Synthesis and biological activities of novel bis‐heterocyclic pyrrodiazole derivatives

He, Feng-Qi; Liu, Xinghai; Wang, Baolei; Li, Zhengming

doi:10.1002/hc.20369

Cited by 23 publications

(16 citation statements)

References 11 publications

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“…For example, in the pyrazole ring system C (4) is the most electron rich carbon, thus, H (4) in is expected to appear at higher field at δ 6.31 ppm. On the other hand, H (5) is linked to the carbon attached to nitrogen atom and thus it's deshielded to appear in the region δ 7.5 -8.5 ppm [26][27][28]. The 1 H NMR spectra of isolated reaction products revealed, in each case, a singlet signal at δ 8.5 ppm which indicates the presence of the pyrazole H (5) rather than H (4) in the structure of the isolated products.…”

Section: Resultsmentioning

confidence: 96%

Reactivity of 1-methylisoquinoline synthesis of pyrazolyl triazoloisoquinoline and thia-diazolyl isoquinoline derivatives

Hassaneen¹,

Mohammed²

2011

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The reaction of 1-methylisoquinoline 1 with hydrazonoyl halides 2 in ethanol in the presence of chitosan under microwave irradiation affords triazoloisoquinoline 4. Product 4 reacts with dimethylformamide-dimethylacetal to give enaminones 7 which react with hydrazonoyl halides to give pyrazolyl triazoloisoquinoline 13. Also, 1-methylisoquinoline 1 reacts with arylisothiocyanate to give thioanilide 15 which reacts with hydrazonoyl halides to give the corresponding thiadiazolyl isoquinoline derivatives 20, 24.

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Section: Resultsmentioning

confidence: 96%

Reactivity of 1-methylisoquinoline synthesis of pyrazolyl triazoloisoquinoline and thia-diazolyl isoquinoline derivatives

Hassaneen¹,

Mohammed²

2011

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“…The latter reaction products were assumed to be formed via initial 1,3-dipolar cycloaddition of the nitrilimines 5a-m to the activated double bond in compound 3 to afford the non-isolable cycloadducts 6a-m which undergoes loss of dimethylamine yielding the final pyrazole derivatives 7a-m. [44][45][46] The 1 H NMR spectra of the isolated products 7a-m revealed, in each case a singlet signal in the region of 8.40-8.72 ppm which indicates the presence of the pyrazole H-5 rather than H-4. This conclusion was further confirmed chemically by the reaction compounds 7a,d,g with hydrazine hydrate, to afford pyrazolo[3,4-d]pyridazines 8a-c, respectively (Scheme 2).…”

Section: Methodsmentioning

confidence: 97%

Enaminones as Building Blocks in Heterocyclic Preparations: Synthesis of Novel Pyrazoles, Pyrazolo[3,4-d]pyridazines, Pyrazolo[1,5-a]pyrimidines, Pyrido[2,3-d]pyrimidines Linked to Imidazo[2,1-b]thiazole System

