Molbank

6 pages, 625 KiB

Open AccessCommunication

Three Hypoxanthine Derivatives from the Marine Cyanobacterium Okeania hirsuta

by Ryoya Kawabe, Botao Zhang, Ryuichi Watanabe, Hajime Uchida, Masayuki Satake and Hiroshi Nagai

Molbank 2025, 2025(3), M2051; https://doi.org/10.3390/M2051 - 21 Aug 2025

Abstract

Three novel hypoxanthine derivatives (1–3) were obtained from the Okinawan cyanobacterium Okeania hirsuta. The structures of these compounds were elucidated mainly based on the spectroscopic data, including 1D and 2D NMR, as well as high-resolution mass spectrometry. In [...] Read more.

Three novel hypoxanthine derivatives (1–3) were obtained from the Okinawan cyanobacterium Okeania hirsuta. The structures of these compounds were elucidated mainly based on the spectroscopic data, including 1D and 2D NMR, as well as high-resolution mass spectrometry. In particular, the amounts of obtained compounds 2 and 3 were only 200 μg and much less than 50 μg, respectively. Therefore, some carbons signals could not be observed on ¹³C NMR spectra of these compounds. However, the detailed analysis of HSQC and HMBC spectra allowed us to elucidate their structures. For NMR measurements of compound 3, it was found that using an 800 MHz NMR machine equipped with a cryogenic probe and acetic acid-d₄ as a solvent is essential. Compounds (1–3) were N-3′-carbonylbutyl group-connected hypoxanthines. Full article

(This article belongs to the Section Natural Product Chemistry)

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7 pages, 403 KiB

Open AccessCommunication

Synthesis of a New Bioconjugate Steroid Pyridinium Salt Derived from Allopregnanolone Acetate

by Hisami Rodríguez-Matsui, J. Luis Sánchez-Juárez, Vladimir Carranza-Téllez, Joel L. Terán, Jesús Sandoval-Ramirez and Alan Carrasco-Carballo

Molbank 2025, 2025(3), M2050; https://doi.org/10.3390/M2050 - 20 Aug 2025

Viewed by 108

Abstract

Because allopregnanolone and derivatives represent biologically active molecules, in this letter, we present the synthesis of a new bioconjugate steroid pyridinium salt derived from allopregnanolone in three steps. The key steps involve the formation of the hydrazone intermediate, followed by condensation with bromoacetyl [...] Read more.

Because allopregnanolone and derivatives represent biologically active molecules, in this letter, we present the synthesis of a new bioconjugate steroid pyridinium salt derived from allopregnanolone in three steps. The key steps involve the formation of the hydrazone intermediate, followed by condensation with bromoacetyl bromide and subsequent coupling with pyridine to generate the pyridinium bromide salt. The new bioconjugate steroid pyridinium salt, 4, was fully characterized by proton and carbon nuclear magnetic resonance (¹H and ¹³C NMR) spectroscopy, mass spectrometry (MS), and Fourier transform infrared spectroscopy (FTIR). ¹H-NMR analysis revealed the presence of a dynamic rotameric mixture in a 7:3 ratio of Z/E amide conformers, which were identified by a 2D NOESY experiment. Full article

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4 pages, 337 KiB

Open AccessShort Note

5-[2-(4-Chlorophenyl)-2-oxoethyl]-3-(4-hydroxyphenyl)-2-thioxo-1,3-thiazolidin-4-one

by Nazar Trotsko

Molbank 2025, 2025(3), M2049; https://doi.org/10.3390/M2049 - 20 Aug 2025

Viewed by 82

Abstract

Rhodanine derivatives, as a subtype of thiazolidin-4-ones, represent an important class of heterocyclic compound known for their broad spectrum of biological activities and practical applications. In this short note, the synthesis of a new compound, 5-[2-(4-chlorophenyl)-2-oxoethyl]-3-(4-hydroxyphenyl)-2-thioxo-1,3-thiazolidin-4-one, is described. The target molecule was synthesized [...] Read more.

