ChemInform Abstract: Unexpected Domino Ring Closure: Highly Stereoselective Construction of a Tetracyclic Indole Alkaloid Ring System.

ChemInform ◽  
2009 ◽  
Vol 40 (13) ◽  
Author(s):  
Jian Xiao ◽  
Teck-Peng Loh
Keyword(s):  
Indole Alkaloid ◽  
Ring System ◽  
Ring Closure

Organophosphorus compounds. XX. Approaches to the synthesis of 2,3-Dihydro-1H-1,2-benzazaphospholes involving C-C and C-P ring closure

1984 ◽  
Vol 37 (5) ◽  
pp. 1009 ◽  
Author(s):  
DJ Collins ◽  
PF Drygala ◽  
JM Swan
Keyword(s):  
Organophosphorus Compounds ◽  
Heterocyclic Ring ◽  
Ring System ◽  
Ring Closure ◽  
Aluminium Chloride

Reaction of chloromethylphosphonic dichloride (9) with N-methylaniline gave N,N'-dimethyl-N,N'-diphenylchloromethylphosphonodiarnide (10) which upon treatment with aluminium chloride underwent intramolecular Friedel-Crafts alkylation to afford 1-methyl-2-(N'-methyl-N'-phenylamino)-2,3-dihydro-1N-l,2-benzazaphosphole 2-oxide(13a). Similarly, N-methyl-N-phenyl(ch1oromethy1)phenylphosphinamide (15) was cyclized to give 1-methyl-2-phenyl-2,3-dihydro-1H-1,2-benzazaphosphole2-oxide (1 3b). Some unsuccessful approaches to this heterocyclic ring system are also reported.

A general synthesis of 5,7-diaminoimidazo[4,5-b]pyridine ribosides ("2-amino-1-deazaadenosines") from 5-amino-4-imidazolecarboxamide riboside (AICA riboside)

1992 ◽  
Vol 70 (5) ◽  
pp. 1288-1295 ◽  
Author(s):  
John E. Francis ◽  
Michael A. Moskal
Keyword(s):  
Pyridine Ring ◽  
Sodium Hydride ◽  
Ring System ◽  
Ring Closure ◽  
Protecting Groups ◽  
Amino Group ◽  
Phosphoryl Chloride ◽  
Compound A ◽  
General Synthesis ◽  
Methyl Analog

A short general synthesis of 5-substituted 5,7-diaminoimidazo[4,5-b]pyridines from 5-amino-4-imidazolecarboxamide riboside (AICA riboside) was designed to prepare isosteres of substituted 2-aminoadenosines that are selective adenosine A2 receptor agonists. AICA riboside was converted to a hydroxyl-protected 5-amino-4-imidazolecarbonitrile riboside and reacted with an N,N-disubstituted acetamide in the presence of phosphoryl chloride. Sodium hydride treatment completed the ring closure and introduced the 7-amino group. The hydroxyl protecting groups were removed under standard conditions. N-Substitution of the acetamide by one benzyl moiety led to a 5-N-substituted derivative through hydrogenolysis whereas N,N-dibenzylacetamide led to the 5,7-diamino compound. A 6-methyl analog was obtained from an N,N-disubstituted propionamide. This synthesis may be adapted to other heterocyclic systems, as illustrated by the preparation of an example of the imidazo[4,5-b]pyrrolo[3,2-e]pyridine ring system.

Conolutinine, a hexacyclic indole alkaloid with a novel ring system incorporating a diazaspiro center and fused oxadiazepine–tetrahydrofuran rings

2009 ◽  
Vol 50 (7) ◽  
pp. 752-754 ◽  
Author(s):  
Kuan-Hon Lim ◽  
Tadahiro Etoh ◽  
Masahiko Hayashi ◽  
Kanki Komiyama ◽  
Toh-Seok Kam
Keyword(s):  
Indole Alkaloid ◽  
Ring System

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 and establishment of the absolute stereochemistry of (+)-mostueine. Addition of chiral nucleophiles to 3,4-dihydro-2-methyl-9-(p-toluenesulfonyl)-β-carbolinium iodide

1992 ◽  
Vol 70 (12) ◽  
pp. 2922-2928 ◽  
Author(s):  
Allan W. Rey ◽  
Walter A. Szarek ◽  
David B. MacLean
Keyword(s):  
Total Synthesis ◽  
Indole Alkaloid ◽  
Optical Purity ◽  
Ring System ◽  
Asymmetric Induction ◽  
Iminium Salt ◽  
High Optical Purity ◽  
The Absolute ◽  
Absolute Stereochemistry ◽  
Mediated Reduction

A highly convergent synthesis of the pentacyclic indole alkaloid (+)-mostueine (1) is described. The key step involved the coupling of the dianion derived from (1′S)-3-(1′-hydroxyethyl)-4-methylpyridine (4) with the iminium salt 3,4-dihydro-2-methyl-9-(p-toluenesulfonyl)-β-carbolinium iodide (3). Low asymmetric induction (15% de) at the C-1 position of the β-carboline ring system (C-3 of mostueine) was obtained. The nonfermenting baker's yeast-mediated reduction of 3-acetyl-4-methylpyridine provided the hydroxyethylpyridine component in acceptable yield (67%) and high optical purity (99.0% ee). This synthesis of 1 has established that the absolute stereochemistry of mostueine is (3S, 19R).

TRYPTAMINES, CARBOLINES, AND RELATED COMPOUNDS: PART IV. ATTEMPTED SYNTHESIS OF THE PHYSOSTIGMINE RING SYSTEM

1958 ◽  
Vol 36 (2) ◽  
pp. 354-357 ◽  
Author(s):  
R. A. Abramovitch
Keyword(s):  
Ring System ◽  
Ring Closure ◽  
Stable Form ◽  
Related Compounds

4-Methylpiperid-2,3-dione-3-phenylhydrazone failed to undergo ring closure under Fisher–cyclization conditions but rearranged to a more stable form of the phenylhydrazone. Cis–trans isomerism is suggested for the two forms.

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