Beilstein Journal of Organic Chemistry This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Rhodium-catalyzed intramolecular reductive aldol-type cyclization: Application for the synthesis of a chiral necic acid lactone
Abstract A rhodium-catalyzed intramolecular reductive aldol-type cyclization is described to give β-hydroxylactones with high diastereoselectivities. The stereoselectivity of this cyclization is highly solvent dependent and can give syn- or anti-β-hydroxylactones with high diastereoselectivity. This methodology was also applied to the synthesis of a chiral necic acid lactone which is a structural component of the pyrrolizidine alkaloid monocrotaline. Beilstein J. Org. Chem. 2022, 18, 1642–1648. doi:10.3762/bjoc.18.176 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - December 2, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: β -hydroxylactone intramolecular reductive aldol cyclization necic acid lactone rhodium catalyst Full Research Paper Source Type: research

Synthesis of ( − )-halichonic acid and ( − )-halichonic acid B
Abstract The first syntheses of the amino acids (–)-halichonic acid and (–)-halichonic acid B have been achieved in ten steps starting from commercially available (−)-α-bisabolol. The optimized synthetic route includes a new purification method for isolating (−)-7-amino-7,8-dihydrobisabolene in enantiomerically pure form via recrystallization of its benzamide derivative. The key intramolecular aza-Prins reaction forms the characteristic 3-azabicyclo[3.3.1]nonane ring system of halichonic acid along with the lactonized form of halichonic acid B in an 8:1 ratio. Optical rotation measurements conf...
Source: Beilstein Journal of Organic Chemistry - December 1, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkaloid amino acid aza-Prins reaction cascade reaction natural product Full Research Paper Source Type: research

Synthetic study toward the diterpenoid aberrarone
Abstract An approach to aberrarone, an antimalarial diterpenoid natural product with tetracyclic skeleton is reported. Key to the stereoselective preparation of the 6-5-5 tricyclic skeleton includes the mediation of Nagata reagent for constructing the C1 all-carbon quaternary centers and gold-catalyzed cyclopentenone synthesis through C–H insertion. Beilstein J. Org. Chem. 2022, 18, 1625–1628. doi:10.3762/bjoc.18.173 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - November 30, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aberrarone C – H insertion gold Pauson Khand total synthesis Letter Source Type: research

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine
Abstract Imidazopyridines and pyrrolopyrimidines are an important class of compounds in medicinal chemistry. They can also be considered as deaza-modified purine nucleobases, and as such have attracted a lot of interest recently in the context of RNA atomic mutagenesis. In particular, for 1-deazaguanine (c1G base), a significant increase in demand is apparent. Synthetic access is challenging and the few reports found in the literature suffer from the requirement of hazardous intermediates and harsh reaction conditions. Here, we report a new six-step synthesis for c1G base, starting from 6-iodo-1-deazapurine. The key transf...
Source: Beilstein Journal of Organic Chemistry - November 29, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: deazapurine heterocycles imidazopyridines nucleoside nucleotides pyrrolopyrimidines RNA atomic mutagenesis Full Research Paper Source Type: research

One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles
Abstract A novel four-component reaction in one pot as an atom- and step-economic process was developed to synthesize diastereoselectively spirooxindolepyrrolothiazoles through sequential N,S-acetalation of aldehydes with cysteine and decarboxylative [3 + 2] cycloaddition with olefinic oxindoles. High synthetic efficiency, operational simplification and reaction process economy using EtOH as solvent, and only releasing CO2 and H2O as side products confer this approach favorable in green chemistry metrics analysis. Beilstein J. Org. Chem. 2022, 18, 1607–1616. doi:10.3762/bjoc.18.171 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - November 28, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: azomethine ylides cascade double annulations N,S-acetalation pyrrolothiazoles spirooxindole Full Research Paper Source Type: research

