scholarly journals Synthetic route towards 1,2,3,4-tetrahydroquinoxaline/piperidine combined tricyclic ring system

2021 ◽  
pp. 68-68
Author(s):  
Mihajlo Krunic ◽  
Ivana Jevtic ◽  
Jelena Penjisevic ◽  
Sladjana Kostic-Rajacic
Keyword(s):  
Heterocyclic System ◽  
Structural Features ◽  
Ring System ◽  
Synthetic Route ◽  
Amino Groups ◽  
Hofmann Rearrangement

The synthetic route toward novel tricyclic, nitrogen-containing system is disclosed. Three novel compounds possessing structural features of 1,2,3,4-tetrahydroquinoxaline and decahydropyrido[3,4-b]pyrazine are synthesized starting from readily available precursors in six or seven steps, of which the last three or four steps respectfully are diastereoselective. Key reaction steps include N-acylation, Hofmann rearrangement and ring-closing Buchwald-Hartwig reaction. Compounds trans-8, cis-12 and trans-12 are synthesized in order to prove that this novel, tricyclic system can be functionalized with various groups. Synthetic significance of this heterocyclic system lies in the possibility for the orthogonal functionalization of three different amino groups, allowing fine structural tuning.

scholarly journals Studies on the Enantioselective Synthesis of E-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 428
Author(s):  
Nihan Yayik ◽  
Maria Pérez ◽  
Elies Molins ◽  
Joan Bosch ◽  
Mercedes Amat
Keyword(s):  
Ring System ◽  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Hydroxymethyl Group ◽  
Hydride Reduction ◽  
Lactam Carbonyl ◽  
Key Steps ◽  
Oxindole Alkaloids

A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a cis H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an E-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the E-ethylidene substituent by acetylation at the α-position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(S)-geissoschizol oxindole has been prepared.

Efficient Synthesis of Novel N-[4-Methyl-3-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)thiazol-2(3H)-ylidene]benzamide Hybrid Ring System as Potential Antibacterial Agents

2021 ◽  
Vol 17 ◽  
Author(s):  
Hummera Rafique ◽  
Aamer Saeed ◽  
Muhammad Naseem ◽  
Tauqeer Riaz ◽  
Fouzia Perveen ◽  
...  
Keyword(s):  
Bacterial Resistance ◽  
Antioxidant Activities ◽  
Antibacterial Properties ◽  
Antibacterial Activities ◽  
Structural Features ◽  
Ring System ◽  
Biologically Active ◽  
Thiazole Ring ◽  
Spectroscopic Techniques ◽  
Hybrid Ring

Background: Heterocyclic compounds display versatile biological applications, so the aim of this paper was to prepare biologically important heterocycles with enhanced bacterial resistance and to evaluate for their various structural features that are responsible for their biological properties. Objective: The objective was to synthesize bacterial resistance compounds with enhanced antibacterial properties. Method: Ester moiety containing thiazole ring was converted into its hydrazide derivatives. These heterocyclic derivatives were cyclized into another ring oxadiazole; hence a hybrid ring system of two biologically active rings was prepared. Result: All the synthesized compounds were characterized by spectroscopic techniques and were screened for their antibacterial potential; they possess significant antibacterial activities. Conclusion: New hybrid heterocyclic ring systems were synthesized by cyclization of hydrazide derivatives by adopting two step strategy in good yields. All the synthesized compounds were evaluated for their antioxidant activities; they showed moderate to significant activities. QSAR and Molecular docking studies were performed to determine the mode of interaction. Experimental and computational data is in accordance with the determined antibacterial activities.

