MDPI - Publisher of Open Access Journals

6 pages, 790 KiB

Open AccessShort Note

6-Amino-4-phenylpyrrolo[2,3-c][1,2,6]thiadiazine-5-carbonitrile

by Andreas S. Kalogirou, Andreas Kourtellaris and Panayiotis A. Koutentis

Molbank 2025, 2025(3), M2043; https://doi.org/10.3390/M2043 - 28 Jul 2025

Viewed by 251

The reaction of 2-(3-chloro-5-phenyl-4H-1,2,6-thiadiazin-4-ylidene)malononitrile with ammonia in anhydrous THF, at ca. 20 °C, for 24 h, gave 6-amino-4-phenylpyrrolo[2,3-c][1,2,6]thiadiazine-5-carbonitrile in 95% yield. The product was characterized by ¹H and ¹³C NMR, SC-XRD, MALDI-TOF mass spectrometry, FTIR, and UV-vis [...] Read more.

The reaction of 2-(3-chloro-5-phenyl-4H-1,2,6-thiadiazin-4-ylidene)malononitrile with ammonia in anhydrous THF, at ca. 20 °C, for 24 h, gave 6-amino-4-phenylpyrrolo[2,3-c][1,2,6]thiadiazine-5-carbonitrile in 95% yield. The product was characterized by ¹H and ¹³C NMR, SC-XRD, MALDI-TOF mass spectrometry, FTIR, and UV-vis spectroscopy. Intermolecular hydrogen bonding interactions were observed in the solid state between the C≡N and N-H groups of adjacent molecules. Full article

► Show Figures

Figure 1

7 pages, 636 KiB

Open AccessShort Note

Benzyl-N-[4-(2-hydroxyethyl)-1,3-thiazol-2-yl]carbamate

by Lucrezia Spinelli, Matteo Mori and Laura Fumagalli

Molbank 2025, 2025(3), M2040; https://doi.org/10.3390/M2040 - 21 Jul 2025

Viewed by 537

Abstract

Heterocycles—cyclic compounds containing at least one non-carbon heteroatom (e.g., N, O, S)—are fundamental in medicinal chemistry due to their influence on a drug’s physicochemical and biological properties. They improve solubility, bioavailability, and facilitate molecular recognition through their electronic and hydrogen-bonding features. These properties [...] Read more.

Heterocycles—cyclic compounds containing at least one non-carbon heteroatom (e.g., N, O, S)—are fundamental in medicinal chemistry due to their influence on a drug’s physicochemical and biological properties. They improve solubility, bioavailability, and facilitate molecular recognition through their electronic and hydrogen-bonding features. These properties make them indispensable in drug design. This study focuses on the synthesis of a key heterocyclic intermediate: benzyl-N-[4-(2-hydroxyethyl)-1,3-thiazol-2-yl]carbamate. This molecule incorporates a thiazole ring, known for its rigidity and electronic properties, that enhances target interactions. The 2-position bears a Cbz-protected amine, enabling orthogonal deprotection, while the 4-position features a hydroxyethyl side chain, providing a handle for further chemical modifications via nucleophilic substitution. Herein, we report the successful synthesis of this intermediate along with its full ¹H and ¹³C NMR spectra, melting point, and crystal structure, confirming its identity and purity. Full article

► Show Figures

Figure 1

16 pages, 1696 KiB

Open AccessCommunication

Synthesis and Characterization of Amide-Based Cyclotriphosphazene Derivatives with Alkoxy Terminal Groups

by Khairunnisa Abdul Rahim and Zuhair Jamain

Molbank 2025, 2025(3), M2039; https://doi.org/10.3390/M2039 - 21 Jul 2025

Viewed by 274

Abstract

A series of new amide-based cyclotriphosphazene molecules consisting of different terminal groups (heptyl, decyl, and tetradecyl) at the periphery was successfully synthesized and characterized. The reaction began with the alkylation of methyl-4-hydroxybenzoate with 1-bromoheptane, 1-bromodecane, and 1-bromotetradecane, which was followed by reduction with [...] Read more.

