Functionally Substituted Enamines as Building Blocks in Heterocyclic Synthesis: Reactivity of Glyoxal Diphenylhydrazone toward Electrophilic Reagents

2005 ◽  
Vol 2005 (11) ◽  
pp. 729-732 ◽  
Author(s):  
Huwaida M. E. Hassaneen ◽  
Tayseer A. Abdallah ◽  
Hamdi M. Hassaneen ◽  
Mohamed H. Elnagdi
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Benzoyl Chloride ◽  
Phosphorus Oxychloride ◽  
Aromatic Aldehydes ◽  
Building Blocks ◽  
Secondary Amines ◽  
Vilsmeier Reaction ◽  
Heterocyclic Synthesis ◽  
Electrophilic Reagents

Glyoxalbis(phenylhydrazone) 1a reacts with aromatic aldehydes and secondary amines to yield either propan-1,2-dialdiphenylhydrazones 2 or arylazopyrazoles 7 depending on the nature of utilised aldehyde. The reactivity of 1a with phosphorus oxychloride (POCl3) and dimethylformamide (DMF) (Vilsmeier reaction) afforded the cinnolin-3-carbaldehyde phenylhydrazone 11. Compound 1a afforded also the tribenzoyl derivative 16 on treatment with benzoyl chloride. Only the diacetyl derivative 17 was produced on refluxing 1a in acetic anhydride. The diphenylhydrazone 20 was produced on treatment of 19, prepared via coupling 18 with benzenediazonium chloride followed by phenylhydrazine. This cyclised into pyrazole 21 on reflux in acetic acid.

Alkyl Heteroaromatics as Building Blocks in Organic Synthesis: The Reactivity of Alkyl Azoles toward Electrophilic Reagents

1999 ◽  
Vol 54 (7) ◽  
pp. 923-928 ◽  
Author(s):  
I. S. Abdel Hafiz ◽  
A. A. Hassanien ◽  
A. M. Hussein
Keyword(s):  
Acetic Anhydride ◽  
Organic Synthesis ◽  
Ethyl Cyanoacetate ◽  
Aromatic Aldehydes ◽  
Building Blocks ◽  
Subsequent Treatment ◽  
Diazonium Salts ◽  
Phenyl Hydrazine ◽  
Electrophilic Reagents

Oxazolone (1) couples with aromatic diazonium salts to yield the arylhydrazones (3a-c). Compound 3 reacts with aniline to give aryl hydrazone (5). Compound 5 was also obtained via converting 1 into the imidazolone (4) and subsequent treatment of 4 with aromatic diazonium salts. Compounds 1 and 12 reacted with arylidenemalononitrile (6) to yield compounds 8 and 14 respectively. Also compounds 1, 12 condensed with an aromatic aldehydes to yield 11 and 17. Compounds 11, 17 reacted further with one molecule of malononitrile to give compounds 8 and 14, respectively. Compound 20 which was generated in situ by heating phenacylthiocyanate (19) in acetic anhydride on treatment with hydrazine hydrate or phenyl hydrazine gives 21 and 22 respectively. A lso 20 reacted with malononitrile or with ethyl cyanoacetate to give 23 and 24, respectively.

The Meisenheimer rearrangement in heterocyclic synthesis. II. Synthesis and X-ray crystal structure of a tetrahydro-1H-2,3-benzoxazocine and preparation of a hexahydro-2,3-benzoxazonine

1980 ◽  
Vol 33 (6) ◽  
pp. 1323 ◽  
Author(s):  
JB Bremner ◽  
EJ Browne ◽  
PE Davies ◽  
CLWAH Raston
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Acetic Acid ◽  
Crystal And Molecular Structure ◽  
Phosphorus Oxychloride ◽  
Crystallographic Analysis ◽  
Heterocyclic Synthesis ◽  
Reaction Conditions ◽  
X Ray ◽  
Heterocyclic Derivatives