Rhodanine derivatives, as a subtype of thiazolidin-4-ones, represent an important class of heterocyclic compound known for their broad spectrum of biological activities and practical applications. In this short note, the synthesis of a new compound, 5-[2-(4-chlorophenyl)-2-oxoethyl]-3-(4-hydroxyphenyl)-2-thioxo-1,3-thiazolidin-4-one, is described. The target molecule was synthesized via a thia-Michael addition followed by cyclocondensation. Its structure was confirmed by ¹H and ¹³C NMR spectroscopy and further supported by 2D NMR studies. Full article

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7 pages, 612 KiB

Open AccessShort Note

4-(1,3-Dioxoisoindolin-2-yl)butyl(2R,4aS,6aS,12bR,14aS,14bR)-10-hydroxy-2,4a,6a,9,12b,14a-hexamethyl-11-oxo-1,2,3,4,4a,5,6,6a,11,12b,13,14,14a,14b-tetradecahydropicene-2-carboxylate

by Zihan Chen, Ka Fai Leong, Carmine Coluccini and Paolo Coghi

Molbank 2025, 2025(3), M2048; https://doi.org/10.3390/M2048 - 19 Aug 2025

Viewed by 134

Abstract

In this report, we describe the synthesis of a compound derived from the natural compound celastrol, which is connected to a phthalimide moiety via an ester linkage. The compound was fully characterized by proton (¹H), carbon-13 (¹³C), heteronuclear single-quantum [...] Read more.

In this report, we describe the synthesis of a compound derived from the natural compound celastrol, which is connected to a phthalimide moiety via an ester linkage. The compound was fully characterized by proton (¹H), carbon-13 (¹³C), heteronuclear single-quantum coherence (HSQC), and distortionless enhancement by polarization transfer (DEPT) NMR. Ultraviolet–visible spectroscopy (UV-Vis), Fourier-transform infrared (FTIR), and elementary analysis were also performed. Full article

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8 pages, 1233 KiB

Open AccessShort Note

5-((3′,5′-Dibromo-[2,2′-bithiophen]-5-yl)methyl)-3-ethyl-2-thioxothiazolidin-4-one∙Br₂ (1:1)

by Enrico Podda, Simone Acca, Maria Carla Aragoni, Vito Lippolis, Anna Pintus, Massimiliano Arca and Giuseppe Sforazzini

Molbank 2025, 2025(3), M2047; https://doi.org/10.3390/M2047 - 14 Aug 2025

Viewed by 186

Abstract

The reaction of rhodanine vinyl bithiophene (BTR) with molecular dibromine (Br₂) resulted in the formation of compound 1. Single-crystal X-ray diffraction analysis revealed bromination of the terminal thiophenyl ring and the formation of a 1:1 CT “spoke” adduct between the [...] Read more.

The reaction of rhodanine vinyl bithiophene (BTR) with molecular dibromine (Br₂) resulted in the formation of compound 1. Single-crystal X-ray diffraction analysis revealed bromination of the terminal thiophenyl ring and the formation of a 1:1 CT “spoke” adduct between the rhodanine thiocarbonyl group and a neutral dibromine (Br₂) molecule. Full article

(This article belongs to the Section Structure Determination)

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6 pages, 857 KiB

Open AccessShort Note

Methyl α-d-Tagatopyranoside

by Yiming Hu, Akihiro Iyoshi, Masakazu Tanaka and Atsushi Ueda

Molbank 2025, 2025(3), M2046; https://doi.org/10.3390/M2046 - 14 Aug 2025

Viewed by 185

Abstract

d-Tagatose, classified as a rare sugar, exhibits notable biological activities, including its function as a low-calorie sweetener. The three-dimensional configuration of carbohydrates is crucial for elucidating their functional properties. Numerous studies have reported the X-ray crystallographic structures of d-tagatose and its [...] Read more.

d-Tagatose, classified as a rare sugar, exhibits notable biological activities, including its function as a low-calorie sweetener. The three-dimensional configuration of carbohydrates is crucial for elucidating their functional properties. Numerous studies have reported the X-ray crystallographic structures of d-tagatose and its derivatives bearing a free anomeric hydroxy group. However, there are no reports on the X-ray crystallographic structure of d-tagatosides featuring a glycosidic linkage at the anomeric position. In this study, we synthesized methyl α-d-tagatopyranoside from d-tagatose and successfully determined its X-ray crystallographic structure, revealing its ⁵C₂ conformation. Full article

