2024

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6 pages, 954 KiB

Open AccessCommunication

Synthesis and Analytical Characterization of Cyclization Products of 3-Propargyloxy-5-benzyloxy-benzoic Acid Methyl Ester

by Matteo Mori, Giulia Cazzaniga, Donatella Nava and Elena Pini

Molbank 2024, 2024(2), M1806; https://doi.org/10.3390/M1806 - 16 Apr 2024

Viewed by 308

Abstract

In the context of our ongoing studies on chromane derivatives as inhibitors of the salicylate synthase from M. tuberculosis, we isolated a new, unexpected compound from the cyclization of 3-(propargyloxy)-5-benzyloxy-benzoic acid methyl ester. Its molecular structure was elucidated by means of 1D [...] Read more.

In the context of our ongoing studies on chromane derivatives as inhibitors of the salicylate synthase from M. tuberculosis, we isolated a new, unexpected compound from the cyclization of 3-(propargyloxy)-5-benzyloxy-benzoic acid methyl ester. Its molecular structure was elucidated by means of 1D and 2D NMR analyses, FT-IR, ESI-MS, and HRMS. Full article

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6 pages, 382 KiB

Open AccessShort Note

1,2-Dibenzoylthiosemicarbazide

by Burcă Ion, Badea Valentin, Todea Anamaria and Bercean Vasile-Nicolae

Molbank 2024, 2024(2), M1804; https://doi.org/10.3390/M1804 - 09 Apr 2024

Viewed by 327

Abstract

When 1-benzoylthiosemicarbazide (2) or thiosemicarbazide (1) were treated with benzoyl chloride in a basic medium, a mixture of two compounds was obtained: 1,2-dibenzoylthiosemicarbazide (3) and 1,4-dibenzoylthiosemicarbazide (4). To determine the structure of the novel compounds, [...] Read more.

When 1-benzoylthiosemicarbazide (2) or thiosemicarbazide (1) were treated with benzoyl chloride in a basic medium, a mixture of two compounds was obtained: 1,2-dibenzoylthiosemicarbazide (3) and 1,4-dibenzoylthiosemicarbazide (4). To determine the structure of the novel compounds, 2D NMR spectroscopy techniques such as ¹H-¹³C and ¹H-¹⁵N were employed. Full article

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Scheme 1

5 pages, 1296 KiB

Open AccessShort Note

2,3,5,6-Tetrafluoro-[N-(3-aminopropyl)-ε-caprolactam]-4-pyridine

by Chadron M. Friesen, Nathan J. Weeks and Scott T. Iacono

Molbank 2024, 2024(1), M1777; https://doi.org/10.3390/M1777 - 22 Feb 2024

Viewed by 810

Abstract

The title compound was synthesized at a near-quantitative yield using the nucleophilic aromatic substitution of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) with perfluoropyridine (PFP). The purity and structure were determined by NMR (¹H, ¹³C, ¹⁹F), GC-EIMS, and single-crystal X-ray crystallography. Full article

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2023

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5 pages, 811 KiB

Open AccessShort Note

(1R/S,7aS/R)-1-Benzyl-1-[2,8-bis(trifluoromethyl)quinolin-4-yl]-hexahydro-oxazolo[3,4-a]pyridin-3-one

by Dawid J. Kucharski and Przemysław J. Boratyński

Molbank 2024, 2024(1), M1756; https://doi.org/10.3390/M1756 - 30 Dec 2023

Viewed by 1288

Abstract

An unexpected diastereoselective C-alkylation of a mefloquine derivative in up to 57% yield was the result of an attempted Williamson etherification of Boc-mefloquine. The domino reaction involved oxazolidinone ring closure, deprotonation, and stereoselective carbon–carbon bond formation. The structure was confirmed with 2D NMR [...] Read more.

An unexpected diastereoselective C-alkylation of a mefloquine derivative in up to 57% yield was the result of an attempted Williamson etherification of Boc-mefloquine. The domino reaction involved oxazolidinone ring closure, deprotonation, and stereoselective carbon–carbon bond formation. The structure was confirmed with 2D NMR experiments. Full article

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Graphical abstract

9 pages, 1120 KiB

Open AccessShort Note

4-(5-Benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-2-nitrobenzamide

by Oscar Leonardo Avendaño Leon, Christophe Curti, Hussein El-Kashef, Youssef Kabri, Sébastien Redon and Patrice Vanelle

Molbank 2023, 2023(4), M1750; https://doi.org/10.3390/M1750 - 15 Dec 2023

Viewed by 1153

Abstract

As part of our ongoing attempt to broaden the applications of the amidoxime moiety as a potential source of new antileishmanial agents, this study focuses on the product 4-(5-Benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-2-nitrobenzamide. This unexpected amide was obtained in an 85% yield as the major product with [...] Read more.

