Strained heterocyclic systems. IV. 1,2-Dihydrocyclobuta[b]quinoline and derivatives

Markgraf, J. Hodge; Katt, Robert J.; Scott, William L.; Shefrin, Russell N.

doi:10.1021/jo01264a081

Cited by 29 publications

(6 citation statements)

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“…1.23 Quinoxaline (7) 548 1.03" 2,3-Diphenyl quinoxaline (8) 564 0.85 Acenaphtho[1,2-6]quinoxaline (9) 573 0.72 Benzo [3,4] cyciobuta [ 1,[2][3][4][5][6] quinoxaline (3) 5818 0.62 Dibenzo[a,c]phenazine (10) 607 0.30 " Duplicate runs, ±2 mV, at 25°unless otherwise stated. 6 At 30°.…”

Section: Resultsmentioning

confidence: 99%

Strained heterocyclic systems. VI. Basicities of some quinoxalines

Markgraf¹,

Katt²

1972

J. Org. Chem.

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The basicities of a series of 2,3-disubstituted quinoxalines were determined by potentiometric titration in acetic anhydride. A decrease in basicity was observed for those compounds containing a fused, strained ring adjacent to the heteroatoms. Such an effect was consistent with previous interpretations based on orbital rehybridization. In conjunction with the present study, J (13C-H) values were determined for the benzylic protons of acenaphthene and pyracene.

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Section: Resultsmentioning

confidence: 99%

Strained heterocyclic systems. VI. Basicities of some quinoxalines

Markgraf¹,

Katt²

1972

J. Org. Chem.

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“…Markgraf and co-workers have synthesized 251 and its derivatives by base-catalyzed condensation of cyclobutanone 250 with o -aminobenzaldehyde ( eq29). , Wilk et al also reported a synthesis of 251 but in only 6% yield …”

Section: H Miscellaneous Routes To Cyclobutarenesmentioning

confidence: 99%

Cyclobutarenes and Related Compounds

2003

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A general method for the synthesis of cyclobutarenes involves 1,4-elimination from adjacent benzylic positions, followed by ring closure of the resulting o-quinodimethane. The earliest report in which an o-quinodimethane was implicated was the reaction of R,R,R′,R′-tetrabromo-o-xylene (4) with iodide to give the 1,2-dibromocyclobutarene 6, via o-quinodimethane 5. Treatment of 6 with NaI in acetone gave diiodide 7, which on catalytic reduction gave 1 (Scheme 1). [15][16][17] Cava and co-workers confirmed that 5 was an intermediate by trapping experiments using sev-eral dienophiles. 18 A similar procedure has been used to prepare 1,2-diphenylcyclobutarene. 19 Heterocyclic analogues may also be prepared by the 1,4-elimination of halogen from suitable precursors. Compounds 9 and 11 have been synthesized from 8 and 10, respectively, as illustrated in Scheme 2. 20 A variation of the method involves the conversion of R-alkyl-R-bromosulfones into cyclobutarenes using tetrabutylammonium fluoride (TBAF) in acetonitrile at 20-25 °C to effect the elimination. 21 The desired cyclobutarene is often accompanied by olefinic side products, as illustrated in the preparation of cyclobutarene 13, which is accompanied by 14 (eq 1) (Table 1). Anil K. Sadana was born in Panipat, India. He did his M.Sc (1990) and M. Phil (1992) from Kurukshetra University, India. He obtained his Ph.D. degree in 1999 under the guidance of Prof. Om Prakash. His Ph.D. work focused on the utility of hypervalentiodine reagents in the synthesis of heterocyclic compounds. He then joined Prof. W. E. Billups lab as postdoctoral research associate in 2000. He is presently working on small ring compounds and carbon nanotubes. Rajesh Kumar Saini was born in 1966 in Ambala, India. He received his masters degree in 1989 and his Ph.D. in 1996 from Kurukshetra University, India. After his doctorate he moved to the United States for his postdoctoral studies. After a brief stay at Sam Houston State University he joined Rice University, where he is working as a Research Scientist in the laboratories of Prof. W. E. Billups and Prof. Richard E. Smalley. His research has concentrated on small ring compound and the development of carbon nanotube chemistry. W. E. Billups was born in 1939 in Huntington, West Virginia. He received his B.S. in Chemistry Degree from Marshall University in 1961. This was followed by a period in industry after which he entered the graduate school of the Pennsylvania State University in 1968 and received the Ph.D. in 1970. He then joined the chemistry department at Rice University. He served as the Department Chair from July 1985 until December 1991. His research interests are divided among the areas of small-ring compounds, reactive intermediates, chemistry of free metal atoms and more recently fullerene and carbon nanotube chemistry.

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“…Annelation reaction with heterocyclic aminoaldehydes provides synthetic entry into heterocyclic systems fused to a pyridine or pyrimidine (44)(45)(46)(47) nucleus by condensation reaction. o-Aminoaldehyde has fascinating potential, remarkable versatility and utility for the annelation of heterocyclic ring structures to synthesize various heterocycles (48)(49)(50)(51)(52)(53). Known 2-aminoquinoline-3-carbaldehyde (o-aminoaldehyde) 1 has been synthesized by a novel method reported in our previous communication (42).…”

Section: Resultsmentioning

confidence: 99%

Effects of homogeneous media, binary mixtures and microheterogeneous media on the fluorescence and fluorescence probe properties of some benzo[b][1,8]naphthyridiens with HSA and BSA

Shelar¹,

Rote²,

Patil³

et al. 2011

Luminescence

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A rapid and efficient method for the synthesis of various poly-substituted benzo[b][1,8]naphthyridines in high yield has been developed via the Friedländer condensation of 2-aminoquinoline-3-carbaldehyde 1 with various alicyclic ketones in a base catalyst (aq. potassium hydroxide). A series of benzo[b][1,8]naphthyridines branched with various side-chains and substituents were prepared with the aim of being investigated as a fluorescent agents. Electronic absorption and fluorescence properties of some representative benzonaphthyridines (3d, 5b and 21f) in homogeneous organic solvents, dioxane-water binary mixtures and in the microheterogeneous media (sodium dodecyl sulphate (SDS), cetyl trimethyl ammonium bromide (CTAB) and Triton-X100 micelles) have been examined. A linear correlation between solvent polarity and fluorescence properties was observed. Further, the interaction of these benzonaphthyridines (3d, 5b and 21f) with human serum albumin (HSA) and bovine serum albumin (BSA) in phosphate buffer have been examined by UV-vis absorption and fluorescence spectroscopy. The fluorescence intensity of 3d, 5b and 21f increases with the increasing HSA and BSA concentration. These benzonaphthyridines also quench the 345 nm fluorescence of BSA in phosphate buffer (λ(ex) 280 nm). These compounds have potential for use as neutral and hydrophobic fluorescence probes for examining the microenvironments in proteins, polymers, micelles, etc.

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Strained heterocyclic systems. IV. 1,2-Dihydrocyclobuta[b]quinoline and derivatives

Cited by 29 publications

References 1 publication

Strained heterocyclic systems. VI. Basicities of some quinoxalines

Strained heterocyclic systems. VI. Basicities of some quinoxalines

Cyclobutarenes and Related Compounds

Effects of homogeneous media, binary mixtures and microheterogeneous media on the fluorescence and fluorescence probe properties of some benzo[b][1,8]naphthyridiens with HSA and BSA

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