Quinoline Alkaloids: Synthesis of Pyrano[2,3-<i>b</i>]quinolines, Khaplofoline, Lunacrine, and Demethoxylunacrine

Sekar, M.; Prasad, K. J. Rajendra

doi:10.1021/np970005i

Cited by 47 publications

(14 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, the spectrum revealed the disappearance of characteristic absorption of both pyrone and carboxylate C═O groups. 1 H NMR spectrum of compound 18 presented chemical shifts due to four aromatic protons at δ 7.41 to 8.58 and a highly down-field shifted singlet peak for the proton at position-7. The latter proton appeared at abnormal chemical shift owing to anisotropic effect of its neighboring C═O of fused pyridine and also additional deshielding gained by many nitrile functions.…”

Section: Resultsmentioning

confidence: 99%

“…This leading trend announced a large congress of novel substituted heterocyclic compounds. Pyranoquinolines alkaloids are fused heterocyclic systems, which have massive existence in nature and are associated with important biological activities . In general, pyranoquinolines are mostly bioactive molecules, particularly pyrano[3,2‐ c ]quinolines revealed various potent medicinal properties .…”

Section: Introductionmentioning

confidence: 99%

“…Pyranoquinolines alkaloids are fused heterocyclic systems, which have massive existence in nature and are associated with important biological activities. [1,2] In general, pyranoquinolines are mostly bioactive molecules, particularly pyrano [3,2-c]quinolines revealed various potent medicinal properties. [3,4] For instance, some pyrano [3,2-c]quinolines proved to be interesting antiviral agent against HIV, [5] potent topoisomerase TOP-IIβ and breast tumor inhibitors, [6] anticancer and anti-inflammatory agents, [7] and antimicrobial agents.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Substituted quinolinones. 31. Some new pyrano[3,2‐c]quinoline‐3‐carboxamides and their antioxidant activity

Othman

Hassan

Abass

2019

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

1‐Ethyl‐4‐hydroxy‐2‐oxo‐1,2‐dihydroquinoline‐3‐carbaldehyde (1) was annulated using malonic acid and/or its ethyl ester to furnish pyrano[3,2‐c]quinoline‐3‐carboxylic acid 2 and its ester 3. Interconversions between acid 2 and ester 3 were successfully carried out. The anticipated pyrano[3,2‐c]quinoline‐3‐carboxamides 5–12 were conveniently attained via condensation of ester 3 with the proper amine. Surprisingly, treatment of ester 3 with dimethylformamide (DMF) in acidic media led to the carboxamide 5. All attempts to convert ester 3 to its corresponding acid hydrazides by interaction with the proper hydrazine derivative led to formation of pyrazolidinediones 15 and 17. Ester 3 underwent cyclo‐condensation with malononitrile dimer affording pyrido[3′,4′:5,6]pyrano[3,2‐c]quinoline derivative 18. The new compounds revealed significant antioxidant effect, which suggests that most of them are possible potent antioxidant agents.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Substituted quinolinones. 31. Some new pyrano[3,2‐c]quinoline‐3‐carboxamides and their antioxidant activity

Othman

Hassan

Abass

2019

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

show abstract

“…b), and findersine (Fig. c) are the few examples of natural products . The nitrogen containing linomide (Fig.…”

Section: Introductionmentioning

confidence: 99%

Sulfamic Acid Catalyzed Atom Economic, Eco‐friendly Synthesis of Novel 7‐(Aryl)‐10‐thioxo‐7,9,10,11‐tetrahedro‐6H‐pyrimido‐[5′4′:5,6]pyrano[3,2‐c]quinoline‐6,8(5H)‐dione and its Derivatives

Jadhav

Patil

Kumbhar

et al. 2017

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

A series of novel 7‐(3‐chloro‐phenyl)‐10‐thioxo‐7,9,10,11‐tetrahedro‐6H‐pyrimido‐[5′4′:5,6] pyrano[3,2‐c]quinoline‐6,8(5H)‐dione derivatives have been synthesized through the multi‐component condensation of aromatic aldehydes, barbituric acid, and 2,4‐dihydroxy quinoline, using heterogeneous sulfamic acid catalyst in water‐ethanol (4:1) solvent system under reflux condition. The present protocol is endowed with charming description such as green synthetic procedure, short reaction time, easy work‐up procedure, and excellent yield and high atom economy of pyranoquinoline derivatives. In this study, sulfamic acid is used as a heterogeneous catalyst that is easily recoverable and recyclable. The proposed multi‐component reaction has been studied with detail mechanism and spectroscopic data. This is one of the potential greener synthetic approaches to build up the series of pyranoquinoline heterocycles.