As part of our ongoing attempt to broaden the applications of the amidoxime moiety as a potential source of new antileishmanial agents, this study focuses on the product 4-(5-Benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-2-nitrobenzamide. This unexpected amide was obtained in an 85% yield as the major product with a conventional amidoxime synthesis protocol (Ethanol/Na₂CO₃) involving the reaction of hydroxylamine and a nitrile group. The formation of this amide derivative instead of the expected amidoxime can be attributed to two complementary effects: the strong electron effect of the nitro group and the influence of ethanol, a polar protic solvent. Alternatively, the desired amidoxime derivative, 4-(5-benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-N′-hydroxy-2-nitrobenzimidamide, was obtained in an 80% yield by an alternative protocol (DMSO/KOtBu). This original compound, featuring a nitro group in the ortho position to the amidoxime, will be further evaluated, both in the field of medicinal chemistry and in other relevant areas, highlighting an unusual method to access amidoximes from hindered substrates. Full article

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Scheme 1

5 pages, 513 KiB

Open AccessEditorial

Editorial: Special Issue “Molecules from Side Reactions II”

by Stefano D’Errico and Annalisa Guaragna

Molbank 2023, 2023(4), M1740; https://doi.org/10.3390/M1740 - 20 Oct 2023

Viewed by 911

Abstract

This Special Issue, “Molecules from Side Reactions II”, belongs to the section Organic Synthesis of the journal Molbank and was launched in 2021, after the first edition, “Molecules from Side Reactions” [...] Full article

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5 pages, 1260 KiB

Open AccessShort Note

2-(1-Methoxycarbonyl-2-phenyleth-1-yl)-1-benzylpyridin-1-ium Bromide

by Lorenzo Suigo, Valentina Straniero and Ermanno Valoti

Molbank 2023, 2023(4), M1738; https://doi.org/10.3390/M1738 - 16 Oct 2023

Viewed by 896

Abstract

In this work, we report the unexpected conversion of a pyridine derivative into the corresponding N-benzylated pyridinium salt due to the presence of unreacted benzyl bromide in the crude product. This transformation was observed at room temperature in a solvent-free environment and [...] Read more.

In this work, we report the unexpected conversion of a pyridine derivative into the corresponding N-benzylated pyridinium salt due to the presence of unreacted benzyl bromide in the crude product. This transformation was observed at room temperature in a solvent-free environment and without any stirring. These interesting data show how pyridinium salts can be formed in mild conditions, avoiding high temperatures that could promote the degradation of the desired product. Full article

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5 pages, 2375 KiB

Open AccessShort Note

2,8-Dibromo-6H,12H-6,12-epoxydibenzo[b,f][1,5]dioxocine

by R. Alan Aitken, David B. Cordes, An Jie Ler and Aidan P. McKay

Molbank 2023, 2023(3), M1729; https://doi.org/10.3390/M1729 - 19 Sep 2023

Viewed by 905

Abstract

The title dibromodisalicylaldehyde, obtained as a by-product in the m-chloroperoxybenzoic acid oxidation of 5-bromo-2-(methoxymethoxy)benzaldehyde, has been characterised by IR and NMR spectroscopy and X-ray diffraction. The structure features two independent molecules with a π–π stacking interaction between them. Full article

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Graphical abstract

7 pages, 609 KiB

Open AccessShort Note

4-(4-Ethoxyphenyl)-5-(4-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one

by Ion Burcă, Valentin Badea, Calin Deleanu, Vasile-Nicolae Bercean and Francisc Péter

Molbank 2023, 2023(3), M1705; https://doi.org/10.3390/M1705 - 01 Aug 2023

Viewed by 891

Abstract

A new triazol-3-one resulted unexpectedly from the reduction reaction of a heterocyclic thioketone using sodium borohydride in pyridine containing a small amount of water. The structure of the new compound was characterised using FT-IR, 1D and 2D NMR, and HRMS spectroscopic methods. Full article

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Graphical abstract

9 pages, 1645 KiB

Open AccessCommunication

Diethyl 2-((aryl(alkyl)amino)methylene)malonates: Unreported Mycelial Growth Inhibitors against Fusarium oxysporum

by Willy-Fernando Cely-Veloza, Diego Quiroga and Ericsson Coy-Barrera

Molbank 2023, 2023(2), M1630; https://doi.org/10.3390/M1630 - 23 Apr 2023

Viewed by 1125

Abstract

This paper presents the discovery and development of antifungal agents against Fusarium oxysporum (Fox), a devastating plant pathogen. Diethyl 2-((arylamino)methylene)malonates (DAMMs) were formed as side-products during the synthesis of polysubstituted-2-pyridones through a three-component domino reaction and seemed to have antifungal activity [...] Read more.

This paper presents the discovery and development of antifungal agents against Fusarium oxysporum (Fox), a devastating plant pathogen. Diethyl 2-((arylamino)methylene)malonates (DAMMs) were formed as side-products during the synthesis of polysubstituted-2-pyridones through a three-component domino reaction and seemed to have antifungal activity against Fox. DAMMs are typically employed as intermediates or precursors to produce further bioactive compounds, but they have never been examined as antifungals. To confirm this latter characteristic, we employed a single-step procedure (i.e., the first step of the Gould-Jacobs reaction) to prepare five DAMMs (74–96% yields) which were subsequently evaluated against Fox in terms of their abilities to inhibit mycelial growth. The antifungal outcome was promising (0.013 µM < IC₅₀ < 35 µM), involving fungistatic or fungicide effects. This small group of active compounds showed differences in antifungal activity, constituting the basis of further studies to expand the DAMM chemical space and look for improved antifungal activity. Full article

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5 pages, 1305 KiB

Open AccessCommunication

Manganese(II) Bromide Coordination toward the Target Product and By-Product of the Condensation Reaction between 2-Picolylamine and Acenaphthenequinone

by Vera V. Khrizanforova, Robert R. Fayzullin and Yulia H. Budnikova

Molbank 2023, 2023(1), M1606; https://doi.org/10.3390/M1606 - 22 Mar 2023

Cited by 1 | Viewed by 1094

Abstract

A heteroleptic binuclear manganese complex was obtained and characterized by single-crystal X-ray diffraction. Manganese ions coordinate with the target product and by-product of the condensation reaction between 2-picolylamine and acenaphthenequinone are characterized by different geometries in the resulting complex. Full article