A series of new amide-based cyclotriphosphazene molecules consisting of different terminal groups (heptyl, decyl, and tetradecyl) at the periphery was successfully synthesized and characterized. The reaction began with the alkylation of methyl-4-hydroxybenzoate with 1-bromoheptane, 1-bromodecane, and 1-bromotetradecane, which was followed by reduction with potassium hydroxide to form a series of benzoic acid intermediates (1a–c). These intermediates underwent a reaction with thionyl chloride, followed by a reaction with 4-nitroaniline and triethylamine, to form para-substituted amides (2a–c). Further reduction of intermediates 2a–c with sodium sulfide hydrate produced the anilines 3a–c. Another reaction of hexachlorocyclotriphosphazene (HCCP) with methyl-4-hydroxybenzoate yielded intermediate 4, which was then reduced with sodium hydroxide to form intermediate 5. Finally, chlorination of intermediate 5 with thionyl chloride, followed by a reaction with the aniline derivatives (3a–c), formed the hexasubstituted cyclotriphosphazene compounds 6a–c, with two amide linkages. The structures of these compounds were confirmed using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and CHN elemental analysis. Full article

► Show Figures

Figure 1

4 pages, 652 KiB

Open AccessShort Note

3-Methyl-2-((methylthio)methyl)but-2-enal

by Huaxuan Zhang and Xingang Xie

Molbank 2025, 2025(3), M2037; https://doi.org/10.3390/M2037 - 16 Jul 2025

Viewed by 237

Abstract

During the Swern oxidation of 3-methylbut-3-en-1-ol, an unexpected C-C bond formation product, 3-methyl-2-(methylthio)but-2-enal, was obtained. Its structure was characterized using ¹H-NMR, ¹³C-NMR, and HRMS. Based on the classical Swern oxidation mechanism and the unique structural features of the substrate, we propose [...] Read more.

During the Swern oxidation of 3-methylbut-3-en-1-ol, an unexpected C-C bond formation product, 3-methyl-2-(methylthio)but-2-enal, was obtained. Its structure was characterized using ¹H-NMR, ¹³C-NMR, and HRMS. Based on the classical Swern oxidation mechanism and the unique structural features of the substrate, we propose a plausible reaction pathway. This discovery not only provides insights into the selection of oxidation conditions for 1, 1-disubstituted homoallylic alcohols with analogous structures but also offers a viable synthetic route for the preparation of compounds containing the 3-methyl-2-(methylthio)but-2-enal motif. Full article

► Show Figures

Figure 1

7 pages, 806 KiB

Open AccessCommunication

Two Cocrystals of Phenazine with Different Phenylboronic Acids

by Stijn Germonpré, Subhrajyoti Bhandary and Kristof Van Hecke

Molbank 2025, 2025(3), M2036; https://doi.org/10.3390/M2036 - 14 Jul 2025

Viewed by 405

Abstract

Boronic acids are an important class of molecules diversely used in organic synthesis, catalysis, medicinal chemistry, and for the design of functional materials. Particularly, aryl boronic acids in the solid state are known to exhibit pharmaceutical and photoluminescent properties for antimicrobial, sensing, and [...] Read more.

Boronic acids are an important class of molecules diversely used in organic synthesis, catalysis, medicinal chemistry, and for the design of functional materials. Particularly, aryl boronic acids in the solid state are known to exhibit pharmaceutical and photoluminescent properties for antimicrobial, sensing, and drug delivery applications. Furthermore, the phenazine molecule is known for its diverse pharmacological properties, including antibiotic activity. In the case of molecular crystalline solids, it is well established that understanding noncovalent interactions remains key to designing or engineering their functional properties. While both aryl boronic acids and phenazine molecules individually represent an important class of compounds, their co-assembly in the crystalline state is of interest within the context of supramolecular chemistry and crystal engineering. Herein, we report the supramolecular features of two newly synthesized cocrystals, which are composed of para-F/CF₃-substituted phenylboronic acids, respectively, and phenazine, as demonstrated by structure analysis by single-crystal X-ray diffraction. Full article

► Show Figures

Figure 1

9 pages, 1055 KiB

Open AccessShort Note

A Pyrene-Anchored Nickel N-Heterocyclic Carbene–Isoquinoline Complex Promotes CO₂ Reduction

by Xue Chen, Li-Li Yu, Shu-Ying Chen, Tong Wang and Quan Zhou

Molbank 2025, 2025(3), M2035; https://doi.org/10.3390/M2035 - 8 Jul 2025

Viewed by 360

Abstract

In this study, on the basis of a previous report, a pyrene-anchored nickel complex was designed and synthesized via five steps. The NMR spectra of the synthesized complex were found to exhibit significant proton and carbon chemical shift anisotropy. Cyclic voltammetry spectra showed [...] Read more.

