulliken charges, and global reactivity descriptors are obtained and discussed. The UV–Vis study in gas phase and DMSO solvent was investigated to obtain various insights such as absorption energies oscillator strength, configurations and transitions of examined thiazole derivatives. The effect of polar solvent has augmented the absorption wavelength of all studied thiazole derivatives. The experimental and simulated UV–Vis data correlate with each other prompting the effectiveness of the computed method. The scaled and experimental wavenumbers provided the appropriate assignment of various vibrational signals. The antibacterial study was performed against E. coli, P. aeruginosa , and S. aureus which demonstrated the strong antibacterial potential against S. aureus. The antifungal study against C. albicans revealed that these compounds are poor antifungal agents. The DPPH and OH radical assays were used to establish the% radical scavenger effects and results showed that these derivatives are good antioxidant agents. The% hemolytic activity of the tested compounds showed that all compounds fall within the acceptable toxicity limit. Importantly in slico ADME and toxicity prediction studies of these compounds highlighted good ADME profile with no hepatotoxicity, immunotoxicity and cytotoxicity. [Display omitted] [ABSTRACT FROM AUTHOR]

Some new pyridopyrimidinones derivatives (PPDs) namely (E)-2-(hexadecylthio)-8-(4-methoxybenzylidene)-5-(4-methoxyphenyl)-1,2,3,6,7,8-hexahydro-4H-cyclopenta[5,6] pyrido[2,3-d] pyrimidin 4 -one (Compound I) and (E)-8-(4-methoxybenzylidene)-5-(4-methoxyphenyl) -2-thioxo-1,2,3,6,7,8-hexahydro-4H-cyclopenta [5,6] pyrido [2,3-d] pyrimidin-4-one (Compound II) were synthesized and characterized by IR, 1 H-NMR, 13 C-NMR and mass spectroscopy. The inhibition behavior of these derivatives for the corrosion of API 5L X52 carbon steel in 5% sulfamic acid solutions were considered by various electrochemical methods such as potentiodynamic polarization (PP ), electrochemical impedance spectroscopy (EIS ) and electrochemical frequency modulation ( EFM ) techniques, theoretically by quantum chemical calculations by using DFT method and molecular dynamic simulation (MD) . PP curves presented that the PPDs act as mixed type inhibitors. By increasing PPDs compounds concentrations, the inhibition efficiency increases. The adsorption of PPDs follows Langmuir adsorption isotherm. Excellent agreement was established between the quantum chemical parameters and the experimental data. [ABSTRACT FROM AUTHOR]

• Sulfamic acid induced corrosion of zinc was invistigated. • BSA-Np were introduced as sustainable corrosion inhibitor. • BSP-Np were characterized by spectroscopic and TEM techniques. • BSP-Np gave optimum efficiency of 90% with a minimum concentration of 0.1 gL−1. • BSA-Np emerged as eco-friendly, tangible inhibitor with financial benefits. Primary step of work is to synthesis and characterize of nanoparticles of biopolymer Bovine Serum Albumin (BSA-Np). Then it is used as green inhibitior for corrosion mitigation of zinc in sulfamic acid (NH 2 SO 3 H). BSA-Np was synthesized by the microwave-assisted nanoprecipitation method and characterized by XRD, UV–Visible, FT-IR, TEM, EDX and Zeta potential measurements. Corrosion inhibition studies were performed by electrochemical techniques like potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. Conditions were established to obtain maximum inhibition efficiency by varying experimental conditions like concentration of inhibitor and temperature. Kinetic and thermodynamic parameters were computed and discussed in detail. Experimental results were fitted into appropriate adsorption isotherms and suitable mode of adorption was predicted. Adsorption of BSA-Np onto metal surfaces was complemented and substantiated by SEM, EDX and AFM measurements. More than 90% of inhibition efficiency could be achieved. Nanoparticles of biopolymer was emerged as sustainable inhibitor for corrosion mitigation of zinc. [ABSTRACT FROM AUTHOR]