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6 pages, 1093 KiB

Open AccessShort Note

(Z)-2′-((Adamantan-1-yl)thio)-1,1′-dimethyl-2′,3′-dihydro-[2,4′-biimidazolylidene]-4,5,5′(1H,1′H,3H)-trione

by Vladimir Burmistrov, Vladimir Mokhov, Robert R. Fayzullin and Gennady M. Butov

Molbank 2023, 2023(1), M1585; https://doi.org/10.3390/M1585 - 14 Feb 2023

Viewed by 1260

Abstract

The title compound, (Z)-2′-((adamantan-1-yl)thio)-1,1′-dimethyl-2′,3′-dihydro-[2,4′-biimidazolylidene]-4,5,5′(1H,1′H,3H)-trione, was found to be a by-product of the reaction of 1,3-dehydroadamantane with 3-methyl-2-thioxoimidazolidin-4-one and characterized via single-crystal X-ray diffraction. Full article

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9 pages, 1136 KiB

Open AccessCommunication

Obtainment of Threo and Erythro Isomers of the 6-Fluoro-3-(2,3,6,7,8,9-hexahydronaphtho[2,3-b][1,4]dioxin-2-yl)-2,3-dihydrobenzo[b][1,4]dioxine-5-carboxamide

by Valentina Straniero, Lorenzo Suigo, Giulia Lodigiani and Ermanno Valoti

Molbank 2023, 2023(1), M1559; https://doi.org/10.3390/M1559 - 18 Jan 2023

Cited by 1 | Viewed by 1288

Abstract

2,6-difluorobenzamides have been deeply investigated as antibacterial drugs in the last few decades. Several 3-substituted-2,6-difluorobenzamides have proved their ability to interfere with the bacterial cell division cycle by inhibiting the protein FtsZ, the key player of the whole process. Recently, we developed a [...] Read more.

2,6-difluorobenzamides have been deeply investigated as antibacterial drugs in the last few decades. Several 3-substituted-2,6-difluorobenzamides have proved their ability to interfere with the bacterial cell division cycle by inhibiting the protein FtsZ, the key player of the whole process. Recently, we developed a novel family of 1,4-tetrahydronaphthodioxane benzamides, having an ethoxy linker, which reached sub-micromolar MICs towards Gram-positive Staphylococcus aureus and Bacillus subtilis. A further investigation of their mechanism of action should require the development of a fluorescent probe, and the consequent definition of a synthetic pathway for its obtainment. In the present work, we report the obtainment of an unexpected bicyclic side product, 6-fluoro-3-(2,3,6,7,8,9-hexahydronaphtho[2,3-b][1,4]dioxin-2-yl)-2,3-dihydrobenzo[b][1,4]dioxine-5-carboxamide, coming from the substitution of one aromatic fluorine by the in situ formed alkoxy group, in the final opening of an epoxide intermediate. This side product was similarly achieved, in good yields, by opening the ring of both erythro and threo epoxides, and the two compounds were fully characterized using HRMS, ¹H-NMR, ¹³C-NMR, HPLC and DSC. Full article

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2022

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8 pages, 788 KiB

Open AccessShort Note

(3-Methylene-2,3-dihydronaphtho[2,3-b][1,4]dioxin-2-yl)methanol

by Lorenzo Suigo, Giulia Lodigiani, Valentina Straniero and Ermanno Valoti

Molbank 2022, 2022(4), M1521; https://doi.org/10.3390/M1521 - 06 Dec 2022

Cited by 1 | Viewed by 1433

Abstract

(3-Methylene-2,3-dihydronaphtho[2,3-b][1,4]dioxin-2-yl)methanol was unexpectedly achieved as the main reaction product while applying a standard Johnson–Corey–Chaykovsky procedure to the 2,3-dihydronaphtho[2,3-b][1,4]dioxine-2-carbaldehyde, aiming at obtaining the corresponding epoxide. The structure of the recovered compound was confirmed through NMR and HRMS, the melting point [...] Read more.

(3-Methylene-2,3-dihydronaphtho[2,3-b][1,4]dioxin-2-yl)methanol was unexpectedly achieved as the main reaction product while applying a standard Johnson–Corey–Chaykovsky procedure to the 2,3-dihydronaphtho[2,3-b][1,4]dioxine-2-carbaldehyde, aiming at obtaining the corresponding epoxide. The structure of the recovered compound was confirmed through NMR and HRMS, the melting point was measured by DSC, and the organic purity was assessed using HPLC. We hypothesized the possible mechanism for the obtainment of this side product, which should involve the opening of the dioxane ring soon after the nucleophilic attack of the ylide to the carbonyl function. The consequent transfer of the negative charge allows the achievement of the phenolate function. The tautomer further rearranges, forming the unstable oxirane, which opening is favored by the acidic phenolic function, thus closing into the more stable six-membered ring compound. We confirmed the hypothesized reaction mechanism by applying the same reaction conditions while starting from the corresponding methyl ketone. This undesired compound, easily and quantitatively obtained by standard Johnson–Corey–Chaykovsky conditions, could pave the way to a new methodology for the obtainment of 2,3-disubstituted 1,4-naphthodioxanes, further derivatizable. Full article

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5 pages, 523 KiB

Open AccessShort Note

19β,28-Epoxy-18α-olean-3β-ol-2-furoate from Allobetulin (19β,28-Epoxy-18α-olean-3β-ol)

by Fulgentius Nelson Lugemwa

Molbank 2022, 2022(4), M1499; https://doi.org/10.3390/M1499 - 18 Nov 2022

Viewed by 1064

Abstract

The E ring of betulin rearranges and forms a cyclic ether when treated with an acid. Treatment of betulin with iodine generated hydrogen iodide in situ, which went on to promote the rearrangement at C-19 and C-20, followed by cyclization to form allobetulin. [...] Read more.