The heterocyclic derivatives, 8,9-dimethoxy-3-methyl-1-phenyl-3,4,5,6- tetrahydro-1H-2,3-benzoxazocine(3a) and 9,10-dimethoxy-3-methyl-1- phenyl-1,3,4,5,6,7-hexahydro-2,3-benzoxazonine (3b),examples of two new ring systems, have been prepared by Meisenheimer rearrangement of the corresponding 2-benzazepine and 2-benzazocine N-oxide derivatives (2a) and (2b). The Bischler-Napieralski-type cyclization reaction was used in the preparation of the tertiary amine precursors of these N-oxides reaction conditions for the cyclization were critical and phosphorus oxychloride in refluxing butanenitrile was found to give the best yields of the seven- or eight-membered cyclic imine intermediates. Reductive cleavage of the benzoxazocine derivative (3a) with zinc in acetic acid followed by N-methylation gave the expected product, [2-{3- (dimethylamino)propyl}-4,5-di-methoxyphenyl]phenylmethanol (12). The crystal and molecular structure of (3a) has been determined by X-ray crystallographic analysis.

Enaminones as Building Blocks In Heterocyclic Synthesis: A New One Pot Synthesis of Polyfunctional Substituted Pyridines

2001 ◽  
Vol 56 (10) ◽  
pp. 1074-1078 ◽  
Author(s):  
Samia Michel Agamy ◽  
Mervat Mohammed Abdel-Khalik ◽  
Mona Hassan Mohamed ◽  
Mohammed Hilmy Elnagdi
Keyword(s):  
Acetic Acid ◽  
Double Bond ◽  
Aromatic Aldehyde ◽  
Michael Addition ◽  
Ammonium Acetate ◽  
Building Blocks ◽  
Heterocyclic Synthesis ◽  
One Pot ◽  
Active Methyl ◽  
Substituted Pyridines

Enaminones react with a variety of active methyl and methylene reagents in presence of ammonium acetate to yield functionally substituted pyridines in good yields. The reaction proceeded via initial Michael addition across the double bond followed by cyclization. The reaction of enaminone with aromatic aldehyde in acetic acid/ammonium acetate afforded the dihydropyridine that was oxidized to the corresponding pyridine.

scholarly journals Enaminonitrile as Building Block in Heterocyclic Synthesis: Synthesis of Novel 4H-Furo[2,3-d][1,3]oxazin-4-one and Furo[2,3-d]pyrimidin-4(3H)-one Derivatives

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Manal M. El-Shahawi ◽  
Ahmed K. El-Ziaty
Keyword(s):  
Acetic Anhydride ◽  
Building Block ◽  
Benzoyl Chloride ◽  
Heterocyclic Synthesis ◽  
Elemental Analyses ◽  
Nitrogen Nucleophiles

2-Amino-4,5-diphenylfuran-3-carbonitrile 1 was utilized as building block for the construction of new furo[2,3-d]pyrimidin-4(3H)-one derivative 2 and 4H-furo[2,3-d][1,3]oxazin-4-one derivative 3 via treatment with acetic anhydride and benzoyl chloride, respectively. The 4H-furo[2,3-d][1,3]oxazin-4-one derivative 3 was transformed into novel furo[2,3-d]pyrimidin-4(3H)-ones 4–8, tetrazolylfuran derivative 10, and furo[3,2-d]imadazolone derivative 11 via reaction with various nitrogen nucleophiles. The structure features of the synthesized compounds were established from their spectral and elemental analyses.

Synthesis, Characterization and Biological Studies of Some Bioactive Thiazolotriazole Derivatives

2010 ◽  
Vol 65 (12) ◽  
pp. 1509-1515 ◽  
Author(s):  
Manjunatha Kumsi ◽  
Boja Poojary ◽  
Prajwal Lourdes Lobo ◽  
Nalilu Suchetha Kumari ◽  
Anoop Chullikana
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Good Yield ◽  
Sodium Acetate ◽  
Aromatic Aldehydes ◽  
Antimicrobial Activities ◽  
One Pot ◽  
Biological Studies ◽  
Elemental Analyses

The key precursor rac-2-(4-isobutylphenyl)ethyl-1,2,4-triazole-5-thione (3) was synthesized in good yield from Ibuprofen (1). One-pot three-component reactions of 3 with 5-aryl-furan-2-carboxaldehydes/ substituted aromatic aldehydes and monochloroacetic acid in acetic acid in the presence of acetic anhydride and anhydrous sodium acetate afforded substituted thiazolo[3,2-b][1,2,4]triazole derivatives 4 and 5. The structures of the newly synthesized compounds were elucidated by elemental analyses and spectral data. The compounds were tested for their in-vitro antimicrobial activities.

