Name Reactions and Reagents in Organic Synthesis

Mundy, Bradford P.; Ellerd, Michael G.; Favaloro, Frank G.

doi:10.1002/9780471739876

Cited by 87 publications

(44 citation statements)

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“…We believe that the mechanism presented in Scheme 2 is a better mechanistic representation of Perkin's serendipitous reaction and should, if proven, supplant all current, published named reaction mechanisms. 20 All that we lack is the direct spectroscopic evidence for the proposed, four membered b-lactone.…”

Section: Discussionmentioning

confidence: 99%

Not quite the last word on the Perkin reaction

et al. 2014

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a b s t r a c tMicrowave irradiation does not accelerate the rate of the Perkin reaction carried out under normal atmospheric pressure. Water is an essential yet catalytic reactant for the Perkin reaction to occur. Containment of the Perkin reaction in a sealed vessel improves the yield. Two pressure increases are observed during a 4 h reaction time. An induction period is seen in the Perkin reaction when sodium acetate is used as a base. A re-appraisal of the reaction mechanism is proposed on the basis of these observations. The use of PFA Ò reaction vessels enables the Perkin reaction to occur under aqueous conditions for around 80 reactions/vessel.

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Section: Discussionmentioning

confidence: 99%

Not quite the last word on the Perkin reaction

et al. 2014

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“…Figure 7 shows the classic Baeyer-Villiger oxidation reaction. 29 We have demonstrated the operation of this mechanism using isotopically labeled oxygen ( 18 O) and water as reactants in separate experiments and then examining the products for the presence of the labels as shown in Figure 9.…”

Section: Reactions and Mechanismsmentioning

confidence: 99%

The Use Of N-Methylpyrrolidone as a Cosolvent and Oxidant in Pharmaceutical Stress Testing

Reynolds

Galvani

Hicks

et al. 2012

Journal of Pharmaceutical Sciences

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“…Chemoselective reduction of the azide group by iron powder in the presence of ammonium chloride [33] furnished o-amino aldehydes 5a,b as pale-yellow crystalline solids in excellent yield. The Friedländer condensation of o-amino aldehydes such as 5-aminopyrazole-4-carbaldehydes with ketones is described to take place either with strong bases or acids as catalysts; in special cases the ring closure can be observed without a catalyst at higher temperatures (e.g., under microwave irradiation) [34][35][36][37]. Having 5-aminopyrazolo-4-carbaldehyde in our hand, like others [4,[38][39][40][41] we have applied the Friedländer condensation reaction with active methylene compounds to get pyrazolo [3,4-b]pyridines.…”

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confidence: 99%

Synthesis and antibacterial activity of some novel pyrazolopyridine derivatives

Panda

Karmakar

Jena

2011

Chem Heterocycl Comp

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Eight pyrazolo [3,4-b]pyridine derivatives have been synthesized by Friedländer condensation of 5-aminopyrazole-4-carbaldehyde with active methylene compounds in basic medium. These compounds have been screened for their antibacterial activity against two Gram-negative and two Gram-positive bacterium. Pyrazolopyridines having the carboxamide group at the 5-position showed moderate to good activity against P. aeruginosa, E. coli, S. pneumoniae, and B. cereus.The evolution of antibacterial resistance in bacterial strains against the currently available antibacterial agents is an increasing concern in recent years. For instance, Gram-positive bacterial pathogen such as Staphylococcus aureus is resistant to Methicillin, and Streptococcus pneumoniae and Enterococci are resistant to Penicillin and Vancomycin, respectively [1]. On the other hand, Gram-negative bacteria such as H. influenza and M. catarrahalis are resistant to β-lactams, quinolones, and macrolides [2]. In order to overcome the threat of widespread multidrug resistance in Gram-positive as well as Gram-negative bacterial strains, there is an ongoing demand for new antibacterials.Pyrazolo [3,4-b]pyridines as aza-analogs of indazoles [3] have long served as attractive targets in organic synthesis due to their excellent antibacterial activity [4]. Moreover, pyrazolo[3,4-b]pyridines also exhibit other promising biological activities, including anxiolytic (e.g., Tracazolate) [5], dopamine D3-receptor antagonist and partial agonist [6], dopamine D4 antagonist [7], adenosine A1-receptor antagonist [8,9], antiherpetic [10], antiinflammatory [11], and antiallergic [12] properties. The methods so far reported for the synthesis of pyrazolopyridines include: i) the annelation of the pyrazole ring onto the suitably substituted pyridine ring [13][14][15][16][17][18][19], and ii) the annelation of the pyridine ring onto the appropriately substituted pyrazole ring [13,[20][21][22][23][24][25][26][27][28][29][30]. As part of our ongoing program [31] for the development of new antibacterials, we are particularly interested in the synthesis of pyrazolo [3,4-b]pyridines by the latter method. Like others, our strategy involves the Friedländer condensation of 5-aminopyrazoles with active methylene compounds as the key step. In this paper we report the full details of our efforts on the synthesis of some novel pyrazolo[3,4-b]pyridine derivatives and their antimicrobial profile against two Gram-positive and two Gram-negative bacterium species.

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Name Reactions and Reagents in Organic Synthesis

Cited by 87 publications

References 0 publications

Not quite the last word on the Perkin reaction

Not quite the last word on the Perkin reaction

The Use Of N-Methylpyrrolidone as a Cosolvent and Oxidant in Pharmaceutical Stress Testing

Synthesis and antibacterial activity of some novel pyrazolopyridine derivatives

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