The E ring of betulin rearranges and forms a cyclic ether when treated with an acid. Treatment of betulin with iodine generated hydrogen iodide in situ, which went on to promote the rearrangement at C-19 and C-20, followed by cyclization to form allobetulin. A reaction of allobetulin with 2-furoyl chloride yielded 19β,28-Epoxy-18α-olean-3β-ol-2-furoate. Full article

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Scheme 1

6 pages, 1364 KiB

Open AccessShort Note

Dichloro{4-(4-chlorophenoxy)phthalazin-1-yl} methylphosphonic dichloride

by Dyhia Amrane, Omar Khoumeri, Patrice Vanelle and Nicolas Primas

Molbank 2022, 2022(3), M1439; https://doi.org/10.3390/M1439 - 05 Sep 2022

Viewed by 1421

Abstract

As part of our ongoing scaffold-hopping work on an antiplasmodial 2-trichloromethylquinazoline scaffold, we aimed to explore the 1-trichloromethylphthalazine scaffold as a potential new antimalarial series. Using previously chlorination conditions described by our lab to obtain a trichloromethyl group from a methyl group, we [...] Read more.

As part of our ongoing scaffold-hopping work on an antiplasmodial 2-trichloromethylquinazoline scaffold, we aimed to explore the 1-trichloromethylphthalazine scaffold as a potential new antimalarial series. Using previously chlorination conditions described by our lab to obtain a trichloromethyl group from a methyl group, we did not obtain the target compound; instead, we obtained a dichloro methylphosphonic dichloride side product 3. The nature of this compound was then characterized by NMR, HRMS and X-ray crystallography. The same issue was previously reported by Kato et al., starting from the 2-methyl-3-nitropyridine. Finally, compound 3, although not cytotoxic, was not active against P. falciparum, the parasite responsible for human malaria. Full article

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7 pages, 673 KiB

Open AccessShort Note

O6-[(2″,3″-O-Isopropylidene-5″-O-^tbutyldimethylsilyl)pentyl]-5′-O-^tbutyldiphenylsilyl-2′,3′-O-isopropylideneinosine

by Maria Marzano, Monica Terracciano, Vincenzo Piccialli, Ahmed Mahal, Roberto Nilo and Stefano D’Errico

Molbank 2022, 2022(1), M1345; https://doi.org/10.3390/M1345 - 01 Mar 2022

Cited by 3 | Viewed by 2604

Abstract

Cyclic adenosine diphosphate ribose (cADPR) is a cyclic nucleotide involved in the Ca²⁺ homeostasis. In its structure, the northern ribose, bonded to adenosine through an N1 glycosidic bond, is connected to the southern ribose through a pyrophosphate bridge. Due to the chemical [...] Read more.

Cyclic adenosine diphosphate ribose (cADPR) is a cyclic nucleotide involved in the Ca²⁺ homeostasis. In its structure, the northern ribose, bonded to adenosine through an N1 glycosidic bond, is connected to the southern ribose through a pyrophosphate bridge. Due to the chemical instability at the N1 glycosidic bond, new bioactive cADPR derivatives have been synthesized. One of the most interesting analogues is the cyclic inosine diphosphate ribose (cIDPR), in which the hypoxanthine replaced adenosine. The efforts for synthesizing new linear and cyclic northern ribose modified cIDPR analogues led us to study in detail the inosine N1 alkylation reaction. In the last few years, we have produced new flexible cIDPR analogues, where the northern ribose has been replaced by alkyl chains. With the aim to obtain the closest flexible cIDPR analogue, we have attached to the inosine N1 position a 2″,3″-dihydroxypentyl chain, possessing the two OH groups in a ribose-like fashion. The inosine alkylation reaction afforded also the O6-alkylated regioisomer, which could be a useful intermediate for the construction of new kinds of cADPR mimics. Full article

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Graphical abstract

8 pages, 5776 KiB

Open AccessShort Note

3-Isobutyl-5,5,7-tris(3-methylbut-2-en-1-yl)-1-phenyl-1,7-dihydro-4H-indazole-4,6(5H)-dione

by José Edmilson Ribeiro do Nascimento, Daniela Hartwig, Raquel Guimarães Jacob and Márcio Santos Silva

Molbank 2022, 2022(1), M1330; https://doi.org/10.3390/M1330 - 01 Feb 2022

Viewed by 1731

Abstract

Here we describe the functionalization of lupulone natural compound in obtaining 3-isobutyl-5,5,7-tris(3-methylbut-2-en-1-yl)-1-phenyl-1,7-dihydro-4H-indazole-4,6(5H)-dione. The lupulone-H-indazole derivative was prepared with 75% yield through the reaction between lupulone and phenyl-hydrazine employing SiO₂/ZnCl₂ (30% m/m) [...] Read more.

