ChemInform Abstract: A SYNTHETIC ROUTE TO THE MORPHAN RING SYSTEM BY SKELETAL TRANSFORMATION OF NORBORNADIENE

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.

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

Heterocycles ◽

10.3987/r-1986-02-0313 ◽

1986 ◽

Vol 24 (2) ◽

pp. 313 ◽

Cited By ~ 7

Author(s):

Kazuo Achiwa ◽

Masahiro Aono ◽

Yoshiyasu Terao

Keyword(s):

Ring System ◽

Synthetic Route

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

Heterocycles ◽

10.3987/s-1984-02-0656 ◽

1984 ◽

Vol 21 (2) ◽

pp. 656 ◽

Cited By ~ 1

Author(s):

Hiroo Inoue ◽

Toshiki Origuchi ◽

Katsumi Umano

Keyword(s):

Ring System ◽

Synthetic Route

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Exploration of a proposed biomimetic synthetic route to plumarellide. Development of a facile transannular Diels–Alder reaction from a macrocyclic enedione leading to a new 5,6,7-tricyclic ring system

Tetrahedron Letters ◽

10.1016/j.tetlet.2010.10.154 ◽

2011 ◽

Vol 52 (17) ◽

pp. 2088-2092 ◽

Cited By ~ 27

Author(s):

Yi Li ◽

Gerald Pattenden

Keyword(s):

Alder Reaction ◽

Ring System ◽

Diels Alder ◽

Synthetic Route ◽

Diels Alder Reaction

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

Journal of the Serbian Chemical Society ◽

10.2298/jsc210416068k ◽

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.

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

Molecules ◽

10.3390/molecules24040772 ◽

2019 ◽

Vol 24 (4) ◽

pp. 772 ◽

Cited By ~ 1

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.

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

Synthesis ◽

10.1055/s-0041-1737276 ◽

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.

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