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.

Succinopyoverdins - a New Variety of the Pyoverdin Chromophore

2000 ◽  
Vol 55 (3-4) ◽  
pp. 146-152 ◽  
Author(s):  
Christof Lenz ◽  
Cordula Amann ◽  
Gernot Briskot ◽  
Kambiz Taraz ◽  
Herbert Budzikiewicz
Keyword(s):  
Structure Elucidation ◽  
Condensation Product ◽  
Ring System ◽  
Peptide Chain ◽  
New Variety ◽  
Pseudomonas Spp ◽  
Related Compounds

Abstract Pseudomonas spp. of the fluorescent group produce siderophores (so-called pyoverdins) consisting of a peptide chain attached to a pyrimidoquinoline ring system which is derived from a condensation product of L-Dab and D-Tyr. Commonly several related compounds are found to accompany the pyoverdins having the same peptide chain, but differing in the heterocyclic part. The structure elucidation of a new variety (succinopyoverdin) is described here.

Synthesis of Vinca Alkaloids and Related Compounds, Part LXXXIX. Some UnexpectedReactions of Compounds Containing the D-Seco-aspidospermane Ring System

Heterocycles ◽  
1998 ◽  
Vol 47 (1) ◽  
pp. 205 ◽  
Author(s):  
István Greiner ◽  
György Kalaus ◽  
Imre Juhász ◽  
Kinga Steinhauser ◽  
Mária Kajtár-Peredy ◽  
...  
Keyword(s):  
Ring System ◽  
Vinca Alkaloids ◽  
Related Compounds

Pyrimidine Derivatives and Related Compounds, V Synthesis of Some Isoxazolo [2,3-a] pyrimidines. A New Ring System

1977 ◽  
Vol 32 (3) ◽  
pp. 311-314 ◽  
Author(s):  
Mohamed Hilmy Elnagdi ◽  
Ezzat Mohamed Kandeel ◽  
Kamal Usef Sadek
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Ethyl Acetoacetate ◽  
Pyrimidine Derivative ◽  
Ring System ◽  
The Other ◽  
Acid Mixture ◽  
Pyrimidine Derivatives ◽  
Benzoyl Isothiocyanates ◽  
Related Compounds

3-Amino-5-phenyl-4-phenylazoisoxazole (1) reacts with ethyl acetoacetate to yield the corresponding ethyl isoxazolylaminocrotonate derivative (2) which could be thermally cyclized into the isoxazolopyrimidine derivative (4). On the other hand, condensation of 1 with ethoxymethylenemalononitrile has resulted in the formation of the aminoethylene derivative (5).Compound 1 reacted with acrylonitrile to yield the isoxazolo[2,3-a]pyrimidine derivative (6). The latter was converted into the corresponding exo derivative (8) by the action of acetic acid-hydrochloric acid mixture.Compound 1 also reacted with methoxycarbonyl-, ethoxycarbomyl- and benzoyl isothiocyanates to yield the isoxazolylthioureas (10a, b) and (11), respectively. The reaction of 2 with acetic acid-hydrochloric acid and with phenylhydrazine is reported.

N,N-Dialkyl-N′-Chlorosulfonyl Chloroformamidines in Heterocyclic Synthesis. Part XIV. Synthesis and Reactivity of the New Benzo[4,5]imidazo[1,2-b][1,2,6]thiadiazine Ring System

2018 ◽  
Vol 71 (1) ◽  
pp. 58 ◽  
Author(s):  
Dylan Innes ◽  
Michael V. Perkins ◽  
Andris J. Liepa ◽  
Craig L. Francis
Keyword(s):  
Medicinal Chemistry ◽  
Ring System ◽  
Heterocyclic Synthesis ◽  
Alkyl Derivatives ◽  
Regioselective Reactions ◽  
Novel Scaffold ◽  
Derivatives Of ◽  
Related Compounds

N,N-Dialkyl-N′-chlorosulfonyl chloroformamidines 1 underwent regioselective reactions with the 1,3-NCC bis-nucleophilic 1H-benzimidazole-2-acetonitriles 4 and related compounds to produce benzo[4,5]imidazo[1,2-b][1,2,6]thiadiazine dioxides 6, 9, 12, and 14, representatives of a new ring system. Reaction of dichlorides 1 with trifluoroacetyl derivative 16 afforded benzo[4,5]imidazo[1,2-c]pyrimidines 19 and 20. An N-acyl and some N-alkyl derivatives of benzimidazo-thiadiazines 6 were prepared to demonstrate the potential of this new ring system as a novel scaffold for synthetic and medicinal chemistry applications. Treatment of the 4-cyano-5-methyl-benzimidazo-thiadiazine 26c with LiAlH4 resulted in an unexpected and remarkable conversion of the nitrile to give the 4,5-dimethyl-benzimidazo-thiadiazine 29.

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.

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