Sulfamic acid is a potential material that exhibits excellent optical properties. A good quality, pure and dysprosium (Dy 3+ ) doped (2.5 and 5 mol %) Sulfamic acid (SA) single crystals were grown successfully by slow cooling method. Structural study revealed a slight change in its lattice parameters and volume, suggesting the successful incorporation of Dy 3+ in crystal system. The existence of dysprosium in the system was also confirmed. Presence of various vibrational modes was confirmed. Optical transparency was found to have a significant effect with variation in the doping concentration. Furthermore, a marked enhancement in its mechanical parameters with doping was also identified by nanoindentation technique. Etching study was also performed on the grown crystals to study the etch-pit formation and growth mechanism. Effect of doping on the thermal stability was analysed. All the results were compared and discussed in detail to get insight of the effect of doping concentration on Sulfamic acid crystal. [ABSTRACT FROM AUTHOR]

• Sulfamic acid-water clusters was calculated using DFT method. • Intermolecular interactions in Sulfamic acid-water clusters were discovered using AIM. • Sulfamic acid-water clusters was investigated by FTIR and XRD. • The introduction of water molecules into the cluster increases the intensity in the spectra FTIR and XRD. Sulfamic acid is an essential reagent in organic chemistry. It is used in the synthesis of a large number of substances used in many areas of industry. This study aims to experimentally and theoretically study the nature and energy of interactions of intermolecular bonds between sulfamic acid and water molecules using DFT, NLO, AIM, FTIR and X-ray diffraction analysis. The geometry optimization of aqueous complexes of sulfamic acid with a content of water molecules from 1 to 8 was carried out in the gas phase using the DFT B3LYP/6-311 ++ G (d,p) and PBE-D3/6-311++G(d,p) methods. Thermodynamic studies and non-linear optical (NLO) propriety of the title compound have also been investigated. The nature of the molecular interactions between water and sulfamic acid via hydrogen bonds has been investigated using the Atoms in Molecules (AIM) method. X-ray diffraction analysis confirmed that sulfamic acid is monocrystalline, while sulfamic acid/water complexes are crystalline in nature. It is shown that with an increase in the number of water molecules in aqueous complexes of sulfamic acid, there is a uniform increase in the values of Heat Capacity, Entropy, Energy of complexes and Interaction energy. It is shown that all interactions of hydrogen bonds in all SAA- (H 2 O) 1-8 complexes have binding energies in the range from -1.31 to -154.91 kJ mol−1. [Display omitted] [ABSTRACT FROM AUTHOR]

• An eco-friendly synthesis of biologically significant spirooxindoles derivatives. • Use of aqueous ethanol makes this methodology more superior to the existing one. • High to excellent yield (upto 96%) was found in shorter reaction time. • No metal catalyst is required. • The methodology requires no Coloumn chromatography to purify the products. Development of an expeditious and green protocol to access pharmaceutically relevant and diversely functionalized scaffolds, Spiro [indoline-3,7′-pyrano[3,2- c :5,6- c ']dichromene]-2,6′,8′-trione, has been accomplished based on a pseudo three-component reaction between isatins and 4-hydroxycoumarin in presence of a low-cost and eco-friendly solid sulfamic acid catalyst in aqueous ethanol (1:1, v/v) under reflux condition. The significant features of this newly developed method are metal-free one pot synthesis, use of eco-friendly and cost-effective solvent and catalyst, no column chromatography involvement for isolation of the products, high to excellent yields, reusability of reaction media and gram scale synthetic applicability. [Display omitted] [ABSTRACT FROM AUTHOR]

Chitosan is an important biologically active amino polysaccharide. Water-soluble sulfated chitosan derivatives are widely used as anticoagulant and antiviral drugs. In this study, new methods for sulfamic acid sulfation of chitosan in the presence of urea in 1,4-dioxane and in a deep eutectic solvent representing a mixture of sulfamic acid and urea have been proposed. Mathematical models of sulfation of chitosan in these systems have been built. The obtained sulfated chitosan derivatives have been investigated by Fourier-transform infrared spectroscopy, X-ray diffractometry, atomic force microscopy, gel permeation chromatography, elemental analysis, and the density functional theory. The introduction of the sulfate group into the chitosan molecule was proven by infrared spectroscopy. When using the sulfamic acid/urea mixture, side reactions of carbamation of chitosan have been observed. It has been established from the atomic force microscopy data that the sulfated chitosan film surface consists of spherical particles partially agglomerated with each other. According to the gel permeation chromatography data, sulfated chitosan obtained in different systems, but under the same conditions (temperature and time), has different molecular weight distributions. The molecular weight distribution curve of the sulfated chitosan obtained in the sulfamic acid‒urea‒1,4-dioxane system is significantly shifted to the high-molecular region (Mw ~ 36.6 kDa), while the sulfated chitosan obtained in the sulfamic acid/urea deep eutectic solvent (Mw ~ 27.2 kDa). The density functional theory calculation of chitosan sulfates in the B3LYP/6-31G(d, p) basis set have been made. [ABSTRACT FROM AUTHOR]

