The synthesis of macrocyclic polyether-diesters incorporating 1,10-phenanthrolino and 1,8-naphthyridino subunits

The preparation of a series of macrocycles, formed by reaction of HO-(-CH₂-CH₂-O-)_nH with 1,10-phenanthroline-2,9-dicarbonyl chloride (n = 2,3,4) and 1,8-naphthyridine-2,7-dicarbonyl chloride (n = 3,4), is described. An improved synthetic route to 2,7-dimethyl-1,8-naphthyridine 9 is also reported.     

Novel products from attempted michael addition to 1-methyl-1,2,5,6-tetrahydropyridine-4-carbonitrile

The reaction of some phenols with the title compound, in the presence of sodium, gives 2-(2-hydroxyaryl_piperidine derivatives. Geometrical isomers have been separated, which differ in having an equatorial (A) or axial (B) cyano group on the piperidine chair (the methyl and aryl groups are equatorial in both forms). The x-ray crystallographic structures of an example of each of A and B are reported and the proton NMR spectra are assigned.     

Far-Red Dibenzo[a,j]Perylene-8,16-Dione Dyes as Fluorescent Enzyme Substrates and Tags for Biomolecules

The synthesis of fluorescent 2,10-derivatives of the title chromophore are described. The substituents contain amino-reactive N-hydroxysuccinimde ester and thiol-reactive iodoacetamide groups for attachment to biomolecules. A phosphate derivative was also prepared as an enzyme substrate.     

1H NMR Studies on the Methylation,Protonation, and Hydration Sites in Some Benzo[b]Naphthyridines (Azaacridines)

Abstract

The 300.13 MHz ¹H NMR spectra of the methylated and protonated 6(9)-methylbenzo[b][1,x] naphthyridines (x=5, 6, 7, 8) (5-methylazaacridines) were collected at 298 K in deuterated dimethyl sulfoxide and chloroform, respectively. The methylation and protonation sites were assigned by comparisons of these data with those of the free bases. The results were compared with similar data for related heterocycles and showed that both methylation and protonation occur at the nitrogen in the outer pyrido ring in all four series.

The hydration site in some 2-and 3-azaacridines was determined by specific line broadening in their ¹H NMR spectra to be the same nitrogen as that involved in methylation and protonation. Variable temperature ¹H NMR demonstrated that the specific line broadening results from some changes of ¹⁴N quadrupolar relaxation produced by the slow chemical exchange between unhydrated and hydrated species. Deuterium exchange experiments indicated that the direct spin-spin interaction of a water proton and the protons alpha to the hydrated nitrogen may also have some contribution.     

N-Methyl chemical shifts in some 2-, 3- and 4-substituted N-methylpyridinium salts

The chemical shifts of the N-methyl group in a series of 2-, 3- and 4-substituted N-methylpyridinium salts have been measured in DMSO solution. The shift is primarily affected by resonance interaction between the substituent and aza group, and the results suggest that the resonance effect from a 2-substituent is at least as great as from the corresponding 4-substituent.     

A cheap alternative to valinomycin for certain analyses with the potassium ion-selective electrode

A pyridine-based macrocylic ionophore containing a 15-membered ring cavity and an octoxy side-chain to confer compatibility with poly(vinyl chloride) is described. This cheap reagent gives a potassium ion-selective PVC membrane electrode which, except for a higher sodium interference, compares well with valinomycin for analyses where the sodium/potassium ratio is ?1. Near-Nernstian response is obtained for 10^?1–10^?5 M potassium ion.     

Novel derivatives of the benzo[b][1,6]naphthyridine system

An efficient synthesis of 2‐hydroxy‐6‐methylbenzo[b][1,6]naphthyridin‐1(2H)‐one was devised. The hydroxy group was alkylated, acylated and replaced by hydrogen. Electrophilic nitration, bromination and chlorosulfonation occurred readily in the 4‐position. From the last, various sulfonamide derivatives were prepared. A selection of the products was screened by the National Cancer Institute. Cytotoxicities were generally low.