Quinolyl radicals

On the other hand, the 3-quinolyl radical (from diazotized 3-amino-... 

The coupling rate of PhS" ions with aryl radicals has been determined in different solvents. Thus 9-anthryl radical has a rate constant of 4.5 x 108 M"1 s"1 in DMSO, 2-quinolyl radical a rate constant of 1.4 x 107 M 1 s 1 in liquid ammonia and p-cyanophenyl radical a rate constant of 2 x 1010 M"1 s"1 in MeCN273. 

Similar rate constants (1.2-3.2 x 109) for the reactions of 2-quinolyl radical with sulphanions 221-225 have been determined in liquid ammonia. The partition between the monosubstitution 227 and the disubstitution products 228 depends not only on the stability of the... 

The selectivity of the 2-quinolyl radical is greater than that of the phenyl radical. Consider the results in the case of 3-methyl-2-butanone which gives two enolate ions when deprotonated by amide ion. The less substituted enolate ion is believed to be the major component. When this mixture is allowed to react with the 2-quinolyl... 

Bennasar (00CC2459, 02JOC7465) reported a 5-exo-trig cyclisation of a 2-quinolyl radical onto a 2-pyridone with contemporaneous desul-phurisation of substrate 209a-c, to synthesise the camptothecin precursor 210a-c, further manipulated to afford (+ )-20-deoxycamptothecin (Scheme 56). 

While the above examples highlight the synthetic utility of pyridyl, indolyl, thienyl and quinolyl radicals, there are few reports on other... 

The enolate ions of acyclic and cyclic aliphatic ketones are among the most studied carbanions in photostimulated Sr I reactions. Absolute values of rate constants for the reactions of aryl radicals with nucleophiles have been determined electrochemicaUy for a large number of cases. Most of the values are close to the diffusion limit. For instance, the range of rate constants for the coupling of 2-, 3-, and 4-cyanophenyl 1-naphthyl 3-pyridyl and 3- and 4-quinolyl radicals with CHjCOMe ions is on the order of 10 to 10 M s in liquid ammonia.- > ... 

It is important to note that sodium methylate initiates only the formation of 4-phenylthio-iso-quinoline the product of the competing substitution, 4-methoxy-iso-quinoline, is produced only in traces. The methylate ion, however, converts a part of the iso-quinolyl a-radicals into the unsubstituted iso-quinoline and produces formaldehyde. 

Similar A-fluoro perfluoroheterocyclic sulfonamides of the type HetF(NF-S02R) have been synthesized, where HetF represents an aromatic perfluoroheterocyclic radical of valency n from naphthyridinyl, quinolyl and isoquinolyl.127... 

A number of contracted radical names derived from trivial parent names are in common use, e.g., 2-furyl, 8-quinolyl, 2-benzo[6]thienyl (see IUPAC Rule B-2, tables). 

The reaction of aryl and hetaryl halides with the nitrile-stabilized carbanions (RC -CN) leads to derivatives of the type ArCH(R)CN. Sometimes, however, dimeric products of the type ArCH(R)CH(R)Ar are formed (Moon et al. 1983). As observed, 1-naphthyl, 2-pyridyl, and 2-quinolyl halides give the nitrile-substituted products, while phenyl halides, as a rule, form dimers. The reason consists of the manner of a surplus electron localization in the anion radical that arises upon replacing halogen with the nitrile-containing carban-ion. If the resultant anion radical contains an unpaired electron within LUMO covering mainly the aromatic ring, such an anion radical is stable, with no inclination to split up. It is oxidized by the initial substrate and gives the final product in the neutral form, Scheme 1-7 ... 

Initial reports on quinolyl and isoquinolyl radicals were first published in the 1970s (75JA1548, 73JA6863, 72JOC3199), but their use in the synthesis of heterocycles was first reported by Comins (94TL5331), where the synthesis of (S)-camptothecin 206 is described. The radical step takes place in the construction of the C ring (Scheme 54). 

Boger (98TL2227) used a 5-quinolyl and a 4-indolyl (Scheme 39) radical in a 5-exo-trig cyclisation to obtain 208, the tricycle moiety that is part of the more complex structure of CC-1065 and duocarmycin analogous, which are potent antitumour antibiotics (Scheme 55). 

C,H,N,0]- Anion radical from di-p-quinolyl ketone 69Morl 246 ... 

A soln. of startg. oxime ester (prepared from biphenyl-4-carboxylic acid and benzophenone oxime) in carbon tetrachloride irradiated with a 400 W high-pressure Hg-lamp through a Pyrex filter under N2 at room temp, until reaction complete 4-chlorobiphenyl. Y 88%. This radical method is generally applicable to ar., hetar. (e.g. pyridyl, quinolyl, quinoxalyl), and aliphatic acids (prim., sec. and tert.). Ketone, amide, and hydroxyl groups remained unaffected. F.e.s. M. Hasebe, T. Tsuchiya, Tetrahedron Letters 29, 6287-90 (1988). 

Resonance Raman spectroelectrochemistry was used to follow radical anion formation and dechelation in electrochemically-reduced binuclear copper(I) complexes based on 2,3-di(2-quinolyl)quinoxaline. Resonance Raman results for radical cations derived from P-substituted Cu(TPP) systems gave information on orbital ordering. ... 

---