scholarly journals Studies on the Derivatives of Biphenylene Oxide. VII. The Influence of Substitution on the Opening and Closing of the Furan-ring of Biphenylene Oxide

1942 ◽  
Vol 17 (1) ◽  
pp. 10-23 ◽  
Author(s):  
Seishi Yamashiro
Keyword(s):  
Furan Ring ◽  
Opening And Closing ◽  
Derivatives Of

Thiosemicarbazone derivatives of nickel and copper: the unprecedented coordination of furan ring in octahedral nickel(ii) and of triphenylphosphine in three-coordinate copper(i) complexes

2011 ◽  
Vol 40 (13) ◽  
pp. 3219 ◽  
Author(s):  
Tarlok Singh Lobana ◽  
Poonam Kumari ◽  
Rekha Sharma ◽  
Alfonso Castineiras ◽  
Ray Jay Butcher ◽  
...  
Keyword(s):  
Furan Ring ◽  
Derivatives Of

Cycloadditions of C-benzoyl-N-phenylnitrone with furocondensed derivatives

1981 ◽  
Vol 46 (10) ◽  
pp. 2421-2427 ◽  
Author(s):  
Lubor Fišera ◽  
Miloslava Dandárová ◽  
Jaroslav Kováč ◽  
Peter Mesko ◽  
Alžbeta Krutošíková
Keyword(s):  
Transition State ◽  
Furan Ring ◽  
High Yield ◽  
Dipolar Cycloaddition ◽  
Orbital Interactions ◽  
Derivatives Of

Single regioisomeric cycloadduct IIa was formed in a 35% yield upon cycloaddition of the title nitrone Ia with benzofuran. The 1,3-dipolar cycloaddition proceeded with derivatives of 4-R-furo[3,2-b]pyrrole V or VI to the furan ring to form only one regioisomer VIIa or VIIIa in a high yield (93-95%). Dehydrogenation of the latter with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone led to the nitrone X or XII. Also C,N-diphenylnitrone reacted with furopyrroles to afford the cycloadduct VIIIb. Exclusively endo-cycloadducts originated; their transition state was stabilized by secondary orbital interactions.

scholarly journals Benzobicyclo[3.2.1]octene Derivatives as a New Class of Cholinesterase Inhibitors

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4872
Author(s):  
Tena Čadež ◽  
Ana Grgičević ◽  
Ramiza Ahmetović ◽  
Danijela Barić ◽  
Nikolina Maček Hrvat ◽  
...  
Keyword(s):  
Ring Opening ◽  
Structural Adjustment ◽  
Cholinesterase Inhibitors ◽  
Furan Ring ◽  
Phenyl Substituent ◽  
Oxime Ether ◽  
New Class ◽  
Further Development ◽  
Derivatives Of ◽  
Acyl Derivatives

A library of amine, oxime, ether, epoxy and acyl derivatives of the benzobicyclo[3.2.1]octene were synthesized and evaluated as inhibitors of both human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The majority of the tested compounds exhibited higher selectivity for BChE. Structural adjustment for AChE seems to have been achieved by acylation, and the furan ring opening of furo-benzobicyclo[3.2.1]octadiene results for compound 51 with the highest AChE affinity (IC50 = 8.3 µM). Interestingly, its analogue, an oxime ether with a benzobicyclo[3.2.1]-skeleton, compound 32 was one of the most potent BChE inhibitors in this study (IC50 = 31 µM), but not as potent as endo-43, an ether derivative of the benzobicyclo[3.2.1]octene with an additional phenyl substituent (IC50 = 17 µM). Therefore, we identified several cholinesterase inhibitors with a potential for further development as potential drugs for the treatment of neurodegenerative diseases.

scholarly journals Studies toward bivalent κ opioids derived from salvinorin A: heteromethylation of the furan ring reduces affinity

2013 ◽  
Vol 9 ◽  
pp. 2916-2924 ◽  
Author(s):  
Thomas A Munro ◽  
Wei Xu ◽  
Douglas M Ho ◽  
Lee-Yuan Liu-Chen ◽  
Bruce M Cohen
Keyword(s):  
Furan Ring ◽  
Allosteric Modulation ◽  
Salvinorin A ◽  
Allosteric Modulators ◽  
Design Strategies ◽  
Binding Assays ◽  
Bivalent Ligand ◽  
Basic Nitrogen ◽  
Derivatives Of ◽  
Aspartate Residue