In this study, on the basis of a previous report, a pyrene-anchored nickel complex was designed and synthesized via five steps. The NMR spectra of the synthesized complex were found to exhibit significant proton and carbon chemical shift anisotropy. Cyclic voltammetry spectra showed that the introduction of pyrene slightly influenced the onset potential of CO₂ reduction. Lastly, controlled-potential electrolysis experiments disclosed that a pyrene-anchored nickel carbene–isoquinoline (Ni−2) complex selectively converted CO₂ into CH₄ with a TON value of 2.3 h⁻¹. Full article

(This article belongs to the Topic Heterocyclic Carbene Catalysis)

► Show Figures

Figure 1

5 pages, 302 KiB

Open AccessShort Note

(5R,7R,11bR)-9-(di(1H-Indol-3-yl)methyl)-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-5-yl Acetate

by Jessica A. Perez-Rangel, Gabriela Servín-García, Atilano Gutiérrez-Carrillo, Alejandro Islas-Jácome, Luis Chacón-García, Rosa E. del Río and Carlos J. Cortés-García

Molbank 2025, 2025(3), M2034; https://doi.org/10.3390/M2034 - 7 Jul 2025

Viewed by 349

Abstract

The semi-synthesis of the (5R,7R,11bR)-9-(di(1H-indol-3-yl)methyl)-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-5-yl acetate was performed via a pseudo-multicomponent reaction involving a double Friedel–Crafts alkylation between the natural product-derived aldehyde 6β-acetoxyvouacapane and the corresponding indole. The transformation was carried [...] Read more.

The semi-synthesis of the (5R,7R,11bR)-9-(di(1H-indol-3-yl)methyl)-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-5-yl acetate was performed via a pseudo-multicomponent reaction involving a double Friedel–Crafts alkylation between the natural product-derived aldehyde 6β-acetoxyvouacapane and the corresponding indole. The transformation was carried out under solvent-free mechanochemical conditions using mortar and pestle grinding, with ZnCl₂ as the catalyst. Structural elucidation of the target compound was accomplished using 1D and 2D NMR spectroscopy (¹H, ¹³C, COSY, HSQC, and HMBC), FT-IR, and high-resolution mass spectrometry (HRMS). Full article

► Show Figures

Graphical abstract

9 pages, 2968 KiB

Open AccessShort Note

Diethyl 3-(4-Bromobenzoyl)-7-(4-pyridyl)indolizine-1,2-dicarboxylate

by Mihaela Cristea, Mihai Răducă, Maria Gdaniec, Sergiu Shova, Nicoleta Doriana Banu and Florea Dumitrascu

Molbank 2025, 2025(3), M2032; https://doi.org/10.3390/M2032 - 7 Jul 2025

Viewed by 405

Abstract

The title compound, C₂₆H₂₁BrN₂O₅ (Compound 4), was obtained via our previously described procedure with modifications, i.e., via a facile one-pot three component reaction starting from commercially available materials. Compound 4 was crystallized from nitromethane. It [...] Read more.

The title compound, C₂₆H₂₁BrN₂O₅ (Compound 4), was obtained via our previously described procedure with modifications, i.e., via a facile one-pot three component reaction starting from commercially available materials. Compound 4 was crystallized from nitromethane. It crystalized in a triclinic crystal system, in the P-

\bar{1}

space group. The crystal structure of 4 is described herein. Hirsfeld surface analysis, generated by the Crystal Explorer 21 software, was used to visualize the intermolecular close contacts in the title compound. The electrostatic, dispersion, and total energies in the crystal structure were calculated using the same program. Full article

► Show Figures

Graphical abstract

5 pages, 335 KiB

Open AccessShort Note

2-(2-(Benzylamino)-2-Oxoethyl)-1-Methyl-1H-Pyrrole-3-Carboxylic Acid

by Monika Fryc, Beata Gryzło, Pravin Kumar and Agnieszka Zagórska

Molbank 2025, 2025(3), M2026; https://doi.org/10.3390/M2026 - 20 Jun 2025

Viewed by 505

Abstract

Here, 2-(2-(Benzylamino)-2-oxoethyl)-1-methyl-1H-pyrrole-3-carboxylic acid was efficiently synthesised in good yield via an amide coupling reaction between 2-carboxymethyl-1-methyl-1H-pyrrole-3-carboxylic acid and benzylamine, employing TBTU as the coupling reagent and DIPEA as the base. The reaction was carried out in dichloromethane at room [...] Read more.