A New Synthetic Route for 3,4-Disubstituted Tetrahydrothiophenes and a New Fragmentation of Their Ring System

Heterocycles ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 313 ◽  
Author(s):  
Kazuo Achiwa ◽  
Masahiro Aono ◽  
Yoshiyasu Terao
Keyword(s):  
Ring System ◽  
Synthetic Route

A Synthetic Route to the Morphan Ring System from Norbornadiene. The Synthesis of the 6,7-Pyridazinoannelated Morphan

Heterocycles ◽  
1984 ◽  
Vol 21 (2) ◽  
pp. 656 ◽  
Author(s):  
Hiroo Inoue ◽  
Toshiki Origuchi ◽  
Katsumi Umano
Keyword(s):  
Ring System ◽  
Synthetic Route

scholarly journals Synthesis of Novel N-Heterocyclic Compounds Containing 1,2,3-Triazole Ring System via Domino, “Click” and RDA Reactions

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 772 ◽  
Author(s):  
Márta Palkó ◽  
Mohamed El Haimer ◽  
Zsanett Kormányos ◽  
Ferenc Fülöp
Keyword(s):  
Heterocyclic Compounds ◽  
Click Reaction ◽  
Triazole Ring ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Diels Alder ◽  
Ring Closure ◽  
Synthetic Route ◽  
13C Nuclear Magnetic Resonance ◽  
Nmr Methods

An uncomplicated, high-yielding synthetic route has been developed to constitute complicated heterocycles, applying domino, click and retro-Diels–Alder (RDA) reaction sequences. Starting from 2-aminocarboxamides, a new set of isoindolo[2,1-a]quinazolinones was synthesized with domino ring closure. A click reaction was performed to create the 1,2,3-triazole heterocyclic ring, followed by an RDA reaction resulting in dihydropyrimido[2,1-a]isoindole-2,6-diones. The absolute configuration, concluded by the norbornene structure that served as a chiral source, remained constant throughout the transformations. The structure of the synthesized compounds was examined by 1H and 13C Nuclear Magnetic Resonance (NMR) methods.

Total Synthesis of (–)-Aristoquinoline via an Intramolecular Nitrilium Ion Cyclization

Synthesis ◽  
2021 ◽  
Author(s):  
Keith P. Reber ◽  
Priyansh D. Gujarati
Keyword(s):  
Total Synthesis ◽  
Natural Product ◽  
Building Block ◽  
Spectroscopic Properties ◽  
Ring System ◽  
Synthetic Route ◽  
Enantioselective Total Synthesis ◽  
Key Steps

AbstractThe enantioselective total synthesis of the alkaloid aristoquinoline has been achieved in seven steps and 26% overall yield. A new preparation of the useful synthetic building block (–)-α-terpinyl amine was also developed in order to avoid stoichiometric mercury reagents or azide-containing intermediates. Key steps in the optimized synthetic route include an intramolecular nitrilium ion cyclization to form the characteristic azabicyclo[3.3.1]nonane ring system and a dia­stereoselective reduction of the resulting imine mixture to afford the natural product. An isomer of aristoquinoline containing an exocyclic alkene was also obtained and found to exhibit unusual chromatographic and spectroscopic properties.

Photosystem II Inhibition by 3-Acyl-5-(l-aminoalkylidene)-4-hydroxy- 2H -pyran-2,6(3H)-dione Derivatives

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1127-1132 ◽  
Author(s):  
Koichi Yoneyama ◽  
Makoto Konnai ◽  
Tadao Asami ◽  
Nobutaka Takahashi ◽  
Shigeo Yoshida
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
High Activity ◽  
Photosynthetic Electron Transport ◽  
Structural Features ◽  
Pyran Ring ◽  
Amino Groups

3-Acyl-5-(1-aminoalkylidene)-4-hydroxy-2 H- pyran-2,6(3 H)-dione derivatives carrying lipophilic amino groups were found to be highly potent inhibitors of photosynthetic electron transport, and both the acyl and the aminoalkylidene groups on the pyran ring appeared to be indispensable for high activity. The structural features needed for activity in the 3-acyl-5- (l-am inoalkylidene)-4-hydroxy -2 H-pyran -2 ,6 (3 H)-dione derivatives were very similar to those for 3 -(l-aminoalkylidene)-2H-pyran-2,4(3H)-diones, except for the acyl group in the former compounds. Thermoluminescence measurements indicated that the 3-acyl-5- (1-aminoalkylidene)-4 -hydroxy -2H-pyran -2 ,6 (3 H )-dione derivatives bind to the D 1 protein in a manner similar to that of DCMU .

Sign in / Sign up

Export Citation Format

Share Document