Preparation of β -cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene
Abstract A series of β-cyclodextrin dimers selectively permethylated on the primary or secondary rim with two different types of spacers have been synthesized effectively utilizing conventional and newly developed methods. Their structure analyses by 1H NMR and NOESY NMR imply the dependence of molecular symmetry on the type of spacer. The ability of synthesized dimers to increase the solubility of tetracene in DMSO was evaluated and compared to native cyclodextrins and their methylated derivatives. The newly synthesized compounds expressed better effectiveness than other tested supramolecular hosts. Beilstein J. Org...
Source: Beilstein Journal of Organic Chemistry - November 25, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: cyclodextrin dimer methylation solubilization tetracene Full Research Paper Source Type: research

Formal total synthesis of macarpine via a Au(I)-catalyzed 6-endo-dig cycloisomerization strategy
Abstract The formal total synthesis of macarpine was accomplished by the construction of a naphthol intermediate in Ishikawa’s synthetic route with two different synthetic routes. The convergent synthetic strategies feature the utilization of Au(I)-catalyzed cycloisomerizations of a 1,5-enyne and alkynyl ketone substrates, which were prepared by Sonogashira coupling reactions. Beilstein J. Org. Chem. 2022, 18, 1589–1595. doi:10.3762/bjoc.18.169 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - November 23, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: benzo[c]phenanthridine alkaloids 1,5-enyne formal total synthesis gold catalysis macarpine Letter Source Type: research

Functionalization of imidazole N-oxide: a recent discovery in organic transformations
Abstract Nowadays heterocyclic compounds are widely used in medicinal chemistry and industry to develop life-saving drugs and medicines. Imidazole is one of the pharmacologically important heterocyclic motifs found in widely used and well-known medicines and bioactive molecules. The applications of imidazole derivatives displaying various biological activities, motivated researchers for the development of more potent and significant drugs containing imidazole moieties. The formation of imidazole derivatives can be achieved using imidazole N-oxide as starting material. In this review, the scope of substrates and reaction me...
Source: Beilstein Journal of Organic Chemistry - November 22, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: functionalization imidazole N-oxide mechanistic insights multicomponent reaction nucleophilic substitution reaction Review Source Type: research

Simple synthesis of multi-halogenated alkenes from 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane)
Abstract A series of aryl fluoroalkenyl ethers that contain chlorine and bromine as well as fluorine atoms were prepared in moderate to good yields via the reactions of phenols and 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane) in the presence of KOH. This simple reaction enabled the construction of highly halogenated compounds with the potential for further functionalization. The reaction involved a highly reactive difluoroethylene intermediate, which was produced by the reaction between halothane and KOH. Beilstein J. Org. Chem. 2022, 18, 1567–1574. doi:10.3762/bjoc.18.167 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - November 21, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aryl 1-monofluorovinyl ether electrophilic 1,1-difluoroethene halothane multi-halogenated alkene phenol Full Research Paper Source Type: research

Solid-phase total synthesis and structural confirmation of antimicrobial longicatenamide A
Abstract Longicatenamides A–D are cyclic hexapeptides isolated from the combined culture of Streptomyces sp. KUSC_F05 and Tsukamurella pulmonis TP-B0596. Because these peptides are not detected in the monoculture broth of the actinomycete, they are key tools for understanding chemical communication in the microbial world. Herein, we report the solid-phase total synthesis and structural confirmation of longicatenamide A. First, commercially unavailable building blocks were chemically synthesized with stereocontrol. Second, the peptide chain was elongated via Fmoc-based solid-phase peptide synthesis. Third, the peptide...
Source: Beilstein Journal of Organic Chemistry - November 18, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: antimicrobial longicatenamides peptidic natural product solid-phase synthesis total synthesis Full Research Paper Source Type: research

A study of the DIBAL-promoted selective debenzylation of α -cyclodextrin protected with two different benzyl groups
Abstract An α-cyclodextrin protected with 2,4-dichlorobenzyl groups on the primary alcohols and ordinary benzyl groups on the secondary alcohols was prepared and subjected to DIBAL (diisobutylaluminum hydride)-promoted selective debenzylation. Debenzylation proceeded by first removing two dichlorobenzyl groups from the 6A,D positions and then removing one or two benzyl groups from the 3A,D positions. Beilstein J. Org. Chem. 2022, 18, 1553–1559. doi:10.3762/bjoc.18.165 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - November 17, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aluminum hydrides cyclodextrin debenzylation 2,4-dichlorobenzyl selective Full Research Paper Source Type: research

