Access to Imidazo[1,2-<i>a</i>]pyridines via Annulation of α-Keto Vinyl Azides and 2-Aminopyridines

Adiyala, Praveen Reddy; Mani, Ganesh Kumar; Nanubolu, Jagadeesh Babu; Shekar, Kunta Chandra; Maurya, Ram Awatar

doi:10.1021/acs.orglett.5b02124

Cited by 65 publications

(17 citation statements)

References 48 publications

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“…A possible mechanism for the synthesis of substituted quinazolines was proposed in Scheme according to the recent literature reports ,. Initially, phenacyl azides loses nitrogen (‐N 2 ) under Cu(OAc) 2 /Et 3 N catalytic system to give copper chelated imine 4 .…”

Section: Resultsmentioning

confidence: 99%

Copper-Catalysed Tandem Synthesis of Substituted Quinazolines from Phenacyl Azides and O -Carbonyl Anilines

et al. 2017

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An efficient protocol for the synthesis of substituted quinazolines from 2-aminoacetophenones/benzophenones and phenacyl azides using copper catalysed base mediated system is developed. This method utilizes phenacyl azides for generation of imine precursors for transimination with o-carbonyl anilines followed by condensation to yield quinazolines. This mild catalytic system is efficient in construction of two CÀN bonds in a single operation. The reaction proceeded well to give a series of 22 examples of quinazolines with good to excellent yields and wide range of functional group tolerance.

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Section: Resultsmentioning

confidence: 99%

Copper-Catalysed Tandem Synthesis of Substituted Quinazolines from Phenacyl Azides and O -Carbonyl Anilines

et al. 2017

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“…In this paper, we described a targeted reaction for the synthesis of a series of novel poly functionalized 6-amino-pyrazolo[1,5-a]pyrimidines 3 by Michael-addition-cyclization of α-azidochalcones 1 with 3-aminopyrazoles 2 (Scheme 1). It should be also noted that α-azidochalcones 1 have been applied over the last decade to prepare several valuable nitrogen containing skeletons [64][65][66][67][68][69][70][71][72][73][74][75] . To probe the generality of this strategy, various derivatives of both starting materials were applied under the appropriate reaction condition to afford a large library of corresponding 6-amino-pyrazolo[1,5-a]pyrimidines 3 in 65-92% yields.…”

Section: Chemistrymentioning

confidence: 99%

An efficient and targeted synthetic approach towards new highly substituted 6-amino-pyrazolo[1,5-a]pyrimidines with α-glucosidase inhibitory activity

Peytam

Adib

Shourgeshty

et al. 2020

Sci Rep

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In an attempt to find novel α-glucosidase inhibitors, an efficient, straightforward reaction to synthesize a library of fully substituted 6-amino-pyrazolo[1,5-a]pyrimidines 3 has been investigated. Heating a mixture of α-azidochalcones 1 and 3-aminopyrazoles 2 under the mild condition afforded desired compounds with a large substrate scope in good to excellent yields. All obtained products were evaluated as α-glucosidase inhibitors and exhibited excellent potency with IC 50 values ranging from 15.2 ± 0.4 µM to 201.3 ± 4.2 µM. Among them, compound 3d was around 50-fold more potent than acarbose (IC 50 = 750.0 ± 1.5 µM) as standard inhibitor. Regarding product structures, kinetic study and molecular docking were carried out for two of the most potent ones. Recently, the world health organization (WHO) has identified the diabetes mellitus (DM) as a critical health challenge in the 21st century. The prevalence of diabetes has been increasing at alarming rate over the past three decades. This metabolic disorder, characterized by chronic hyperglycemia, leads to further severe damages like abnormally great thrust, excessive appetite, overweigh, blindness, excessive urination, cardiovascular complications, as well as renal and neurodegenerative diseases 1-6. There are three main diabetes types among which type 2 or non-insulin dependent (T2DM) is the most common one, mainly treated by controlling the digestive enzyme activities such as α-glucosidase 7-9. α-Glucosidase, found in the brush-border surface membrane of intestinal cells, plays catalyzing role in the carbohydrate digestion process by which the postprandial blood glucose levels increases. Preventing the glucose release in the bloodstream, the α-glucosidase inhibitors control T2DM 10. Additionally, this enzyme has a pivotal role in the biosynthesis of glycoprotein, therefore, its inhibitors have possessed anticancer, antitumor, antiviral, and immunoregulatory properties 11-15. Acrabose, miglitol, voglibose, and deoxynojirimycin have clinically been used to restrict the α-glucosidase activity 16. Considering the side effects and absorption problems associated with these drugs, new scaffolds should be synthesized and evaluated by medicinal chemists to extend the library of compounds 17-25. Pyrazoles are common structural motif in numerous drugs 26 and biologically active compounds showing activities such as anti-cancer 27,28 , anti-inflammatory 29 , anti-hypertensive 30 , cannabinoid receptor antagonist 31 , dopaminergic receptor antagonist 32 , and α-glucosidase inhibitors 33. Pyrazoles have been used to synthesize

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“…Current approaches for the synthesis of imidazo[1,2‐ a ]pyridine structures include cyclocondensations of 2‐aminopyridines to acetophenones , 1,3‐dicarbonyl compounds , α,β‐unsaturated ketones , α‐halocarbonyl compounds , propargylic alcohols , or nitroolefins and also one‐pot, multicomponent reaction of 2‐aminopyridines with aryl glyoxals and cyclic 1,3‐dicarbonyls . In addition, the coupling of aldehydes with 2‐aminopyridines and alkynes or isonitriles (Gröbcke–Blackburn–Bienaymé reaction) in one‐pot protocol was found to be a suitable process for the preparation of imidazo[1,2‐ a ]pyridine compounds .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of 4‐Hydroxy‐3‐(2‐arylimidazo[1,2‐a]pyridin‐3‐yl)quinolin‐2(1H)‐ones in the Presence of DABCO as an Efficient Organocatalyst

Khalafy

Marjani

Khalillou

2019

Journal of Heterocyclic Chem

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The one‐pot, three‐component, synthesis of a new series of 4‐hydroxy‐3‐(2‐arylimidazo[1,2‐a]pyridin‐3‐yl)quinolin‐2(1H)‐ones in the presence of DABCO as a catalyst has been achieved using aryl glyoxal monohydrates, quinoline‐2,4(1H,3H)‐dione, and 2‐aminopyridine in H2O/EtOH under reflux conditions. The cheapness of organocatalyst, simple workup, operational simplicity, regioselectivity, and high yields are some advantages of this protocol.

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Access to Imidazo[1,2-a]pyridines via Annulation of α-Keto Vinyl Azides and 2-Aminopyridines

Cited by 65 publications

References 48 publications

Copper-Catalysed Tandem Synthesis of Substituted Quinazolines from Phenacyl Azides and O -Carbonyl Anilines

Copper-Catalysed Tandem Synthesis of Substituted Quinazolines from Phenacyl Azides and O -Carbonyl Anilines

An efficient and targeted synthetic approach towards new highly substituted 6-amino-pyrazolo[1,5-a]pyrimidines with α-glucosidase inhibitory activity

Synthesis of 4‐Hydroxy‐3‐(2‐arylimidazo[1,2‐a]pyridin‐3‐yl)quinolin‐2(1H)‐ones in the Presence of DABCO as an Efficient Organocatalyst

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