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6 pages, 640 KiB

Open AccessShort Note

Bis(4-((E)-3,5–Diacetoxystyryl)phenyl)nonanedioate

by Claudia Sciacca, Giulia Maria Grasso, Nunzio Cardullo and Vera Muccilli

Molbank 2025, 2025(3), M2044; https://doi.org/10.3390/M2044 - 5 Aug 2025

Viewed by 231

Abstract

Resveratrol is a natural stilbene known for its wide range of biological activities, including antioxidant, anti-inflammatory, and anti-aging effects. However, its application in cosmetics and dermatology is limited by poor stability and bioavailability. Azelaic acid is a natural carboxylic acid employed in cosmetics [...] Read more.

Resveratrol is a natural stilbene known for its wide range of biological activities, including antioxidant, anti-inflammatory, and anti-aging effects. However, its application in cosmetics and dermatology is limited by poor stability and bioavailability. Azelaic acid is a natural carboxylic acid employed in cosmetics for its tyrosinase inhibition activity and for cutaneous hyperpigmentation disorders. In this work, we report a concise chemoenzymatic procedure for the synthesis of a novel hybrid molecule combining acetylated resveratrol and azelaic acid. This methodology offers a valuable route for the development of new bioactive compounds for potential cosmetic and dermatological applications. Full article

(This article belongs to the Section Organic Synthesis and Biosynthesis)

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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 297

Abstract

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

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11 pages, 2689 KiB

Open AccessCommunication

Synthesis and Structural Characterization of Manganese(I) Complexes Ligated by 2-Azabutadienes (ArS)₂C=C(H)-N=CPh₂

by Rodolphe Kinghat, Abderrahim Khatyr, Michael Knorr, Yoann Rousselin and Marek M. Kubicki

Molbank 2025, 2025(3), M2042; https://doi.org/10.3390/M2042 - 28 Jul 2025

Viewed by 238

Abstract

The thioether-functionalized 2-azabutadienes (ArS)₂C=C(H)-N=CPh₂ (L1 Ar = Ph, L2 Ar = p-Tol) ligate to [Mn(CO)₅Br] to form the octahedral five-membered S, N-chelate complexes fac-[MnBr(CO)₃{(ArS)₂C=C(H)-N=CPh₂] (1 Ar [...] Read more.

The thioether-functionalized 2-azabutadienes (ArS)₂C=C(H)-N=CPh₂ (L1 Ar = Ph, L2 Ar = p-Tol) ligate to [Mn(CO)₅Br] to form the octahedral five-membered S, N-chelate complexes fac-[MnBr(CO)₃{(ArS)₂C=C(H)-N=CPh₂] (1 Ar = Ph; 2 Ar = p-Tol), whose crystal structures have been solved by X-ray diffraction. Complex 1 crystallizes in the non-centrosymmetric orthorhombic space group P2₁2₁2₁, whereas 2 crystallizes in the triclinic space group P

\bar{1}

. The secondary interactions occurring in the packing have also been assessed by an Atoms in Molecules (AIM) topological analysis. Full article

(This article belongs to the Section Structure Determination)

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7 pages, 421 KiB

Open AccessShort Note

1,3,4,5-Tetra-O-benzoyl-α-d-tagatopyranose

by Yiming Hu, Akihiro Iyoshi, Yui Makura, Masakazu Tanaka and Atsushi Ueda

Molbank 2025, 2025(3), M2041; https://doi.org/10.3390/M2041 - 22 Jul 2025

Cited by 1 | Viewed by 309

Abstract

d-Tagatose, a rare sugar, is recognized as a low-calorie sweetener, used in daily life. Although d-tagatose exhibits intriguing biological activities, the synthesis of its derivatives has rarely been reported. In this study, we developed a method for synthesizing 1,3,4,5-tetra-O-benzoyl-α- [...] Read more.

d-Tagatose, a rare sugar, is recognized as a low-calorie sweetener, used in daily life. Although d-tagatose exhibits intriguing biological activities, the synthesis of its derivatives has rarely been reported. In this study, we developed a method for synthesizing 1,3,4,5-tetra-O-benzoyl-α-d-tagatopyranose through the regioselective benzoylation of d-tagatose in a single step, achieving an 88% yield on a gram scale. Additionally, 1,2,3,4,5-penta-O-benzoyl-α-d-tagatopyranose and 1,2,3,4,6-penta-O-benzoyl-α-d-tagatofuranose were synthesized in 50% yield as a 7:1 mixture. The structures of the three new benzoylated d-tagatose derivatives were confirmed by ¹H, ¹³C NMR, 2D NMR, FT-IR, and HRMS analyses. Full article

