9. The synthesis of trypanocides. Part II. 4-Amino-6-(2-amino-1 : 6-dimethylpyrimidinium-4-amino)-1 : 2-dimethylquinolinium (“Antrycide”) salts and related compounds

Ainley, A. D.; Curd, F. H. S.; Hepworth, W.; Murray, Arthur George; Vasey, C. H.

doi:10.1039/jr9530000059

Cited by 8 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CHCl 3 layers were combined, dried over MgSO 4 , and filtered, and the the solvent was removed by rotary evaporation. The solid was recrystallized twice from C 2 H 5 OH (5.6 g, 92%): mp 111−112 °C (lit . mp 113 °C); 1 H NMR (CDCl 3 ): δ 5.57 (s, 1H), 3.35 (s, 3H), 3.28 (s, 3H), 2.19 (s, 3H).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Photoinduced Electron Transfer to Pyrimidines and 5,6-Dihydropyrimidine Derivatives: Reduction Potentials Determined by Fluorescence Quenching Kinetics

1997

View full text Add to dashboard Cite

The dynamics of flourescence quenching of excited state electron donor sensitizers by various pyrimidine and 5,6-dihydropyrimidine substrates was examined. For all of the substrates studied the rate constant of fluorescence quenching (k q) increases as the excited state oxidation potential (E ox * ) becomes more negative. The dependence of k q on E ox * in each case is well described by the Rehm−Weller relationship. Fits of the data to this relationship allow for the estimation of the reduction potentials of the substrates (E red). The pyrimidines 1,3-dimethylthymine, 1,3-dimethyluracil, and 1,3,6-trimethyluracil give E red values (in CH3CN) ranging from −2.06 (vs SCE) to −2.14 V. Their dihydro derivatives, 1,3-dimethyl-5,6-dihydrothymine, 1,3-dimethyl-5,6-dihydrouracil, and 1,3,6-trimethyl-5,6-dihydrouracil gave E red values ranging from −1.90 to −2.07 V. The higher E red values for the dihydropyrimidines compared with their unsaturated derivatives is attributed to aromatic stabilization in the pyrimidines, which is not present in the dihydro derivatives. In addition, the E red for both the trans- syn and cis-syn diastereomers of the dimethylthymine cyclobutane dimer was examined using the same method. The trans-syn dimer gives an E red of −1.73 V and the cis-syn dimer gives an E red of −2.20 V. This remarkable difference is attributed to a stereoelectronic effect. The cis-syn dimer anion radical suffers from an unfavorable charge−dipole interaction between the added electron and the O4 carbonyl group in the remaining pyrimidine ring. In contrast, the trans- syn dimer anion radical shows mainly a stabilizing inductive electron-withdrawing effect of the remaining O4 carbonyl group. Solvent effects on E red were also examined. It is shown that the protic solvent, CH3OH, significantly stabilizes the anion radicals, raising E red by ca. 400 mV over the value in CH3CN.

show abstract

Section: Methodsmentioning

confidence: 99%

“…1 H NMR (CDCl 3 ): δ 3.28 (dd, J ) 6.2, 6.1 Hz, 1H), 3.13 (s, 3H), 3.09 (m, 1H), 3.03 (s, 3H), 2.71 (m, 1H), 1.21 (d, J ) 6.9 Hz, 3H). 13 (35), 72 (27), 58 (35), 55 (46).…”

Section: Methodsmentioning

confidence: 99%

Photoinduced Electron Transfer to Pyrimidines and 5,6-Dihydropyrimidine Derivatives: Reduction Potentials Determined by Fluorescence Quenching Kinetics

1997

View full text Add to dashboard Cite

show abstract

“…Antrycide dimethyl sulphate (Curd & Davey, 1949;Ainley, Curd, Hepworth, Murray & Vasey, 1953), Paludrine hydro-33 Bioch. 1962, 84 chloride (Curd & Rose, 1946a, b), 4-methylPaludrine (Curd, Hendry, Kenny, Murray & Rose, 1948) and Paludrine metabolite (Carrington, Crowther & Stacey, 1954) were obtained from the Pharmaceuticals Division, Imperial Chemical Industries Ltd., as were the Antrycide analogues, referred to in this paper as (A) and (B) respectively, i.e.…”

Section: Methodsmentioning

confidence: 99%