Here we describe the functionalization of lupulone natural compound in obtaining 3-isobutyl-5,5,7-tris(3-methylbut-2-en-1-yl)-1-phenyl-1,7-dihydro-4H-indazole-4,6(5H)-dione. The lupulone-H-indazole derivative was prepared with 75% yield through the reaction between lupulone and phenyl-hydrazine employing SiO₂/ZnCl₂ (30% m/m) as a support solid in a solvent-free condition. Based on the possibilities of products, a complete NMR structural characterization of this lupulone-H-indazole was performed by ¹H, ¹³C{¹H}, COSY, HSQC and HMBC NMR experiments, showing an important contribution in producing the first results related to lupulone reactivity. Full article

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2021

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7 pages, 1899 KiB

Open AccessShort Note

Poly[3-methyl-1,3-oxazolidin-2-iminium[µ₃-cyanido-tri-µ₂-cyanido-κ⁹C:N-tricuprate(I)]]

by Leena N. Rachid and Peter W. R. Corfield

Molbank 2021, 2021(3), M1259; https://doi.org/10.3390/M1259 - 26 Jul 2021

Viewed by 1626

Abstract

The unexpected formation of an oxazole ring has occurred during synthesis of a copper(I) cyanide network polymer as part of our ongoing studies of the structural chemistry of these networks. Crystals of the title compound were formed during the synthesis of a previously [...] Read more.

The unexpected formation of an oxazole ring has occurred during synthesis of a copper(I) cyanide network polymer as part of our ongoing studies of the structural chemistry of these networks. Crystals of the title compound were formed during the synthesis of a previously reported CuCN network solid containing protonated N-methylethanolamine and have been characterized by single crystal X-ray structure analysis. The structure shows well-defined oxazole-2-iminium cations sitting in continuous channels along the short a-axis of the crystal in a new three-dimensional copper(I) cyanide polymeric network. Evidently, a reaction has occurred between the cyanide ion and the protonated N-methylethanolamine base. Full article

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Graphical abstract

5 pages, 1259 KiB

Open AccessShort Note

N,N-Bis(hexyl α-d-acetylmannosyl) Acrylamide

by Atsushi Miyagawa, Shinya Ohno and Hatsuo Yamamura

Molbank 2021, 2021(3), M1255; https://doi.org/10.3390/M1255 - 22 Jul 2021

Viewed by 1986

Abstract

Glycosyl monomers for the assembly of multivalent ligands are typically synthesized using carbohydrates with biological functions and polymerizable functional groups such as acrylamide or styrene introduced into the carbohydrate aglycon, and monomers polymerized using a radical initiator. Herein, we report the acryloylation of [...] Read more.

Glycosyl monomers for the assembly of multivalent ligands are typically synthesized using carbohydrates with biological functions and polymerizable functional groups such as acrylamide or styrene introduced into the carbohydrate aglycon, and monomers polymerized using a radical initiator. Herein, we report the acryloylation of 6-aminohexyl α-d-mannoside and its conversion into the glycosyl monomer bearing an acrylamide group. The general acryloylation procedure afforded the desired N-hexyl α-d-acetylmannosyl acrylamide monomer as well as an unexpected compound with a close R_f value. The compounds were separated and analyzed by nuclear magnetic resonance spectroscopy and mass spectrometry, which revealed the unknown compound to be the bivalent N,N-bis(hexyl α-d-acetylmannosyl) acrylamide monomer, which contains two hexyl mannose units and one acrylamide group. To the best of our knowledge, this side reaction has not previously been disclosed, and may be useful for the construction of multivalent sugar ligands. Full article

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5 pages, 989 KiB

Open AccessShort Note

N-{2-[(3-Oxo-1,3-dihydro-2-benzofuran-1-yl)acetyl]phenyl}acetamide

by Ricaurte Rodríguez, Omar León, Felipe Quiroga and Jonnathan Cifuentes

Molbank 2021, 2021(3), M1244; https://doi.org/10.3390/M1244 - 02 Jul 2021

Viewed by 1978

Abstract

With the aim of obtaining different derivatives belonging to the isoindolo[2,1-a]quinoline family, we have synthesized a novel N-{2-[(3-oxo-1,3-dihydro-2-benzofuran-1-yl)acetyl]phenyl}acetamide derivative by a Claisen–Smichdt-type condensation reaction in 75% yield. Full article

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5 pages, 301 KiB

Open AccessCommunication

Unexpected Formation of 4-aryl-1-(Propane-2-ylidenehydrazono)-2,3-diazaspiro[5.5]undec-3-ene by the Reaction of Pyridazinethiones Derivatives with Hydrazine

by Csilla Sepsey Für, György Keglevich and Hedvig Bölcskei

Molbank 2021, 2021(3), M1243; https://doi.org/10.3390/M1243 - 02 Jul 2021

Viewed by 1882

Abstract

After making a new series of spiro[cycloalkane]pyridazinones with high Fsp³ character available, the new target was to synthesize derivatives comprising nitrogen-containing heterocycles, such as triazolo or tetrazolo rings. The corresponding thioxo derivatives (1a,b) seemed to be good starting [...] Read more.

After making a new series of spiro[cycloalkane]pyridazinones with high Fsp³ character available, the new target was to synthesize derivatives comprising nitrogen-containing heterocycles, such as triazolo or tetrazolo rings. The corresponding thioxo derivatives (1a,b) seemed to be good starting materials for the synthesis of tetrazolo derivatives. The reaction of the pyridazinethiones (1a,b) with hydrazine surprisingly resulted in Schiff bases (3a,b) deriving from the reaction of hydrazones (2a,b) with acetone. Full article

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Scheme 1

5 pages, 895 KiB

Open AccessCommunication

Unexpected Metal-Free Dehydrogenation of a β-Ketoester to a Phenol Using a Recyclable Oxoammonium Salt

by Fabrizio Politano, William P. Brydon, Jyoti Nandi and Nicholas E. Leadbeater

Molbank 2021, 2021(1), M1180; https://doi.org/10.3390/M1180 - 13 Jan 2021

Cited by 6 | Viewed by 2893

Abstract

The conversion of ethyl 2-oxocyclohexanecarboxylate to ethyl salicylate using an oxoammonium salt is reported. The dehydrogenation reaction is operationally simple and compares favorably with previous literature examples for the same transformation and expands the scope of oxoammonium salts as reagents for oxidative functionalization [...] Read more.