(This article belongs to the Section Organic Synthesis and Biosynthesis)

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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 714

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

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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 380

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

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8 pages, 641 KiB

Open AccessCommunication

Synthesis of 2-(2-((5″-(4-Cyanophenyl)-3,4′,4″-trioctyl[2,2′:5′,2″-terthiophen]-5-yl)methylene)-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile

by Alexia M. Frîncu, Lidia Căta, David Bălăceanu, Ion Grosu, Andreea P. Crișan and Anamaria Terec

Molbank 2025, 2025(3), M2038; https://doi.org/10.3390/M2038 - 18 Jul 2025

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Abstract

A new π-conjugated acceptor–donor–acceptor small molecule, designed for applications in organic solar cells, containing a terthiophene core and indandione- and benzonitrile-based electron-withdrawing units, was synthesized via a multi-step process involving Suzuki–Miyaura cross-coupling and Knoevenagel condensation reactions. The structure was confirmed by NMR spectroscopy, [...] Read more.

A new π-conjugated acceptor–donor–acceptor small molecule, designed for applications in organic solar cells, containing a terthiophene core and indandione- and benzonitrile-based electron-withdrawing units, was synthesized via a multi-step process involving Suzuki–Miyaura cross-coupling and Knoevenagel condensation reactions. The structure was confirmed by NMR spectroscopy, HRMS, and its optoelectronic properties were evaluated by UV–vis spectroscopy and cyclic voltammetry. Full article

(This article belongs to the Section Organic Synthesis and Biosynthesis)

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Graphical abstract

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 290

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

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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 480

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

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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 396

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)

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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 377

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

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Graphical abstract

7 pages, 1961 KiB

Open AccessShort Note

3′H-Spiro[dibenzo[c,h]xanthene-7,1′-isobenzofuran]-3′-one

by Brian A. Chalmers, David B. Cordes, Aidan P. McKay, Iain L. J. Patterson, Nadiia Vladymyrova and Iain A. Smellie

Molbank 2025, 2025(3), M2033; https://doi.org/10.3390/M2033 - 7 Jul 2025

Viewed by 307

Abstract

Target compound 3′H-spiro[dibenzo[c,h]xanthene-7,1′-isobenzofuran]-3′-one (1) has long been known to be a by-product obtained from the preparation of naphtholphthalein. The structure of compound 1 was elucidated in the early 20th century; however, this compound has not [...] Read more.

Target compound 3′H-spiro[dibenzo[c,h]xanthene-7,1′-isobenzofuran]-3′-one (1) has long been known to be a by-product obtained from the preparation of naphtholphthalein. The structure of compound 1 was elucidated in the early 20th century; however, this compound has not previously been fully characterized using modern techniques. In this report, ¹H NMR and ¹³C NMR spectra are provided. X-ray crystallography is also used to characterize the title compound for the first time. Full article

(This article belongs to the Section Structure Determination)

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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 441

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

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Graphical abstract

10 pages, 1171 KiB

Open AccessShort Note

N,N,N′-Tris(trimethylsilyl)-2-pyridinecarboximidamide

by Mukaila A. Ibrahim, Kathryn E. Preuss and René T. Boeré

Molbank 2025, 2025(3), M2031; https://doi.org/10.3390/M2031 - 3 Jul 2025

Viewed by 388

Abstract

N,N,N′-tris(trimethylsilyl)-carboximidamides are effective reagents in synthetic chemistry in reactions with both non-metal and metal halides, because the side product is the mild and volatile ClSi(CH₃)₃ rather than corrosive HCl. The title compound inserts the 2-pyridylamidinate [...] Read more.