Using UHPLC – MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library
Abstract In order to further expand the NatureBank open access compound library, chemical investigations of the Australian marine sponge, Ianthella basta, were undertaken since UHPLC–MS analysis of the extract from this sponge indicated the presence of a new alkaloid. Large-scale extraction and mass-directed isolation studies on the CH2Cl2/MeOH I. basta extract resulted in the purification of a new bromotyrosine-derived alkaloid, 5-debromopurealidin H (1), along with the known marine natural product, ianthesine E (2). The chemical structure of the new compound was determined following detailed spectroscopic and spect...
Source: Beilstein Journal of Organic Chemistry - November 15, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: alkaloid anthelmintic biodiscovery bromotyrosine 5-debromopurealidin H Ianthella NatureBank sponge Full Research Paper Source Type: research

Efficient synthesis of aziridinecyclooctanediol and 3-aminocyclooctanetriol
Abstract Cyclooctene endoperoxide was used as the key compound for the synthesis of aziridinecyclooctanediol and 3-aminocyclooctanetriol. Reduction of the cyclooctene endoperoxide, prepared by photooxygenation of cis,cis-1,3-cyclooctadiene, with zinc gave a cyclooctenediol and then benzylation of the hydroxy group yielded dibenzylated cyclooctene. Oxidation of the latter compound by OsO4/NMO followed by mesylation of the hydroxy group provided bis(benzyloxy)cyclooctane-1,2-diyl dimethanesulfonate. Reaction of the bis(benzyloxy)cyclooctane-1,2-diyl dimethanesulfonate with NaN3 gave 2-azido-3,8-bis(benzyloxy)cyclooctyl metha...
Source: Beilstein Journal of Organic Chemistry - November 11, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: aminocyclitols aminocyclooctanetriol azides aziridines aziridinecyclooctanediol Full Research Paper Source Type: research

A facile approach to spiro[dihydrofuran-2,3'-oxindoles] via formal [4 + 1] annulation reaction of fused 1H-pyrrole-2,3-diones with diazooxindoles
Abstract There has been developed an easy synthetic approach to spiro[dihydrofuran-2,3'-oxindoles] via a highly diastereoselective formal [4 + 1] cycloaddition reaction of [e]-fused 1H-pyrrole-2,3-diones with diazooxindoles. The described novel heterocyclic systems are heteroanalogues of antimicrobial and antibiofilm fungal metabolites. The developed reaction represents the first example of involving 1H-pyrrole-2,3-diones fused at the [e]-side in a [4 + 1] annulation reaction. Beilstein J. Org. Chem. 2022, 18, 1532–1538. doi:10.3762/bjoc.18.162 (Source: Beilstein Journal of Organic Chemistry)
Source: Beilstein Journal of Organic Chemistry - November 10, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: [4 1] annulation catalyst-free diazooxindole 1H-pyrrole-2,3-diones spirooxindole Full Research Paper Source Type: research

New triazole-substituted triterpene derivatives exhibiting anti-RSV activity: synthesis, biological evaluation, and molecular modeling
Abstract Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infections in infants. Currently, ribavirin, a nucleoside analog containing a 1,2,4-triazole-3-carboxamide moiety, is a first-line drug for its treatment, however, its clinical use has been limited due to its side effects. Here, we designed two new nitroaryl-1,2,3-triazole triterpene derivatives as novel anti-RSV drugs. Their anti-RSV and cytotoxic activity were evaluated in vitro, RSV protein F gene effects by RT-PCR and molecular modeling with inosine monophosphate dehydrogenase (IMPDH) were performed. Compound 8 was the best per...
Source: Beilstein Journal of Organic Chemistry - November 9, 2022 Category: Chemistry Authors: Beilstein Journal of Organic Chemistry - Syndicated Feeds Tags: antiviral betulinic acid bioisosterism respiratory syncytial virus triterpene ursolic acid Full Research Paper Source Type: research