Here, 2-(2-(Benzylamino)-2-oxoethyl)-1-methyl-1H-pyrrole-3-carboxylic acid was efficiently synthesised in good yield via an amide coupling reaction between 2-carboxymethyl-1-methyl-1H-pyrrole-3-carboxylic acid and benzylamine, employing TBTU as the coupling reagent and DIPEA as the base. The reaction was carried out in dichloromethane at room temperature. The compound was characterised by melting point determination, ¹H and ¹³C NMR, IR spectroscopy, and mass spectrometry. The combined analytical data confirm the target molecule’s successful synthesis and structural integrity. Full article

► Show Figures

Figure 1

8 pages, 882 KiB

Open AccessShort Note

bis(2-Phenylpyridinato)-[4,4′-bis(iodoethynyl)-2,2′-bipyridine]-iridium(III) Hexafluorophosphate

by Patrick Endres, Nishi Singh, Andreas Winter, Helmar Görls and Ulrich S. Schubert

Molbank 2025, 2025(2), M2024; https://doi.org/10.3390/M2024 - 18 Jun 2025

Viewed by 432

Abstract

This work presents the synthesis and structural characterization of a novel type of biscyclometalated Ir(III) complex, which is equipped with two iodoethynyl moieties on its 2,2′-bipyridine (bpy) ligand. Iodoethynyl moieties represent prominent donor systems for the formation of supramolecular structures via halogen bonding [...] Read more.

This work presents the synthesis and structural characterization of a novel type of biscyclometalated Ir(III) complex, which is equipped with two iodoethynyl moieties on its 2,2′-bipyridine (bpy) ligand. Iodoethynyl moieties represent prominent donor systems for the formation of supramolecular structures via halogen bonding (X-bonding). The synthesis of bis(2-phenylpyridinato)-[4,4′-bis(iodoethynyl)-2,2′-bipyridine]iridium(III) hexafluorophosphate, (2)(PF₆), is straightforward and involves post-complexation iodination, thus expanding the already rich toolbox for performing “chemistry on the complex”. The formation of the iodoethynyl moieties was unequivocally proven by ¹H-NMR spectroscopy, ESI-TOF mass spectrometry, and single-crystal XRD analysis. Full article

► Show Figures

Figure 1

4 pages, 560 KiB

Open AccessShort Note

(Z)-2-(Bromomethyl)-3-(hydroxymethylene)-7-methoxy-5-methyl-2-(tribromomethyl)-4-chromanone

by Chein-Chung Lee and Yen-Ku Wu

Molbank 2025, 2025(2), M2023; https://doi.org/10.3390/M2023 - 16 Jun 2025

Viewed by 467

Abstract

An attempt to achieve the deprotonative bromination of a 2-methyl-3-formyl-chromenone with tetrabromomethane led to an unexpected bromo-tribromomethylation product. We report the synthesis and characterization of the title compound. Full article

► Show Figures

Figure 1

9 pages, 2176 KiB

Open AccessShort Note

4-Methyl-N-(1-benzyl)-N’-(1-benzylidene)benzenesulfonohydrazide

by Leticia Almazán-Sánchez, Marco A. García-Eleno, Diego Martínez-Otero and Erick Cuevas-Yañez

Molbank 2025, 2025(2), M2022; https://doi.org/10.3390/M2022 - 13 Jun 2025

Viewed by 376

Abstract

4-Methyl-N-(1-benzyl)-N’-(1-benzylidene)benzenesulfonohydrazide is formed through a direct, solventless reaction between benzaldehyde tosylhydrazone and potassium carbonate, which is carried out using an eco-friendly grinding method. The NMR spectra of the compound are here described. The structure was unequivocally determined by X-ray [...] Read more.

4-Methyl-N-(1-benzyl)-N’-(1-benzylidene)benzenesulfonohydrazide is formed through a direct, solventless reaction between benzaldehyde tosylhydrazone and potassium carbonate, which is carried out using an eco-friendly grinding method. The NMR spectra of the compound are here described. The structure was unequivocally determined by X-ray analysis. As suggested by Hirshfeld surface analysis, the predominant intermolecular H-O interactions in this molecule are involved in crystal packing. Full article

► Show Figures

Figure 1

6 pages, 686 KiB

Open AccessCommunication

A Neutral Heteroleptic Cu(I) Complex with Diimine and Diphosphine Ligands

by Xiaojuan Sun, Ruilong Sheng, Marijana Petkovic, Jolanta Jaśkowska and Zhiqiang Wang

Molbank 2025, 2025(2), M2019; https://doi.org/10.3390/M2019 - 6 Jun 2025

Viewed by 755

Abstract

Developing organic luminescent materials with the advantages of low cost, high thermal stability, and strong emission performance is incredibly desirable. In this work, we synthesized a new neutral heteroleptic Cu(I) complex characterized by single-crystal X-ray diffraction, FT-IR, NMR, and MALDI-TOF-MS. The neutral heteroleptic [...] Read more.