show abstract

“…They have interesting pharmacological activities like antihistamine, antibiotic, CNS, anti cancer, antiinflam m atory and antimicrobial prop erties [1][2][3][4][5][6][7][8][9][10][11][12][13]. An extensive survey of the literature showed that a variety of routes had been devel oped for the preparation of quinoline derivatives [14,15].…”

mentioning

confidence: 99%

A Facile Synthesis of Naphthyl-Quinolyl Ethanes and Chromenyl-Quinolyl Ethanes

Sekar

Prasad

1999

Zeitschrift Für Naturforschung B

Self Cite

View full text Add to dashboard Cite

2,4-Dihydroxyquinoline, 1-Tetralone, Chromanone, 2,4-D ichloro-3-[l'-(l-chloro-naphth-2-yl)ethyl]quinoline, 2,4-D ichloro-3-[l'-(4-chloro-2-methyl-chromen-3-y 1 )ethyl]quinolineThe reaction of alkaline 2,4-dihydroxyquinoline 1 and 1-tetralone 2 in 2% sodium hydrox ide solution with vinyl acetate afforded a brown solid 3, which on treatment with phospho rous oxychloride yielded 2,4-dichloro-3-[l'-(l-chloro-naphth-2-yl)ethyl]quinoline (4). The same reaction of 1 and chromanone 7 with vinyl acetate afforded 2,4-dichloro-3-[l'-(4-chloro-2-m ethyl-chromen-3-yl)ethyl]quinoline (9).Quinoline derivatives occur quite frequently in Nature. They have interesting pharmacological activities like antihistamine, antibiotic, CNS, anti cancer, antiinflam m atory and antimicrobial prop erties [1][2][3][4][5][6][7][8][9][10][11][12][13]. An extensive survey of the literature showed that a variety of routes had been devel oped for the preparation of quinoline derivatives [14,15]. We wish to report the vinylation reaction technique to the mixture of 1 -tetralone or chro manone with 2,4-dihydroxyquinoline for the pro ductive synthesis of hitherto unknown quinoline derivatives.The reaction of alkaline 2,4-dihydroxyquinoline (la) and 1 -tetralone (2) with vinyl acetate at room tem perature yielded a brown solid. It was insolu ble in all solvents. On treatm ent with POCl3 it af forded a single product 4, melting at 125-126 °C. The IR-spectrum of 4 docum ented the presence of a C=C absorption in the 1600 cm -1 region. The 'H NM R spectrum in CDC13 showed a three proton doublet at 6 1.75, assigned to methyl protons with J = 9.0 Hz, one proton quartet centered at d 5.10, assigned to a m ethine proton adjacent to methyl protons with J = 9.0 Hz. A ten proton aromatic portion appeared at d 7.25-8.30 ppm. The em er gence of molecular ion peak at m/e 385 (M+) and the micro analysis C, 65.48%; H, 3.68% and N, 3.62% were consistent with the molecular formula C2 iH 14N Cl3. On the basis of analytical and * Reprint requests to Dr. K. J. Rajendra Prasad.Fax: 091-422-422387. E-mail: Chemist@bharathi.ernet.in spectral values, the structure 4 was proposed for the compound and named as 2,4-dichloro-3-[l'-(lchloro-naphth-2-yl)ethyl]quinoline (4a) (Scheme). The above reaction might proceed by condensa tion of vinyl acetate with 2,4-dihydroxy-quinoline (1 ) with the concomitant loss of acetic acid to yield the transient 4-hydroxy-3-vinylquinoline 5a. A n other possibility would be condensation of 2,4-dihydroxyquinoline (1 ) with acetaldehyde (formed by hydrolysis of vinyl acetate) affording 5b di rectly. The carbanionic Michael type addition of pre-existing 1-tetralone to isomeric 5b might af ford product 3. Finally, compound 3, on treatm ent with POCI3, could yield the corresponding chloro derivative 4 (Scheme).The same reaction was extended to an other de rivative of 2,4-dihydroxy quinoline (lb ) with 1-tetralone to yield derivative 4b (Scheme).The same experim entation technique was ex tended to 2,4-dihydroxyquinoline (la) with chromanones (7) with vinyl...

show abstract

Quinoline Alkaloids: Synthesis of Pyrano[2,3-b]quinolines, Khaplofoline, Lunacrine, and Demethoxylunacrine

Cited by 47 publications

References 15 publications

Substituted quinolinones. 31. Some new pyrano[3,2‐c]quinoline‐3‐carboxamides and their antioxidant activity

Substituted quinolinones. 31. Some new pyrano[3,2‐c]quinoline‐3‐carboxamides and their antioxidant activity

Sulfamic Acid Catalyzed Atom Economic, Eco‐friendly Synthesis of Novel 7‐(Aryl)‐10‐thioxo‐7,9,10,11‐tetrahedro‐6H‐pyrimido‐[5′4′:5,6]pyrano[3,2‐c]quinoline‐6,8(5H)‐dione and its Derivatives

A Facile Synthesis of Naphthyl-Quinolyl Ethanes and Chromenyl-Quinolyl Ethanes

Contact Info

Product

Resources

About