Design, Synthesis and Application of Spiro[4.5]cyclohexadienones via One-pot Sequential p-Hydroxybenzylation/Oxidative Dearomatization

2021 ◽  
Author(s):  
Vaibhav B. Patil ◽  
Jagadeesh Babu Nanubolu ◽  
Rambabu Chegondi

One-pot sequential p-hydroxybenzylation/oxidative dearomatization/spiroannulation has been designed for the efficient construction of tetrahydrofuran containing spiro-cyclohexadienones. This reaction proceeds through the p-hydroxybenzylation of 1,3-diketones with p-hydroxybenzyl alcohol via quinone methide formation...

2019 ◽  
Vol 16 (5) ◽  
pp. 512-521 ◽  
Author(s):  
Nidhi Rani ◽  
Randhir Singh

Background: A series of novel substituted 2-mercaptoimidazoles was synthesised efficiently and in high yields using one-pot synthesis from m-hydroxyacetophenones. Methods: The structures of the newly synthesized compounds were established, their molecular activity was investigated against some bacteria and fungi were further validated using molecular docking study. Results: Reaction of o-hydroxyphenacylbromide (2) with substituted aniline and KSCN, in the presence of catalyst p-toluene sulfonic acid afforded 4(a-r) in good yield. The structure of compounds (4a-r) was confirmed by IR, NMR and MS. Conclusion: The compounds exhibited excellent antimicrobial potency against the tested microorganism.


1979 ◽  
Vol 44 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Milan Souček

Competitive hydration and isomerisation of the quinone methide I at 25 °C in an aqueous medium in the region of pH 2.4-13.0 was studied spectrophotometrically. The only reaction products in the studied range of pH are 4-hydroxybenzyl alcohol (II) and 4-hydroxystyrene (III). The form of the overall rate equation corresponds to a general acid-base catalysis. The mechanism of both reactions for three markedly separated pH regions is discussed on the basis of kinetic data and solvent deuterium effect.


Author(s):  
Elena V. Stepanova ◽  
Andrei I. Stepanov

The results of our study of the pathways of selective reactivity of 3-amino-4-(5-chloromethyl-1,2,4-oxadiazole-3-yl)furazan versus 5-unsubstituted or 5-methyl and 5-trifluoromethyl substituted 4-(5R-1,2,4-oxadiazole-3-yl)furazans (R = H, Me, CF3) towards the action of hydrazine are discussed. If the reductive opening of 1,2,4-oxadiazole ring in unsubstituted at the С-5 atom (1,2,4-oxadiazol-3-yl)furazan derivatives under the treatment with hydrazine can be used as a method for the preparation of a range of amidrazones of 4-R-furazan-3-carboxylic acid. 3-amino-4-(5-trifluoromethyl-1,2,4-oxadiazol-3-yl)furazan with hydrazine gives amidoxime of 4-aminofurazan-3-carboxylic acid. 3-amino-4-(5-methyl-1,2,4-oxadiazol-3-yl) furazan is inert to the action of hydrazine, on the contrary the reaction of 3-amino-4-(5-chloromethyl-1,2,4-oxadiazole-3-yl)furazan with hydrazine leads to oxidation of chloromethyl group of titled compound to the carbonyl one. In this case the product of reaction of 3-amino-4-(5-chloromethyl-1,2,4-oxadiazole-3-yl)furazan with hydrazine was isolated in a form of corresponding hydrazonomethyl derivative notably as 3-amino-4-(5-hydrazonomethyl-1,2,4-oxadiazole-3-yl)furazan. A possible reaction mechanism for the formation of hydrazonomethyl group by oxidation reaction of chloromethyl group by hydrazine is proposed. 3-Amino-4-(5-hydrazonomethyl-1,2,4-oxadiazol-3-yl)furazan undergoes a transhydrazination reaction with semicarbazide and thiosemicarbazide. But our attempts to its hydrolysis for the purpose to obtain free aldehyde were unsuccessful. Thus, hydrolysis of hydrazonomethyl derivative in acetic acid in the presence of catalytic amount of sulfuric acid results in azine – N,N'-bis(3-(4-aminofurazan-3-yl)-1,2,4-oxadiazol-5-ylmethylyden)hydrazine – precipitation, long-duration boiling in hydrochloric acid leads to Kishner-Wolff reduction of the carbonyl group to 3-amino-4-(5-methyl-1,2,4-oxadiazol-3-yl)furazan, and hydrolysis in alkaline medium leads to 1,2,4-oxadiazole ring opening to amidoxime of 4-aminofurazan-3-carboxylic acid. Synthesis of 3-amino-4-(5-chloromethyl-1,2,4-oxadiazole-3-yl)furazan (R = CH2Cl) was carried out by condensation of amidoxime of 4-aminofurazan-3-carboxylic acid with an excess of chloroacetyl chloride in toluene at elevated temperature. The reaction proceeds through formation of intermediate product – 3-chloromethylamino-4-(5-chloromethyl-1,2,4-oxadiazol-3-yl)furazan. Removing of N-chloroacetyl group in such obtained intermediate was performed by hydrolysis in acidic media. One-pot synthesis without the need for isolation and purification of intermediate is allowed. The structures of obtained compounds were proved by modern methods of physical-chemical analysis (1H, 13C NMR, IR and MS spectroscopy).Forcitation:Stepanova E.V., Stepanov A.I. Unusual way of reaction of 3-amino-4-(5-chloromethyl-1,2,4-oxadiazole-3-yl)furazan with hydrazine. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 4. P. 26-32.      


2020 ◽  
Vol 21 (24) ◽  
pp. 9623
Author(s):  
Łukasz Szczukowski ◽  
Edward Krzyżak ◽  
Adrianna Zborowska ◽  
Patrycja Zając ◽  
Katarzyna Potyrak ◽  
...  

The long-term use of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in treatment of different chronic inflammatory disorders is strongly restricted by their serious gastrointestinal adverse effects. Therefore, there is still an urgent need to search for new, safe, and efficient anti-inflammatory agents. Previously, we have reported the Mannich base-type derivatives of pyrrolo[3,4-d]pyridazinone which strongly inhibit cyclooxygenase, have better affinity to COX-2 isoenzyme and exert promising anti-oxidant activity. These findings encouraged us to perform further optimization of that structure. Herein, we present the design, synthesis, molecular docking, spectroscopic, and biological studies of novel pyrrolo[3,4-d]pyridazinone derivatives bearing 4-aryl-1-(1-oxoethyl)piperazine pharmacophore 5a,b–6a,b. The new compounds were obtained via convenient, efficient, one-pot synthesis. According to in vitro evaluations, novel molecules exert no cytotoxicity and act as selective COX-2 inhibitors. These findings stay in good correlation with molecular modeling results, which additionally showed that investigated compounds take a position in the active site of COX-2 very similar to Meloxicam. Moreover, all derivatives reduce the increased level of reactive oxygen and nitrogen species and prevent DNA strand breaks caused by oxidative stress. Finally, performed spectroscopic and molecular docking studies demonstrated that new compound interactions with bovine serum albumin (BSA) are moderate, formation of complexes is in one-to-one ratio, and binding site II (subdomain IIIA) is favorable.


2018 ◽  
Vol 14 ◽  
pp. 2308-2312 ◽  
Author(s):  
Edwin Alfonzo ◽  
Jesse W L Mendoza ◽  
Aaron B Beeler

A one-pot synthesis of epoxides from commercially available benzyl alcohols and aldehydes is described. The reaction proceeds through in situ generation of sulfonium salts from benzyl alcohols and their subsequent deprotonation for use in Corey–Chaykovsky epoxidation of aldehydes. The generality of the method is exemplified by the synthesis of 34 epoxides that were made from an array of electronically and sterically varied alcohols and aldehydes.


Synlett ◽  
2018 ◽  
Vol 30 (02) ◽  
pp. 189-192 ◽  
Author(s):  
Yujiro Hoshino ◽  
Kiyoshi Honda ◽  
Kenta Tanaka ◽  
Mami Kishimoto ◽  
Naoya Ohtsuka ◽  
...  

A highly selective one-pot synthesis of polysubstituted isoflavanes has been developed. The reaction proceeds through the cycloaddition of methyl styryl ethers, derived from phenylacetaldehyde dimethyl acetals under acidic conditions, with electron-withdrawing ortho-quinone methides generated in situ. When phenylacetaldehyde dimethyl acetals were reacted with salicylaldehydes, the reaction proceeded smoothly to afford the corresponding isoflavanes stereoselectively in high yields and with excellent regioselectivities. The present reaction provides versatile access to functionalized isoflavanes, and constitutes a useful tool for the synthesis of biologically active molecules.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5285
Author(s):  
Xin Xie ◽  
Junyi Liu ◽  
Xiaowei Wang

Stimulator of interferon genes (STING) is an endoplasmic reticulum adaptor transmembrane protein that plays a pivotal role in innate immune system. STING agonists, such as endogenous cyclic dinucleotide (CDN) cyclic GMP-AMP (cGAMP), have been used in diverse clinical research for immunogenic tumor clearance, antiviral treatments and vaccine adjuvants. CDNs containing noncanonical mixed 3′-5′ and 2′-5′ phosphodiester linkages show higher potency in the activation of the STING pathway. In this study, a series of 2′3′-CDNs were designed and synthesized through a modified one-pot strategy. We then established a surface plasmon resonance (SPR)-based binding assay to quantify the binding affinities of synthesized CDNs for human STING, which requested a minuscule amount of sample without any pretreatment. Using this assay, we identified compound 8d (KD = 0.038 μM), a novel CDN that showed higher binding affinity with hSTING than cGAMP (KD = 0.543 μM). Cellular assays confirmed that 8d could trigger the expression of type I IFNs and other proinflammatory cytokines more robust than cGAMP. 8d also exhibited more resistant than cGAMP to enzymatic cleavage in vitro, indicating the successful improvement in drug availability. These findings provide guidelines for the design and structural optimization of CDNs as STING agonists.


Synthesis ◽  
2018 ◽  
Vol 51 (03) ◽  
pp. 713-729 ◽  
Author(s):  
Vitali Boitsov ◽  
Alexander Stepakov ◽  
Alexander Filatov ◽  
Nickolay Knyazev ◽  
Stanislav Shmakov ◽  
...  

A simple, efficient and atom-economic method has been developed for the synthesis of complex alkaloid-like compounds with spiro-fused indolo[2,1-b]quinazoline and cyclopropa[a]pyrrolizine or 3-azabicyclo[3.1.0]hexane moieties. We have found that one-pot, three-component 1,3-dipolar cycloaddition reactions allow the desired products to be obtained from various cyclopropene derivatives with tryptanthrin-derived azomethine ylides generated in situ, in good to high yields and excellent diastereoselectivity. The possibility of ylide generation was exemplified by using α-amino acids (l-proline, l-4-thiazolidincarboxylic acid) and simplest peptides (dipeptide Gly-Gly, tripeptide Gly-Gly-Gly). Quantum chemical investigations indicate that the reaction proceeds through the S-shaped azomethine ylide, the interaction of which with cyclopropenes proceeds via a less sterically hindered endo-transition state. The antitumor activity of some of spiro-tryptanthrin derivatives against erythroleukemia (K562), cervical carcinoma (HeLa) and colon carcinoma (CT26) cell lines was evaluated in vitro by MTS-assay.


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