Developing organic luminescent materials with the advantages of low cost, high thermal stability, and strong emission performance is incredibly desirable. In this work, we synthesized a new neutral heteroleptic Cu(I) complex characterized by single-crystal X-ray diffraction, FT-IR, NMR, and MALDI-TOF-MS. The neutral heteroleptic Cu(I) complex has a typical distorted tetrahedral configuration, and the complex molecules are connected into 1D chains via C-H···π interactions in crystal. Full article

► Show Figures

Graphical abstract

8 pages, 1150 KiB

Open AccessCommunication

Structural Characterization of 7-Chloro-4-(4-methyl-1-piperazinyl)quinoline Monohydrate

by Silvia Rizzato and Francesco Marinoni

Molbank 2025, 2025(2), M2016; https://doi.org/10.3390/M2016 - 2 Jun 2025

Viewed by 840

Abstract

The crystal structure of the hydrated form of 7-chloro-4-(4-methyl-1-piperazinyl)quinoline (BPIP) was determined by single-crystal X-ray diffraction analysis. This study revealed a one-dimensional supramolecular network stabilized by hydrogen bonding interactions between BPIP and water molecules. This compound represents one-half of a piperaquine [...] Read more.

The crystal structure of the hydrated form of 7-chloro-4-(4-methyl-1-piperazinyl)quinoline (BPIP) was determined by single-crystal X-ray diffraction analysis. This study revealed a one-dimensional supramolecular network stabilized by hydrogen bonding interactions between BPIP and water molecules. This compound represents one-half of a piperaquine molecule, a member of the 4-aminoquinoline class of antimalarial treatments, currently employed as a partner agent in modern combination therapies. As a simplified structural analog, BPIP can serve as a critical model system for probing the intermolecular interactions, physicochemical properties, and structural behavior of the parent compound. As a result, conducting a thorough solid-state characterization of BPIP is critical for gaining insight into its physical properties and verifying the material’s identity and purity. Full article

► Show Figures

Graphical abstract

8 pages, 1277 KiB

Open AccessShort Note

trans-Dihydroxo[5,10,15,20-tetrakis(3-pyridinium)porphyrinato]tin(IV) Nitrate

by Nirmal Kumar Shee and Hee-Joon Kim

Molbank 2025, 2025(2), M2014; https://doi.org/10.3390/M2014 - 27 May 2025

Viewed by 662

Abstract

The treatment of trans-dihydroxo[5,10,15,20-tetrakis(3-pyridyl)porphyrinato]Sn(IV) or [Sn(OH)₂(TPyP)] with 1% nitric acid in a mixture of water and acetone resulted in the formation of an ionic complex 1 [Sn(OH)₂(TPy^HP)](NO₃)₄. Complex 1 was fully characterized [...] Read more.

The treatment of trans-dihydroxo[5,10,15,20-tetrakis(3-pyridyl)porphyrinato]Sn(IV) or [Sn(OH)₂(TPyP)] with 1% nitric acid in a mixture of water and acetone resulted in the formation of an ionic complex 1 [Sn(OH)₂(TPy^HP)](NO₃)₄. Complex 1 was fully characterized by ¹H NMR spectroscopy, elemental analysis, UV-vis spectroscopy, powder X-ray diffraction, fluorescence spectroscopy, FT-IR spectroscopy, and single-crystal X-ray crystallography. X-ray crystallographic analysis confirmed that each peripheral pyridyl N atom is protonated to form tetra-cationic species {Sn(OH)₂(TPy^HP)}⁴⁺ stabilized by four NO₃⁻ counter anions. Intermolecular hydrogen bonding interaction between axial hydroxo ligands leads to the formation of a 1D porphyrin array. Nitrate anions also involve hydrogen bonding interactions with axial hydroxo ligands and the peripheral pyridinium groups. Full article

► Show Figures

Figure 1

Search Results (927)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Article Types

Countries / Regions

Search Results (927)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI