Pyrimidine Derivatives and Related Compounds. VIII [1]. Routes for the Synthesis of 3,5‐Diaminopyrazoles, 2‐Aminopyrazolo[1,5‐a]pyrimidines and 5‐Aminopyrazolo[1,5‐a]pyrimidines

Elnagdi, Mohamed H.; Kandeel, E. M.; Zayed, E. M.; Kandil, Z. E.

doi:10.1002/prac.19783200405

Cited by 14 publications

(4 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…22 Thus, the attempted closure of a pyridine ring in com pounds 9a,b in acetic anhydride failed. This objective was achieved by using strong acid agents for activation of the indole C=O group.…”

Section: Methodsmentioning

confidence: 98%

2-[(3,5-Diamino-1H-pyrazol-4-yl)methylidene]-1,2-dihydro-3H-indol-3-ones: Synthesis and properties

et al. 2009

View full text Add to dashboard Cite

Reactions of 3 acetoxy 2 (2,2 dicyanovinyl)indole with hydrazine hydrate and methyl and phenylhydrazines afforded new indolin 3 one derivatives, namely, 2 [(3,5 diaminopyrazol 4 yl)methylidene]indolin 3 ones. Reactions of the compounds obtained with acetic anhydride and DMF and DMAA dimethyl acetals were studied. Cyclization of 2 [(3,5 diamino 1H pyrazol 4 yl)methylidene] 1,2 dihydro 3H indolinone gave 3 amino 1,5 dihydropyrazolo [4´,3´:5,6]pyrido[3,2 b]indole, a representative of a novel heterocyclic system. Key words: 3 acetoxy 2 (2,2 dicyanovinyl)indole, hydrazines, 2 [(3,5 diamino 1H pyrazol 4 yl)methylidene]indolin 3 ones, acetylation, X ray diffraction analysis, DMF and DMAA dimethyl acetals, cyclization, pyrazolo[4´,3´:5,6]pyrido[3,2 b]indole.

show abstract

Section: Methodsmentioning

confidence: 98%

2-[(3,5-Diamino-1H-pyrazol-4-yl)methylidene]-1,2-dihydro-3H-indol-3-ones: Synthesis and properties

et al. 2009

View full text Add to dashboard Cite

show abstract

“…Noteworthy, some authors believed (no evidence has been provided) that the endocyclic NH group is the most nucleophilic center in these compounds, although the experimental results (Al-Shiekh et al, 2004;Al-Omran and El-Khair, 2006;Dawood et al, 2005;Ege and Gilbert, 1979a;Ege et al, 1984;Elagamey et al, 1986;Elnagdi et al, 1976;1981;El-Ghandour Ahmed Hafez et al, 1992;Joshi et al, 1983;Kočevar et al, 1976) showed that such compounds could be successfully diazotized at the cost of the exocyclic NH 2 group which is consistent with the fundamentals of chemistry (Scheme 1).…”

Section: Relative Nucleophilicity Of the Amino And Imino Groupsmentioning

confidence: 99%

“…That is involved in the endocyclic N-1 nitrogen (Scheme 18). Elnagdi et al (1978) reported that 3,5-diaminopyrazole (47) reacted with acrylonitrile in refluxing aqueous pyridine to afford the corresponding 3,5-diamino-1-β-cyanoethyl pyrazole (Scheme 19).…”

Section: Relative Nucleophilicity Of Nh 2 Groupmentioning

confidence: 99%

“…Also, Elnagdi et al (1975) reported that reaction of the 5-aminopyrazole derivatives (57 a,b ) with ethyl benzoylacetate, in refluxing AcOH afforded the corresponding pyrazolo [1,5-a] Elnagdi et al (1978) consistent with the abovementioned results reported that when 3,5-diaminopyrazole (60) was heated with EAA in WB (in the absence of solvent), the corresponding pyrazolo [1,5-a]pyrimidine derivative (61) was obtained rather than the regio-isomer (62) (Scheme 24). Structure of the regio-isomer (61) was proved (Elnagdi et al, 1975b) by 1 H NMR and independent synthesis of ( 61) by decoupling of the phenylazo group from the previously prepared 2-amino-6,7dihydro-5-methyl-7-oxo-3-phenylazopyrazolo [1,5-a]pyrimidine (63) (Scheme 25).…”

