Substituent-Oriented Synthesis of Substituted Pyrazoles/Chromeno[3,2-c]pyrazoles via Sequential Reactions of Chromones/3-Chlorochromones and Tosylhydrazones

2019 ◽  
Vol 84 (9) ◽  
pp. 5913-5921 ◽  
Author(s):  
Tianzi Dai ◽  
Qunyi Li ◽  
Xiaofei Zhang ◽  
Chunhao Yang
Keyword(s):  
Substituted Pyrazoles ◽  
Sequential Reactions

Carbon Chain Growth by Sequential Reactions of CO and CO2 with a Transition Metal Carbonyl Complex

2018 ◽  
Author(s):  
Richard Kong ◽  
Mark Crimmin
Keyword(s):  
Transition Metal ◽  
Metal Carbonyl ◽  
Carbon Chain ◽  
Chain Growth ◽  
Carbonyl Complex ◽  
Fischer Tropsch ◽  
Carbon Chains ◽  
Sequential Coupling ◽  
Energy Economy ◽  
Sequential Reactions

<i>The formation of carbon chains by the coupling of COx (X = 1 or 2) units on transition metals is a fundamental step relevant to Fischer-Tropsch catalysis. Fischer-Tropsch catalysis produces energy dense liquid hydrocarbons from synthesis gas (CO and H2) and has been a mainstay of the energy economy since its discovery nearly a century ago. Despite detailed studies aimed at elucidating the steps of catalysis, experimental evidence for chain growth (Cn to Cn+1 ; n > 2) from the reaction of CO with metal complexes is unprecedented. In this paper, we show that carbon chains can be grown from sequential reactions of CO or CO2 with a transition metal carbonyl complex. By exploiting the cooperative effect of transition and main group metals, we document the first example of chain propagation from sequential coupling of CO units (C1 to C3 to C4), along with the first example of incorporation of CO2 into the growing carbon chain.</i><br>

SYNTHESIS OF NOVEL SUBSTITUTED PYRAZOLES AND ISOXAZOLES CONTAINING 1, 4-BENZODIOXANE SULFONYL MOIETY

2020 ◽  
Vol 13 (03) ◽  
pp. 1959-1963
Author(s):  
Sandhya Chhakra ◽  
G. S. Malhotra ◽  
S. Singh ◽  
S. S. Chauhan
Keyword(s):  
Substituted Pyrazoles

Synthesis and Antibacterial Screening of Some Pyrazole Derivatives Catalyzed by Cetyltrimethylammoniumbromide (CTAB)

2020 ◽  
Vol 17 ◽  
Author(s):  
Ravi Bansal ◽  
Pradeep K. Soni ◽  
Neha Gupta ◽  
Sameer S. Bhagyawant ◽  
Anand K. Halve
Keyword(s):  
Hydrazine Hydrate ◽  
Ethyl Acetoacetate ◽  
Aromatic Aldehydes ◽  
Pyrazole Derivatives ◽  
Phenyl Hydrazine ◽  
One Pot ◽  
Antibacterial Screening ◽  
Water As Solvent ◽  
Substituted Pyrazoles ◽  
Sulfinic Esters

Aims: In this article we have developed an eco-friendly one-pot multi-component reaction methodology was employed for the green synthesis of functionalized pyrazole derivatives viz cyclo-condensation of aromatic aldehydes, ethyl acetoacetate and phenyl hydrazine and/or hydrazine hydrate in the presence of cetyltrimethylammoniumbromide (CTAB) at 90°C temperature in aqueous medium. Method: In the present protocol we developed a green method for the synthesis of functionalized pyrazole derivatives through one-pot, multi-component cyclo-condensation of aromatic aldehydes, phenyl hydrazine or hydrazine hydrate and ethyl acetoacetate using cetyltrimethylammoniumbromide (CTAB) as a catalyst in water as solvent. Our methodology confers advantages such as short reaction time, atom economy, purification of product without using column chromatographic and hazardous solvent. The reaction is being catalyzed by cetyltrimethylammoniumbromide (CTAB) and thus products are formed under the green reaction conditions. Results: Initially the reaction of benzaldehyde and phenylhydrazine with ethyl acetoacetate was carried out in water at room temperature in the absence of the catalyst; no product was obtained after 24 h (Table 1 entry 1). When the reaction was carried out using L-proline as catalyst in ethanol at 70°C the yield of product was 20. Conclusion: This research not only provides a green and efficient method for the synthesis of sulfinic esters but also shows new applications of electrochemistry in organic synthesis. We consider that this green and efficient synthetic protocol used to prepare sulfinic esters will have good applications in future. In conclusion, we have developed successfully a green and efficient one-pot multi-component methodology for the synthesis of substituted pyrazoles using CTAB as a catalyst in water as solvent with excellent yields. Purifications of compounds were achieved without the use of traditional chromatographic procedures. This methodology has advantages of operational simplicity, clean reaction profiles and relatively broad scope which make it more attractive for the diversity oriented synthesis of these heterocyclic libraries. In this methodology we suggest the further alternative possibility for formation of substituted pyrazoles. The compound 7h can be used as an anticancer drug in pharma industry.

ChemInform Abstract: SYNTHESIS AND NEUROPHARMACOLOGICAL ACTIVITY OF 3(5)-SUBSTITUTED PYRAZOLES

1978 ◽  
Vol 9 (33) ◽  
Author(s):  
A. N. NIKOL'SKAYA ◽  
A. N. VOLKOV ◽  
E. P. LEVANOVA ◽  
K. A. VOLKOVA ◽  
S. E. METKALOVA ◽  
...  
Keyword(s):  
Neuropharmacological Activity ◽  
Substituted Pyrazoles

Time-on-stream behavior of sequential reactions

1989 ◽  
Vol 28 (12) ◽  
pp. 1743-1748 ◽  
Author(s):  
Ming Chow ◽  
Gary B. McVicker
Keyword(s):  
Sequential Reactions

Efficient Fluoride-Mediated Synthesis of 5-Alkyl Amino- and Ether-Substituted Pyrazoles

ChemInform ◽  
2006 ◽  
Vol 37 (3) ◽  
Author(s):  
Andrei Shavnya ◽  
Subas M. Sakya ◽  
Martha L. Minich ◽  
Bryson Rast ◽  
Kristin Lundy DeMello ◽  
...  
Keyword(s):  
Substituted Pyrazoles
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