The conversion of ethyl 2-oxocyclohexanecarboxylate to ethyl salicylate using an oxoammonium salt is reported. The dehydrogenation reaction is operationally simple and compares favorably with previous literature examples for the same transformation and expands the scope of oxoammonium salts as reagents for oxidative functionalization processes. Full article

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Graphical abstract

2020

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3 pages, 159 KiB

Open AccessEditorial

Editorial: Special Issue “Molecules from Side Reactions”

by Stefano D’Errico

Molbank 2020, 2020(4), M1172; https://doi.org/10.3390/M1172 - 30 Nov 2020

Viewed by 1653

Abstract

Organic synthesis is a powerful tool that allows researchers to express their scientific creativity [...] Full article

6 pages, 1458 KiB

Open AccessShort Note

Poly[1,3-Dimethyltetrahydropyrimidin-2(1H)-iminium [tri-µ₂-cyanido-κ⁶C:N-dicuprate(I)]]

by Peter W. R. Corfield and Joseph R. Dayrit

Molbank 2020, 2020(4), M1170; https://doi.org/10.3390/M1170 - 24 Nov 2020

Cited by 2 | Viewed by 2251

Abstract

The title compound contains a guanidinium cation that was unexpectedly found during X-ray single crystal analysis of a copper(I) cyanide network expected to contain protonated N,N’-dimethyl-1,3-diaminopropane. The cation was presumably formed by reaction of the amine with cyanide ions in [...] Read more.

The title compound contains a guanidinium cation that was unexpectedly found during X-ray single crystal analysis of a copper(I) cyanide network expected to contain protonated N,N’-dimethyl-1,3-diaminopropane. The cation was presumably formed by reaction of the amine with cyanide ions in the aqueous sodium cyanide/copper cyanide mixtures used in the synthesis. The structure of the network solid features the guanidinium cation as a guest in an anionic two-dimensional polymeric framework with stoichiometry Cu₂(CN)₃⁻. Confirmation of the structure was provided by analytical, thermal gravimetric and infrared data. Full article

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5 pages, 1170 KiB

Open AccessShort Note

4′-(N-(Propan-1,2-dienyl)pyrrol-2-yl)-2,2′:6′,2″-terpyridine

by Jérôme Husson and Laurent Guyard

Molbank 2020, 2020(2), M1142; https://doi.org/10.3390/M1142 - 10 Jun 2020

Cited by 5 | Viewed by 2379

Abstract

A new pyrrole-substituted terpyridine derivative that possesses an allene moiety was obtained as an “unexpected” sole product during an attempt to alkylate the N-atom of pyrrole with propargyl bromide in order to obtain an alkyne-functionalized terpyridine. Full article

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Graphical abstract

6 pages, 819 KiB

Open AccessFeature PaperCommunication

Formation of an Isomeric Mixture of Dienynes Instead of a Diallene

by Susanne M. Petrova and Leiv K. Sydnes

Molbank 2020, 2020(2), M1133; https://doi.org/10.3390/M1133 - 11 May 2020

Cited by 1 | Viewed by 2169

Abstract

Attempts to convert 1,1,2,2,7,7,8,8-octaethoxyocta-3,5-diyne to a symmetric allene by reduction with lithium aluminum hydride failed. Instead reduction accompanied by isomerization occurred and afforded 1,1,2,7,8,8-hexaethoxyocta-2,6-dien-4-yne as a mixture of three isomers in 63% total isolated yield. Full article

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8 pages, 1272 KiB

Open AccessCommunication

Unexpected Seven-Membered Ring Formation for Muraymycin-Type Nucleoside-Peptide Antibiotics

by Kristin Leyerer, Stefan Koppermann and Christian Ducho

Molbank 2020, 2020(2), M1122; https://doi.org/10.3390/M1122 - 26 Mar 2020

Cited by 1 | Viewed by 2287

Abstract

Naturally occurring nucleoside-peptide antibiotics such as muraymycins or caprazamycins are of major interest for the development of novel antibacterial agents. However, the synthesis of new analogues of these natural products for structure–activity relationship (SAR) studies is challenging. In our synthetic efforts towards a [...] Read more.

Naturally occurring nucleoside-peptide antibiotics such as muraymycins or caprazamycins are of major interest for the development of novel antibacterial agents. However, the synthesis of new analogues of these natural products for structure–activity relationship (SAR) studies is challenging. In our synthetic efforts towards a muraymycin-derived nucleoside building block suitable for attachment to a solid support, we came across an interesting side product. This compound resulted from an undesired Fmoc deprotection with subsequent cyclization, thus furnishing a remarkable caprazamycin-like seven-membered diazepanone ring. Full article

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9 pages, 927 KiB

Open AccessCommunication

8-Fluoro-N-2-isobutyryl-2′-deoxyguanosine: Synthesis and Reactivity

by Andrei Solodinin, James Helmkay, Samuel Ollivier and Hongbin Yan

Molbank 2020, 2020(1), M1119; https://doi.org/10.3390/M1119 - 06 Mar 2020

Cited by 2 | Viewed by 2479

Abstract

3′,5′-O-Bis(tert-butyldimethylsilyl)-8-fluoro-N-2-isobutyryl-2′-deoxyguanosine was synthesized from 3′,5′-O-bis(tert-butyldimethylsilyl)-N-2-isobutyryl-2′-deoxyguanosine by the treatment with N-fluorobenzenesulfonimide. A similar fluorination reaction with 3′,5′-O-bis(tert-butyldimethylsilyl)-N-2-(N,N-dimethylformamidine)-2′-deoxyguanosine, however, failed to give [...] Read more.