N,N,N′-tris(trimethylsilyl)-carboximidamides are effective reagents in synthetic chemistry in reactions with both non-metal and metal halides, because the side product is the mild and volatile ClSi(CH₃)₃ rather than corrosive HCl. The title compound inserts the 2-pyridylamidinate fragment into several non-metal systems, including custom chelating radical ligands. The single-crystal X-ray diffraction structure was determined and modeled by Hirshfeld atom refinement using custom aspherical atomic scattering factors. Excellent data quality led to a model with enhanced precision of all interatomic distances and free refinement of H-atom positions and anisotropic displacement ellipsoids. This structure model is compared to the four previously published analogous structures. Full article

(This article belongs to the Section Structure Determination)

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4 pages, 265 KiB

Open AccessShort Note

[1,2,5]Thiadiazolo[3,4-b]pyrazine-5,6(4H,7H)-dione

by Lidia S. Konstantinova, Natalia V. Obruchnikova and Oleg A. Rakitin

Molbank 2025, 2025(3), M2030; https://doi.org/10.3390/M2030 - 1 Jul 2025

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Abstract

Fused 1,2,5-chalcogenadiazoles are often used as biologically active compounds and organic optovoltaic materials. [1,2,5]Thiadiazolo[3,4-b]pyrazines are much less studied due to difficulties in their preparation. In this communication, [1,2,5]thiadiazolo[3,4-b]pyrazine-5,6(4H,7H)-dione, a key precursor for the synthesis of [...] Read more.

Fused 1,2,5-chalcogenadiazoles are often used as biologically active compounds and organic optovoltaic materials. [1,2,5]Thiadiazolo[3,4-b]pyrazines are much less studied due to difficulties in their preparation. In this communication, [1,2,5]thiadiazolo[3,4-b]pyrazine-5,6(4H,7H)-dione, a key precursor for the synthesis of 5,6-dihalo-[1,2,5]thiadiazolo[3,4-b]pyrazines, was prepared via condensation of 1,2,5-thiadiazole-3,4-diamine with oxalic acid or oxalyl chloride. The structure of the newly synthesized compound was established by elemental analysis, high-resolution mass spectrometry, ¹H and ¹³C NMR, IR spectroscopy, and mass spectrometry. Full article

(This article belongs to the Collection Heterocycle Reactions)

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10 pages, 1743 KiB

Open AccessShort Note

4-(4-Formyl-3,5-dimethoxyphenoxy)butyric Acid (BAL)

by Alex Lovstedt, Tracy R. Thompson and George Barany

Molbank 2025, 2025(3), M2029; https://doi.org/10.3390/M2029 - 26 Jun 2025

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Abstract

The title compound, 4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid (BAL), is an important “handle” for solid-phase synthesis of peptides and related compounds. Reported here is an X-ray single crystal structural analysis of BAL. The molecule is almost entirely flat, and the crystal is held together by π-stacking [...] Read more.

The title compound, 4-(4-formyl-3,5-dimethoxyphenoxy)butyric acid (BAL), is an important “handle” for solid-phase synthesis of peptides and related compounds. Reported here is an X-ray single crystal structural analysis of BAL. The molecule is almost entirely flat, and the crystal is held together by π-stacking and hydrogen bonding. Full article

(This article belongs to the Section Structure Determination)

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7 pages, 1118 KiB

Open AccessShort Note

4-([1,1′:3′,1′′-terphenyl]-2′-yloxy)-5-chlorophthalonitrile

by Dmitry Erzunov, Vyacheslav Baklagin, Igor Abramov, Vladimir Maizlish, Roman Rumyantsev and Arthur Vashurin

Molbank 2025, 2025(3), M2028; https://doi.org/10.3390/M2028 - 24 Jun 2025

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Abstract

The study focuses on the synthesis and detailed crystal structure analysis of 4-([1,1′:3′,1′′-terphenyl]-2′-yloxy)-5-chlorophthalonitrile. Using X-ray diffraction methods, the authors achieved the precise refinement of the atomic arrangement, revealing the specific spatial organization of molecules within the crystal lattice. The manuscript thoroughly discusses the [...] Read more.