Functionally Substituted Enamines as Building Blocks in Heterocyclic Synthesis: Reactivity of Glyoxal Diphenylhydrazone Toward Electrophilic Reagents.

ChemInform ◽  
2006 ◽  
Vol 37 (16) ◽  
Author(s):  
Huwaida M. E. Hassaneen ◽  
Tayseer A. Abdallah ◽  
Hamdi M. Hassaneen ◽  
Mohamed H. Elnagdi
Keyword(s):  
Building Blocks ◽  
Heterocyclic Synthesis ◽  
Electrophilic Reagents

scholarly journals The preparative synthetic approach to 4-(trifluoromethoxy)piperidine and 4-(trifluoromethoxymethyl)piperidine

2021 ◽  
Vol 19 (1(73)) ◽  
pp. 3-9
Author(s):  
Ivan G. Logvinenko ◽  
Violetta G. Dolovanyuk ◽  
Ivan S. Kondratov
Keyword(s):  
Mass Spectrometry ◽  
Benzoyl Chloride ◽  
Building Blocks ◽  
Secondary Amines ◽  
Synthetic Approach ◽  
Synthetic Strategy ◽  
Benzoyl Group ◽  
Two Stages ◽  
13C And 19F Nmr ◽  
Convenient Synthetic Approach

Aim. To develop a convenient synthetic approach for the preparation of multigram amounts of 4-(trifluoromethoxy)-piperidine and 4-(trifluoromethoxymethyl)piperidine – promising building blocks for medicinal chemistry.Results and discussion. 4-(Trifluoromethoxy)piperidine (8.4 g) and 4-(trifluoromethoxymethyl)piperidine (12.9 g) were synthesized in 5 stages starting from 4-hydroxypiperidine (the overall yield 40 %) and 4-(hydroxymethyl)piperidine (the overall yield 13.5 %), respectively.Experimental part. The first stage of the synthetic strategy was acylation of 4-hydroxypiperidine with benzoyl chloride. N-benzoyl-4-hydroxypiperidine obtained was transformed to N-benzoyl-4-(trifluoromethoxy)piperidine in two stages using the Hiyama method (the synthesis of the corresponding S-methyl xanthate with the subsequent desulfurization/fluorination using N-bromosuccinimide and Olah’s reagent). Then the N-benzoyl group was reduced to benzyl one, which was removed using 1-chloroethyl chloroformate. The similar approach was applied to the synthesis of 4-(trifluoromethoxymethyl)piperidine starting from 4-(hydroxymethyl)piperidine. The structure and composition of the compounds synthesized were confrmed by 1Н, 13C and 19F NMR spectroscopy,mass-spectrometry and elemental analysis.Conclusions. The synthetic approach developed is a convenient method for the multigram preparation of4-(trifluoromethoxy)piperidine and 4-(trifluoromethoxymethyl)piperidine and can be used for the synthesis of other secondary amines containing the CF3O-group.Key words: fluorination; trifluoromethoxy group; xanthate; piperidine; protection group

scholarly journals Synthesis and Characterization of Some New Benzimidazole Derivatives

2016 ◽  
Vol 13 (1) ◽  
pp. 82-88
Author(s):  
Baghdad Science Journal
Keyword(s):  
Acetic Acid ◽  
Mannich Base ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Secondary Amines ◽  
Synthesis And Characterization ◽  
Benzimidazole Derivatives ◽  
Schiff Base Derivatives ◽  
New Compounds

In this paper the new starting material 2-(5-chloro-1H-benzo[d]imidazole-2-yl) aniline (1) was synthesized by the condensation reaction of 4-chloro-o-phenylenediamine and anthranilic acid .The new Mannich base derivatives were synthesized using formaldehyde and different secondary amines to synthesize a new set of benzimidazole derivatives(2-5). Also, the new Schiff-base derivatives (6-10) were synthesized from the reaction of compound (1) with various aromatic aldehydes and the closure-ring was done successfully using mercapto acetic acid to get the new thiazolidine derivatives(11-12).These new compounds were characterized using some physical techniques like:FT-IR Spectra and 1HNMR Spectra.