Section: Reactions Of 3(5)-aminopyrazoles With 13-dicarbonyl Compoundsmentioning

confidence: 99%

See 1 more Smart Citation

Believes versus evidence-based regio-orientation in the structure assignment of pyrazolo[1,5-a]pyrimidines

2019

Japs

View full text Add to dashboard Cite

This review aims to focus and highlight the regio-orientation and regioselectivity of the reactions of 3(5)-aminopyrazoles with 1,3-bielectrophilic reagents that lead to the formation of pyrazolo [1,5-a]pyrimidines. To clarify the significance of regio-orientation, reactions of 3( 5)-aminopyrazoles with symmetric 1,3-bielectrophilic reagents such as acetylacetone and malononitrile are also included. The comparable nucleophilicity of the exocyclic NH 2 group and endocyclic NH in 3( 5)-aminopyrazoles is considered as it causes literature controversy associated with regio-orientation of the substituents on the pyrimidine ring of pyrazolo[1,5-a]pyrimidine when unsymmetrical 1,3-bielectrophilic reagent reacts with 3(5)-aminopyrazole. To the best of our knowledge, this review would be the first collective and confined report to the regio-orientation of pyrazolo [1,5-a]pyrimidines.

show abstract

Reactions with Heterocyclic Amidines, XI. Syntheses of New 2‐Aminopyrazolo[1,5—a]pyrimidines and 2‐Amino[1,5‐c]‐as‐triazines

Kandeel

Baghos

Mohareb

et al. 1983

Archiv der Pharmazie

View full text Add to dashboard Cite

Several new aminopyrazolo [ l,S-u]pyrimidines were synthesised by condensation of 33-diami-no4-(ethoxycarbonyl)pyrazoIe (1) with b-bifunctional reagents. The azo analogues of pyrazolo [l,5-u]pyrimidines, i. e. pyrazolo[l,4-c]-ar-triazines, were synthesised by coupling of diazotized 1 with agents containing active hydrogen. Reaktionen mit heteroqLliscaen Amidinen, ll. M i t t . : Syntheae e w e r nener Aminopyrrzolo[l,S-n]pyrhnicUn-Derivate und 2 -A m i n o [ l , S -c ] -~-t eEinige neue Aminopyrazolo[ 1,5-a]pyrimidin-Derivate wurden durch Umsetzung von 3,5-Diami- no-4-ethoxycarbonyl-pyrazol(l) mit p-bifunktionellen Reagenzien synthetisiert . Die Azoanalogen Pyrazolo[l,S-c]-as-tri~ne wurden durch Umsetzung von diazotiertem 1 mit Reagenzien mit aktivem Wasserstoff hergestellt.Schistosomiasis is considered to be one of the most difficult diseases to treat"). Accordingly considerable attention has been directed toward development of chemotherapeutic agents. Recently Sengu at a l ' ) have reported that certain pyrazolo[ 1 ,5-u]pyrimidines have considerable antischistosomal activity. 0365-6233/lWM84713 S U2.50/0 0 Verlae Chemie GmbH, Weinheim 1983 714 Kandeel, Baghos, Mohareb and ElnagdiArch. Pharm.

show abstract

Pyrimidine Derivatives and Related Compounds. VIII [1]. Routes for the Synthesis of 3,5‐Diaminopyrazoles, 2‐Aminopyrazolo[1,5‐a]pyrimidines and 5‐Aminopyrazolo[1,5‐a]pyrimidines

Cited by 14 publications

References 15 publications

2-[(3,5-Diamino-1H-pyrazol-4-yl)methylidene]-1,2-dihydro-3H-indol-3-ones: Synthesis and properties

2-[(3,5-Diamino-1H-pyrazol-4-yl)methylidene]-1,2-dihydro-3H-indol-3-ones: Synthesis and properties

Believes versus evidence-based regio-orientation in the structure assignment of pyrazolo[1,5-a]pyrimidines

Reactions with Heterocyclic Amidines, XI. Syntheses of New 2‐Aminopyrazolo[1,5—a]pyrimidines and 2‐Amino[1,5‐c]‐as‐triazines

Contact Info

Product

Resources

About