In order to further explore the role of Charge-assisted hydrogen bonds (CAHBs) recognition in the formation of tetrahydroberberine (THB) pharmaceutical salt/cocrystal, based on the analysis of the molecular interactions in forming unit pharmaceutical salts/cocrystal of THB and sulfophenyl acids, we speculate that hydroxyl group of sulfamic acid (SA) may cocrystallize with N atom on the quinoline ring of THB via CAHBs. Consequently, an unreported pharmaceutical salt (C 20 H 22 NO 4 ·NH 2 SO 3 , THB-SA) of the THB was designed and synthesized. The THB-SA was characterized by single crystal X-ray diffraction, XRPD and TG methods. As expected, structure analysis of the THB-SA revealed that the THB molecule binds to the SA molecule precisely through CAHBs (N+-H···O−) between the N atom on the quinoline ring and sulfonic acid group of SA in asymmetric unit of THB-SA. This successfully implemented work implies that in the preparation of THB pharmaceutical salts/cocrystals, cocrystal formers (CCFs) that can form CAHBs with THB should be selected, which will provide a facilitate way to prepare THB pharmaceutical salts/cocrystals. Image 1 • The successful preparation of THB-SA pharmaceutical salt has been verified that the formation mechanism of CAHBs in tetrahydroberberine and sulfamic acid is basically consistent with the formation mechanism of CAHBs in tetrahydroberberine and organic acids. [ABSTRACT FROM AUTHOR]

The process of sulfation of starch with sulfamic acid in the presence of urea was studied. The sulfur content of starch sulfate increases with increasing sulfation temperature from 70 to 100 °C. To obtain starch sulfates with a high sulfur content (about 10 wt%), It is advisable to carry out the sulfation process at a temperature of 100 °C for 120 min. Mathematical modeling of the process of sulfation of starch with sulfamic acid in the presence of urea was carried out. The introduction of a sulfate group in the structure of starch is confirmed by FTIR spectroscopy. In the FTIR spectra of sulfated starch, in contrast to the original starch, there are absorption bands at 1255 cm−1, 808-817 cm−1 and 859-867 cm−1, corresponding to sulfate groups. Sulfation of starch with a complex of sulfamic acid - urea can improve the environmental safety and efficiency of the process in comparison with the known methods of sulfation. Initial starch and sulfated starch were analyzed by gel permeation chromatography. The initial starch was shown to have a main peak with Mn 139 kDa and Mw 382 kDa, and sulfated starch has a peak in the chromatogram relating to Mn 44 kDa and Mw 60 kDa. Besides, the quantum chemical calculations of the starch and sulfated starches (in dimer forms) formed when different number of hydroxyl groups in starch were replaced with sulfate groups were performed using the DFT/B3LYP method with 6-31+G (d, p) basis set in the ground state. Firstly, these molecules were optimized. Then, from the optimized geometry of the starch and sulfated starches, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP) surfaces, bond parameters, chemical reactivity descriptors such as chemical potential, electron affinity, electronegativity, ionization energy, electrophilicity index and chemical hardness have been calculated theoretically. In addition, spectroscopic analyzes of starch and sulfated starches such as FTIR and 1H NMR were theoretically performed using the same method and compared with each other. • Method for producing starch sulfates is shown to be more environmentally friendly in comparison with the known methods. • Mathematical modeling of the process of starch sulfation by sulfamic acid-urea complex was carried out. • Sulfated starch has a peak in the chromatogram relating to Mn 44 kDa and Mw 60 kDa. • Electronic properties, molecular structure, vibrational frequencies of the initial and sulfated starches were calculated. [ABSTRACT FROM AUTHOR]