3′,5′-O-Bis(tert-butyldimethylsilyl)-8-fluoro-N-2-isobutyryl-2′-deoxyguanosine was synthesized from 3′,5′-O-bis(tert-butyldimethylsilyl)-N-2-isobutyryl-2′-deoxyguanosine by the treatment with N-fluorobenzenesulfonimide. A similar fluorination reaction with 3′,5′-O-bis(tert-butyldimethylsilyl)-N-2-(N,N-dimethylformamidine)-2′-deoxyguanosine, however, failed to give the corresponding fluorinated product. It was found that 8-fluoro-N-2-isobutyryl-2′-deoxyguanosine is labile under acidic conditions, but sufficiently stable in dichloroacetic acid used in solid phase synthesis. Incorporation of 8-fluoro-N-2-isobutyryl-2′-deoxyguanosine into oligonucleotides through the phosphoramidite chemistry-based solid phase synthesis failed to give the desired products. Furthermore, treatment of 8-fluoro-N-2-isobutyryl-2′-deoxyguanosine with aqueous ammonium hydroxide did not give 8-fluoro-2′-deoxyguanosine, but led to the formation of a mixture consisting of 8-amino-N-2-isobutyryl-2′-deoxyguanosine and C8:5′-O-cyclo-2′-deoxyguanosine. Taken together, an alternative N-protecting group and possibly modified solid phase synthetic cycle conditions will be required for the incorporation of 8-fluoro-2′-deoxyguanosine into oligonucleotides through the phosphoramidite chemistry-based solid phase synthesis. Full article

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4 pages, 673 KiB

Open AccessCommunication

Synthesis and Isolation of Diastereomeric Anomeric Sulfoxides from a d-Mannuronate Thioglycoside Building Block

by Eleni Dimitriou and Gavin J. Miller

Molbank 2020, 2020(1), M1111; https://doi.org/10.3390/M1111 - 18 Jan 2020

Cited by 1 | Viewed by 2149

Abstract

Methyl [S-phenyl 4-O-acetyl-2,3-di-O-benzyl-1-thio-α-d-mannopyranoside (R/S)_S-oxide] uronate was synthesised from a thioglycoside mannosyl uronate donor in a 98% yield. By using one equivalent of meta-chloroperbenzoic acid (m-CPBA) as the sulphur oxidant, a smooth conversion to [...] Read more.

Methyl [S-phenyl 4-O-acetyl-2,3-di-O-benzyl-1-thio-α-d-mannopyranoside (R/S)_S-oxide] uronate was synthesised from a thioglycoside mannosyl uronate donor in a 98% yield. By using one equivalent of meta-chloroperbenzoic acid (m-CPBA) as the sulphur oxidant, a smooth conversion to the diastereomeric sulfoxide products was achieved. The product was fully characterized by ¹H, ¹³C and 2D NMR alongside MS analysis. Full article

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9 pages, 646 KiB

Open AccessCommunication

Unexpected Formation of Oxetanes during the Synthesis of Dodeco-6,7-diuloses

by Marius Bayer, Cäcilia Maichle-Mössmer and Thomas Ziegler

Molbank 2020, 2020(1), M1108; https://doi.org/10.3390/M1108 - 14 Jan 2020

Cited by 2 | Viewed by 2866

Abstract

During the synthesis of symmetrical dodeco-6,7-diuloses that are potential candidates for inhibition of glycosidases, an unanticipated epoxide-oxetane rearrangement was observed. A bicyclic sugar consisting of a glycal moiety and an anomeric esterified furanose was oxidized under epoxidation conditions (mCPBA/KF). The isolation [...] Read more.

During the synthesis of symmetrical dodeco-6,7-diuloses that are potential candidates for inhibition of glycosidases, an unanticipated epoxide-oxetane rearrangement was observed. A bicyclic sugar consisting of a glycal moiety and an anomeric esterified furanose was oxidized under epoxidation conditions (mCPBA/KF). The isolation of the pure epoxide was not possible since a rapid reversible conversion accompanied by the migration of the ester group took place and resulted in the formation of an unusual oxetane-bridged disaccharide scaffold. X-ray diffractometric structure elucidation and the suggested mechanism of the rearrangement are provided. Full article

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5 pages, 372 KiB

Open AccessShort Note

N′-Acetyl-3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine-4-carbohydrazide

by Júlio C. A. V. Soares and Luiza R. S. Dias

Molbank 2020, 2020(1), M1104; https://doi.org/10.3390/M1104 - 07 Jan 2020

Cited by 1 | Viewed by 2310

Abstract

Synthesis of N′-acetyl-3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine-4-carbohydrazide from the phenyl acetates of 3-acetyl-5-(3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b]pyridine-4-yl)-2,3-dihydro-1,3,4-oxadiazol-2-yl in alkaline medium and its characterization by spectroscopic methods. Full article

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Scheme 1

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6 pages, 2061 KiB

Open AccessShort Note

N-(2-Hydroxy-1,1-dimethylethyl)-3-methylbenzamide

by Hamad H. Al Mamari and Yousuf Al Lawati

Molbank 2020, 2020(1), M1099; https://doi.org/10.3390/M1099 - 19 Dec 2019

Cited by 5 | Viewed by 2612

Abstract

The title compound, N-(2-hydroxy-1,1-dimethylethyl)-3-methylbenzamide was synthesized by reacting 3-methylbenzoyl chloride or 3-methylbenzoic acid with 2-amino-2-methyl-1-propanol. In the present report, the synthesized target compound was fully characterized by various spectroscopic methods (¹H NMR, ¹³C NMR, IR, GC-MS), its composition confirmed [...] Read more.