γ-Oxo Carboxylic Acids in Heterocyclic Synthesis, III. Synthesis of Biologically Active 4-Benzylamino-6-(5,5-dioxodibenzothiophen- 2-yl)-2,3,4,5-tetrahydropyridazin-3-ones

2002 ◽  
Vol 57 (6) ◽  
pp. 668-676 ◽  
Author(s):  
Ashraf A. F. Wasfy ◽  
Mohamed M. H. Arief ◽  
Mahassen S. Amine ◽  
Shafey G. Donia ◽  
Aly A. Aly
Keyword(s):  
Hydrazine Hydrate ◽  
Sodium Azide ◽  
Aromatic Aldehydes ◽  
Biologically Active ◽  
Secondary Amines ◽  
Keto Acid ◽  
Heterocyclic Synthesis ◽  
Reaction Conditions ◽  
Carbon Nucleophiles ◽  
Pyrazolone Derivative

α-Benzylamino-β-(5,5-dioxodibenzothiophen-2-carbonyl)propionic acid (1) has been synthesized by treating the corresponding β-aroylacrylic acid with benzylamine in dry benzene. On treatment with hydrazine hydrate the keto acid 1 furnishes the corresponding pyridazinone derivative 2. The behaviour of 2 towards carbon electrophiles, namely, ethyl chloroacetate, acrylonitrile, formaldehyde and secondary amines (under Mannich reaction conditions), aromatic aldehydes and carbon nucleophiles, namely, POCl3/PCl3 and P2S5 has been investigated. The 3-chloropyridazine derivative 13 reacts with hydrazine hydrate to give the 3-hydrazino derivative 14. On treatment with ethyl acetoacetate and/or acetylacetone the hydrazine 14 undergoes cyclization to afford pyrazolone derivative 16 and 3-(3,5-dimethylpyrazol- 1-yl)pyridazine derivative 17, respectively. On reaction with acetylhydrazine in boiling butanol and/or sodium azide in DMF the 3-chloropyridazine derivative 13 affords the triazolo[4,3-b]pyridazine 18 and the tetrazolo[1,5-b]pyridazine 19, respectively. The anti-microbial activity of the synthesized derivatives has been investigated.

Fluorine-Containing Heterocycles: Part I. Synthesis of New 7-(2-thienyl)-9-Trifluoromethylpyrido[3′,2′:4,5]Thieno[3,2-d]Pyrimidines and Related Fused Tetracyclic Systems

2005 ◽  
Vol 2005 (3) ◽  
pp. 147-154 ◽  
Author(s):  
Etify A. Bakhite ◽  
Abdu E. Abdel-Rahman ◽  
Elham A. Al-Taifi
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Formic Acid ◽  
Hydrazine Hydrate ◽  
Methyl Iodide ◽  
Phosphorus Oxychloride ◽  
Diethyl Malonate ◽  
Triethyl Orthoformate ◽  
Dimroth Rearrangement ◽  
Ethyl Chloroacetate

3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carboxamide (3) and 2-carbonitrile analogue 5 were prepared by reaction of 3-cyano-6-(2-thienyl)-4-trifluoromethylpyridine-2(1H)-thione (1) with chloroacetamide or chloroacetonitrile respectively. Heating compound 3 with triethyl orthoformate led to the formation of pyridothienopyrimidinone derivative 6. Reaction of 6 with phosphorus oxychloride produced 4-chloropyrimidine derivative 7 which underwent some nucleophilic displacements upon treatment with thiourea, piperidine, morpholine or hydrazine hydrate to give the target 4-substituted pyridothienopyrimidines 8, 10a, 10b and 11 respectively. Reaction of compound 8 with methyl iodide or ethyl chloroacetate gave compounds 9a,b. The condensation of 3-amino-6-(2-thienyl)-4-trifluoromethyl-thieno[2,3-b]pyridine-2-carbonitrile (5) with triethyl orthoformate led to the formation of methanimidate derivative 21 which upon treatment with hydrazine hydrate gave the target 3-amino-3,4-dihydro-4-imino-7-(2-thienyl)-9-trifluoromethylpyrido[3′,2′:4,5] thieno[3,2-d]pyrimidine (22). The reactions of compounds 11 and 22 with some reagents namely; triethyl orthoformate, acetic anhydride, formic acid, acetic acid, acetylacetone benzaldehyde and/or diethyl malonate were carried out and their products were identified, in most cases as [1,2,4]triazolopyridothienopyrimidines via Dimroth rearrangement.

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