The recent crystal structure of the κ-opioid receptor (κ-OR) revealed, unexpectedly, that the antagonist JDTic is a bivalent ligand: in addition to the orthosteric pocket occupied by morphinans, JDTic also occupies a distinct (allotopic) pocket. Mutagenesis data suggest that salvinorin A (1) also binds to this allotopic pocket, adjacent to the aspartate residue that anchors the basic nitrogen atom of classical opiates (Asp138). It has been suggested that an H-bond donor appended to 1 might interact with Asp138, increasing affinity. Such a bivalent ligand might also possess altered functional selectivity. Based on modeling and known N-furanylmethyl opioid antagonists, we appended H-bond donors to the furan ring of 1. (Dimethylamino)methyl groups at C-15 or C-16 abolished affinity for κ-OR. Hydroxymethylation at C-16 was tolerated, but 15,16-bis-hydroxymethylation was not. Since allosteric modulators may go undetected in binding assays, we also tested these and other low-affinity derivatives of 1 for allosteric modulation of dynorphin A in the [35S]GTPγS assay. No modulation was detected. As an alternative attachment point for bivalent derivatives, we prepared the 2-(hydroxyethoxy)methyl ether, which retained high affinity for κ-OR. We discuss alternative design strategies for linked, fused or merged bivalent derivatives of 1.

scholarly journals Photocatalytic Oxygenation of Heterostilbenes—Batch versus Microflow Reactor

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 395
Author(s):  
Milena Mlakić ◽  
Anita Šalić ◽  
Matea Bačić ◽  
Bruno Zelić ◽  
Ivana Šagud ◽  
...  
Keyword(s):  
Furan Ring ◽  
Water Soluble ◽  
Reaction Pathways ◽  
Open Chain ◽  
Conversion Rates ◽  
Microflow Reactor ◽  
The Common ◽  
Thiophene Derivatives ◽  
Derivatives Of ◽  
Geometric Effects

On the basis of earlier results with furan and thiophene derivatives of benzobicyclo[3.2.1]octadiene, photocatalytic oxygenation of novel furo- and thieno heterostilbenes with water-soluble manganese(III) porphyrins offered suitable possibilities to study their reactivities and reaction pathways depending on the heteroatom and the catalyst charge. The experiments were carried out in two reactors types (batch and microflow) to investigate the geometric effects. NMR spectroscopy, GC, and UPLC/MS analyses were applied for identification and quantification of the products. As our results indicated, the 2-thienyl and the common p-tolyl groups in the starting compounds remained intact due to their stronger aromaticity. Hence, the thieno derivative underwent oxygenation only at the open-chain part of the molecule, and the rates of its reactions were much lower than those of the furyl analogue. The less stable furan ring was easily oxygenated, its products with highest ratios were 2-furanon derivatives. Epoxide formation occurred at the open-chain parts of both substrates preferably by the anionic catalyst. Nevertheless, the conversion rates of the substrates were higher with the cationic porphyrin, according to electrophilic attacks by photogenerated Mn(V)=O species. Additionally, the reactions were significantly faster in microflow reactors due to the more favorable circumstances of mass transfer, diffusion, and light penetration.

The Synthesis of 5-Hydroxy-3-methylnaphtho[2,3-c]furan-4,9-dione and 5,8-Dihydroxy-1-methylnaphtho[2,3-c]furan-4,9-dione

2003 ◽  
Vol 56 (7) ◽  
pp. 691 ◽  
Author(s):  
Matthew J. Piggott ◽  
Dieter Wege
Keyword(s):  
Furan Ring ◽  
Quinone Methide ◽  
Structural Representation ◽  
Naturally Occurring ◽  
Aloe Ferox ◽  
Key Steps ◽  
Derivatives Of

5-Hydroxy-3-methylnaphtho[2,3-c]furan-4,9-dione (1), a metabolite isolated from Aloe ferox and Bulbine capitata, has been synthesized by a sequence involving an annulation reaction between the anion of 4-methoxy-3-oxo-1,3-dihydroisobenzofuran-1-carbonitrile (8) and (E)-pent-3-en-2-one, followed by subsequent construction of the furan ring through allylic bromination, hydrolysis, and dehydration as the key steps. The formation of several unusual products observed in annulation reactions between (8) and O-protected derivatives of (E)-5-hydroxypent-3-en-2-one (9) can be rationalized by invoking the intermediacy of a reactive o-quinone methide. 5,8-Dihydroxy-1-methylnaphtho[2,3-c]furan-4,9-dione (2), another naturally occurring naphtho[2,3-c]furan-4,9-dione, has been prepared by a Friedel–Crafts acylation of 1,4-dimethoxybenzene with 2-methylfuran-3,4-dicarbonyl dichloride. Arguments are presented that 5,8-dihydroxynaphtho[2,3-c]furan-4,9-dione is a better structural representation than the alternative 4,9-dihydroxynaphtho[2,3-c]furan-5,8-dione tautomer in such systems, as the latter would contain a reactive isobenzofuran moiety.

Acid Catalyzed Furan Ring Transposition

10.1039/sp768 ◽  
2014 ◽  
Author(s):  
Jamsheena V. ◽  
Ravindra Phatake
Keyword(s):  
Furan Ring ◽  
Acid Catalyzed
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