The title compound, N-(2-hydroxy-1,1-dimethylethyl)-3-methylbenzamide was synthesized by reacting 3-methylbenzoyl chloride or 3-methylbenzoic acid with 2-amino-2-methyl-1-propanol. In the present report, the synthesized target compound was fully characterized by various spectroscopic methods (¹H NMR, ¹³C NMR, IR, GC-MS), its composition confirmed by elemental analysis, and its structure determined and confirmed by X-ray analysis. The importance of this compound lies in its possession of an N,O-bidentate directing group. Such a structural motif is potentially suitable for metal-catalyzed C–H bond functionalization reactions. Full article

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5 pages, 1069 KiB

Open AccessFeature PaperShort Note

5′-Chloro-5′-deoxy-2′,3′-O-isopropylidene-6-fluoro nebularine

by Andrea Patrizia Falanga, Maria Marzano, Monica Terracciano and Stefano D'Errico

Molbank 2019, 2019(4), M1097; https://doi.org/10.3390/M1097 - 13 Dec 2019

Cited by 1 | Viewed by 2391

Abstract

In this paper, we report on the synthesis and spectroscopic characterization of the novel nucleoside 5′-chloro-5′-deoxy-2′,3′-O-isopropylidene-6-fluoro nebularine, obtained as a side product during the second step of the synthesis of 5′-fluoro-5′-deoxy-5-aminoimidazole-4-carboxamide-β-d-riboside (5′-F-AICAR), a non-phosphorylable analogue of 5-aminoimidazole-4-carboxamide-β-d-riboside (AICAR). Full article

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8 pages, 973 KiB

Open AccessCommunication

Access to d- and l-Psicose Derivatives via Hydroxy Methylation of Ribono Lactone

by Michael R. Imrich and Thomas Ziegler

Molbank 2019, 2019(4), M1096; https://doi.org/10.3390/M1096 - 10 Dec 2019

Cited by 1 | Viewed by 3108

Abstract

2,3,5-Tri-O-benzyl- and 2,3,5-tri-O-methyl-d-ribono-γ-lactone were converted with (methoxyethoxymethoxy)methyl and benzyloxy tributylstannane into the corresponding protected d-psicoses as mixtures of anomers in 31%–72% yield. Treatment of 2,3,5-tri-O-methyl-l-ribono-γ-lactone with benzyloxy tributylstannane afforded the corresponding l [...] Read more.

2,3,5-Tri-O-benzyl- and 2,3,5-tri-O-methyl-d-ribono-γ-lactone were converted with (methoxyethoxymethoxy)methyl and benzyloxy tributylstannane into the corresponding protected d-psicoses as mixtures of anomers in 31%–72% yield. Treatment of 2,3,5-tri-O-methyl-l-ribono-γ-lactone with benzyloxy tributylstannane afforded the corresponding l-psicose derivative as an anomeric mixture in 72% yield. Both methylated psicoses were further converted into 1,2-O-isopropylidene-3,4,6-tri-O-methyl-d- and l-psicofuranosides, the respective α- and β-anomers of which could be separated and characterized. Full article

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4 pages, 407 KiB

Open AccessCommunication

Pyridine-Imidazlolium Salts: Oxidatively Cleavage of N-C Bond via Nitration

by Dumitrela Cucu (Diaconu) and Violeta Mangalagiu

Molbank 2019, 2019(4), M1095; https://doi.org/10.3390/M1095 - 23 Nov 2019

Cited by 3 | Viewed by 2184

Abstract

Azaheterocycles derivatives with pyridine-imidazole skeleton are compounds of great value for medicinal chemistry. We report herein the nitration of 1,1′-(pyridine-2,6-diylbis(methylene))bis{3-[2-(4-nitrophenyl)-2-oxoethyl]-1H-imidazol-3-ium} bromide using a typical mixture of nitric and sulphuric acid. The nitration occur with the oxidative cleavage of N–C bond between [...] Read more.

Azaheterocycles derivatives with pyridine-imidazole skeleton are compounds of great value for medicinal chemistry. We report herein the nitration of 1,1′-(pyridine-2,6-diylbis(methylene))bis{3-[2-(4-nitrophenyl)-2-oxoethyl]-1H-imidazol-3-ium} bromide using a typical mixture of nitric and sulphuric acid. The nitration occur with the oxidative cleavage of N–C bond between imidazolium ring and methylene group. Full article

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Figure 1

6 pages, 1522 KiB

Open AccessShort Note

(E)-4-(3-Phenylisoxazol-5-yl)but-3-en-2-one

by Nattawut Sawengngen, Alexandra A. Kolodina and Olga V. Serdyuk

Molbank 2019, 2019(3), M1081; https://doi.org/10.3390/M1081 - 18 Sep 2019

Cited by 4 | Viewed by 1956

Abstract

(E)-4-(3-Phenylisoxazol-5-yl)but-3-en-2-one was synthesized via the oxidative ring opening reaction of 2-(5-methylfuran-2-yl)-1-phenylethanone oxime, followed by the iodine mediated isomerization. Full article

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