Gomha¹,

Abdel‐Aziz²

2012

HETEROCYCLES

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The unreported 2-[E-3-(N,N-dimethylamino)acryloyl]-3-methyl-5,6diphenylimidazo[2,1-b]thiazole 3 was prepared via the reaction of 2-acetyl-3methyl-5,6-diphenylimidazo[2,1-b]thiazole 2 with dimethylformamide dimethyl acetal (DMF-DMA). Enaminone 3 underwent regioselective 1,3-dipolar cycloaddition with nitrilimines 5a-f, to afford the corresponding pyrazoles 7a-f.The reaction of 7a,d,g with hydrazine hydrate, afforded the pyrazolo[3,4d]pyridazines 8a-c, respectively. Enaminone 3 also reacted with a hydrazines, hydroxylamine hydrochloride, 5-aminopyrazole 11, 6-aminothiouracil 15 and hippuric acid 22. The structures of the newly synthesized compounds were confirmed by spectral data and elemental analyses.Enaminones are poly-dentate reagents that have been utilized extensively in this decade as building blocks in organic synthesis. 1-9 Furthermore, many enaminones were found to exhibit several biological activities as antitumor, antibacterial and anticonvulsant agents. 10,11 On the other hand, imidazoles possess important biological, pharmacological and therapeutic activities, 12,13 where midazoles are present in compounds that have antiasthmatic, 16 anti-inflammatory, 17 antiulcerative, 18 antithrombotic, 19 fungicidal 20 and herbicidal activities. 21 Furthermore, some imidazo[2,1b]thiazoles were active against various cancer cell lines. 22 Much interest has also been focused on the chemistry and anticonvulsant, analgesic, 23 antibacterial 24 and antisecretory 25 activities displayed by HETEROCYCLES, Vol. 85, No. 9, 2012 2291 1 2 3 Scheme 1Treatment of the enaminone 3 with nitrilimines 5a-m, [liberated in situ from the corresponding hydrazonyl halides 4a-m, respectively, with triethylamine in refluxing toluene], it afforded the 3,4disubstituted-1H-pyrazoles 7a-m, respectively (Schemes 2). The latter reaction products were assumed to be formed via initial 1,3-dipolar cycloaddition of the nitrilimines 5a-m to the activated double bond in compound 3 to afford the non-isolable cycloadducts 6a-m which undergoes loss of dimethylamine yielding the final pyrazole derivatives 7a-m. [44][45][46] The 1 H NMR spectra of the isolated products 7a-m revealed, in each case a singlet signal in the region of 8.40-8.72 ppm which indicates the presence of the pyrazole H-5 rather than H-4. This conclusion was further confirmed chemically by the reaction compounds 7a,d,g with hydrazine hydrate, to afford pyrazolo[3,4-d]pyridazines 8a-c, respectively (Scheme 2).

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“…Typically the signal of H-5 usually appears at δ 8.66-8.69 33 whereas that of H-4 appears at δ 5.81-5.89. 34,35 Thus, the formation of 8 rather than 7 indicates that the studied reaction of 4 with 2 is regiospecific. To account for the formation of 8, it is suggested that the reaction of 4 with 2 proceeds via 1,3-dipolar cycloaddition of the nitrilimine, derived from 2c, to the activated double bond in the enaminone 4 to give the respective cycloadduct 6 which in turn undergoes in situ elimination of dimethylamine to afford 8 as the end product.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, reactions and antitumor activity of new β-aminovinyl 3-pyrazolyl ketones

Shawali¹,

Farghaly²,

Al-Dahshoury³

2010

Arkivoc

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A new series of enaminones 4a-e was prepared and their reaction with the hydrazonoyl chloride 2c gave 3,4'-bis(pyrazolyl)ketones 8a-d. Hydrazinolysis of 8 proved to be site selective as it yielded the respective 4-(pyrazol-3-yl)-2H-pyrazolo[3,4-d]pyridazines 9. The results of screening of the antitumor activity of enaminones 4a-e against human breast cell line MCF-7 revealed that all such compounds exhibited lower activity in relation to the reference drug Doxorubicin and the activity of the enaminone having electron-accepting substituent is more than that having electron donating substituent.

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Synthesis and biological activities of novel bis‐heterocyclic pyrrodiazole derivatives

Cited by 23 publications

References 11 publications

Reactivity of 1-methylisoquinoline synthesis of pyrazolyl triazoloisoquinoline and thia-diazolyl isoquinoline derivatives

Reactivity of 1-methylisoquinoline synthesis of pyrazolyl triazoloisoquinoline and thia-diazolyl isoquinoline derivatives

Enaminones as Building Blocks in Heterocyclic Preparations: Synthesis of Novel Pyrazoles, Pyrazolo[3,4-d]pyridazines, Pyrazolo[1,5-a]pyrimidines, Pyrido[2,3-d]pyrimidines Linked to Imidazo[2,1-b]thiazole System

Synthesis, reactions and antitumor activity of new β-aminovinyl 3-pyrazolyl ketones

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