The study focuses on the synthesis and detailed crystal structure analysis of 4-([1,1′:3′,1′′-terphenyl]-2′-yloxy)-5-chlorophthalonitrile. Using X-ray diffraction methods, the authors achieved the precise refinement of the atomic arrangement, revealing the specific spatial organization of molecules within the crystal lattice. The manuscript thoroughly discusses the key intermolecular interactions—such as hydrogen bonding and π-π stacking—that govern the crystal packing. These interactions play a crucial role in stabilizing the structure and have a direct impact on the material’s physical and chemical properties, including its thermal stability and optical characteristics. Full article

(This article belongs to the Section Structure Determination)

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10 pages, 4166 KiB

Open AccessCommunication

The Absolute Configuration Determination of Patagonic Acid

by Eva E. Soto-Guzmán, Hilda J. Pagaza-Ibarra, Antonio J. Oliveros-Ortiz, Gabriela Rodríguez-García, Yliana López, Brenda Y. Bedolla-García, Carlos M. Cerda-García-Rojas, Christine Thomassigny, Mario A. Gómez-Hurtado, Armando Talavera-Alemán and Rosa E. del Río

Molbank 2025, 2025(3), M2027; https://doi.org/10.3390/M2027 - 23 Jun 2025

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Abstract

(−)-Patagonic acid (1) is a clerodane diterpene isolated from several plants from the Alismataceae, Asteraceae, Euphorbiaceae, Fabaceae, Lamiaceae, Salicaceae, Sapindaceae, and Velloziaceae families, and its biological potential as an inhibitor of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) and as an anti-inflammatory compound [...] Read more.

(−)-Patagonic acid (1) is a clerodane diterpene isolated from several plants from the Alismataceae, Asteraceae, Euphorbiaceae, Fabaceae, Lamiaceae, Salicaceae, Sapindaceae, and Velloziaceae families, and its biological potential as an inhibitor of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) and as an anti-inflammatory compound has been described. Furthermore, the enantiomer (+)-1 is also described in Fabaceae and Verbenaceae. A lack of formal studies about the absolute configuration (AC) determination of 1 is emphasized. Thus, the present manuscript describes the AC determination of patagonic acid (1). The chemical correlation of (−)-1 from (−)-hardwickiic acid (2) was achieved by a simplistic oxidative process. The specific rotation value and electronic circular dichroism (ECD) analysis allowed for the AC determination of (−)-1 as (5R,8R,9S,10R)-(−)-patagonic acid. ECD revealed a positive exciton chirality (EC) phenomenon in both (−)-1 and (−)-2, which is directly associated with their configuration and conformational preferences, which were assessed by DFT calculations at the B3LYP/DGDZVP level of theory. Since the NMR data of (+)-1 are fully coincident with those from its enantiomer studied herein, the chirality of (5S,8S,9R,10S)-(+)-patagonic acid could also be determined. These experimental conclusions deeply complement the literature related to clerodane compounds biosynthesized in several families of plants of scientific interest. Full article

(This article belongs to the Section Natural Product Chemistry)

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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

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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

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6 pages, 1320 KiB

Open AccessShort Note

N-(2-((2-(1H-indol-3-yl)ethyl)carbamoyl)phenyl)furan-2-carboxamide

by Diyana Dimitrova, Iliyan Ivanov, Stanimir Manolov and Dimitar Bojilov

Molbank 2025, 2025(3), M2025; https://doi.org/10.3390/M2025 - 20 Jun 2025

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Abstract

In the present study, we describe the synthesis of N-(2-((2-(1H-indol-3-yl)ethyl)carbamoyl)phenyl)furan-2-carboxamide via a two-step reaction sequence. Initially, isatoic anhydride was reacted with tryptamine to afford the corresponding intermediate, which was subsequently subjected to acylation using furan-2-carbonyl chloride. The final product was [...] Read more.

In the present study, we describe the synthesis of N-(2-((2-(1H-indol-3-yl)ethyl)carbamoyl)phenyl)furan-2-carboxamide via a two-step reaction sequence. Initially, isatoic anhydride was reacted with tryptamine to afford the corresponding intermediate, which was subsequently subjected to acylation using furan-2-carbonyl chloride. The final product was comprehensively characterized by melting point analysis, ¹H and ¹³C NMR, HSQC, IR, and MS spectrometry. The combined spectroscopic and analytical data unequivocally confirm the successful synthesis and structural integrity of the target compound. Full article

(This article belongs to the Section Structure Determination)

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Molbank, Volume 2025, Issue 3 (September 2025) – 26 articles

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