ChemInform Abstract: A Short Synthesis of Pyridines from Deprotonated α-Aminonitriles by an Alkylation/RCM Sequence.

Absolute Configuration Determination of 2,3-Dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles Using Chiroptical Methods at Different Wavelengths

A correlation between the absolute configuration and chiroptical properties of nonracemic 1,6,7-trisubstituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles was studied. A series of 16 novel representatives were prepared by Cu-catalyzed [3 + 2] cycloadditions of racemic (Z)-2-benzylidene-5-oxopyrazolidin-2-ium-1-ides to tert-butyl (S)-(3-oxopent-4-yn-2-yl)carbamate, and their structures were determined by NMR, VCD, ECD, and X-ray diffraction. A clear correlation between the sign of specific rotation and configuration at position C(1) allows for easy determination of the absolute configuration of 1,6,7-trisubstituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by ECD and NMR. While VCD, requirin…

A short synthesis of pyridines from deprotonated α-aminonitriles by an alkylation/RCM sequence

Abstract α-Aminonitriles can serve as versatile key precursors for the synthesis of nitrogen containing heterocycles. After unsuccessful trials involving the [1,2]-Stevens rearrangement of nitrile-stabilized ammonium ylides, we herein report a simple three-step synthesis of substituted pyridines based on an alkylation/ring-closing metathesis/aromatization sequence.

An efficient and practical synthesis of [2-11C]indole via superfast nucleophilic [11C]cyanation and RANEY® Nickel catalyzed reductive cyclization

A rapid method for the synthesis of carbon-11 radiolabeled indole was developed using a sub-nanomolar quantity of no-carrier-added [(11)C]cyanide as radio-precursor. Based upon a reported synthesis of 2-(2-nitrophenyl)acetonitrile (), a highly reactive substrate 2-nitrobenzyl bromide () was evaluated for nucleophilic [(11)C]cyanation. Additionally, related reaction conditions were explored with the goal of obtaining of highly reactive 2-(2-nitrophenyl)-[1-(11)C]acetonitrile () while inhibiting its rapid conversion to 2,3-bis(2-nitrophenyl)-[1-(11)C]propanenitrile (). Next, a RANEY® Nickel catalyzed reductive cyclization method was utilized for synthesizing the desired [2-(11)C]indole with h…

Chemical constituents of the root wood of Erythrina sacleuxii and determination of the absolute configuration of suberectin

Phytochemical investigation on the root wood of Erythrina sacleuxii (Leguminosae) led to the isolation of nine secondary metabolites (1-9). Compound 1 was isolated from the genus Erythrina for the first time. The pure compounds were identified on the basis of comprehensive spectroscopic and spectrometric analyses, while their absolute configurations were determined based on chiroptical measurements. Compounds 5 and 6 showed weak antifungal activity against Pyricularia oryzae with MIC values of 20 µg/mL.
  
 Bull. Chem. Soc. Ethiop. 2020, 34(1), 135-140.
 DOI: https://dx.doi.org/10.4314/bcse.v34i1.12

Polyethylene bio-degradation by caterpillars?

In their recent paper on the degradation of polyethylene by caterpillars of the wax moth Galleria melonella, Bombelli et al.[1] report various experiments, including microscopic and spectroscopic data which the authors believe support the chemical digestion of the polymers by these insects. While the biodegradation of mostly inert artificial polymers is definitely a very interesting research field, we must respectfully disagree with the methodology and conclusions from this paper.

Characterization of the synthetic cannabinoid MDMB-CHMCZCA

The synthetic cannabinoid MDMB-CHMCZCA was characterized by various spectroscopic techniques including NMR spectroscopy and tandem mass spectrometry. The synthetic sample was found to be of S-configuration by VCD spectroscopy and comparison of the data with DFT calculations, while ECD spectroscopy was found to be inconclusive in this case. The enantiomeric purity of samples from test purchases and police seizures was assessed by a self-developed chiral HPLC method.

Total synthesis and biological evaluation of seven new anti-inflammatory oxacyclododecindione-type macrolactones

Through variation of our previously published total synthesis of two highly active anti-inflammatory macrolactones from the oxacyclododecindione family (J. Tauber, M. Rohr, T. Walter, G. Erkel and T. Opatz, Org. Biomol. Chem., 2015, 13, 7813-7821), seven new representatives of this compound class were prepared. Substitution of the 14-hydroxy group in oxacyclododecindione with a methyl substituent provided a readily accessible non-natural analogue which has similar pharmacological properties to the scarcely available natural product. Since the producible amount of substance is therefore no longer restricted by low fermentation yields, extensive in vivo studies become possible for the first t…

CCDC 1998325: Experimental Crystal Structure Determination

Related Article: Carina Weber, Nina Vierengel, Thorsten Walter, Torsten Behrendt, Tobias Lucas, Gerhard Erkel, Till Opatz|2020|Org.Biomol.Chem.|18|5906|doi:10.1039/D0OB00958J

CCDC 1998326: Experimental Crystal Structure Determination

Related Article: Carina Weber, Nina Vierengel, Thorsten Walter, Torsten Behrendt, Tobias Lucas, Gerhard Erkel, Till Opatz|2020|Org.Biomol.Chem.|18|5906|doi:10.1039/D0OB00958J

CCDC 1497003: Experimental Crystal Structure Determination

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CCDC 1998324: Experimental Crystal Structure Determination

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CCDC 1497004: Experimental Crystal Structure Determination

Related Article: Eva Pušavec Kirar, Uroš Grošelj, Amalija Golobič, Franc Požgan, Stefan Pusch, Carina Weber, Lars Andernach, Bogdan Štefane, Till Opatz, Jurij Svete|2016|J.Org.Chem.|81|11802|doi:10.1021/acs.joc.6b02270

CCDC 1497005: Experimental Crystal Structure Determination

Related Article: Eva Pušavec Kirar, Uroš Grošelj, Amalija Golobič, Franc Požgan, Stefan Pusch, Carina Weber, Lars Andernach, Bogdan Štefane, Till Opatz, Jurij Svete|2016|J.Org.Chem.|81|11802|doi:10.1021/acs.joc.6b02270

CCDC 1521512: Experimental Crystal Structure Determination

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