Naphthyridine Chemistry. XVII: Di-N-alkylated Naphthyridines

Abstract

It has been shown that the N,Nf-dimethylated naphthyridines form pseudo bases by hydroxide addition in the quinolinoid rather than the isoquinolinoid ring, where possible.The charge repulsion in the 1,8-dimethyl-1,8-naphthyridinium ion is reflected by its facile partial conversion to a mono-pseudo base at room temperature. A variable temperature study of this equilibrium reaction is described.On a demontre que les naphthyridines dimethylees en position N , N ' forment, si possible, des pseudobases par l'addition d'un groupement hydroxyle au cycle quinolinoide plutbt qu'au cycle isoquinolinoide.La repulsion des charges dans l'ion dimethyl-1,8 naphthyridinium-1,8 est mise en Cvidence par sa conversion facile et partielle en une mono pseudo-base a la temperature ambiante. Une etude a diverses temperatures de cette reaction d'equilibre est aussi decrite.

Quaternary Nitrogen Heterocycles. V. Substituent Effects on the Equilibrium Constants for Pseudobase Formation from Quinolinium and Isoquinolinium Cations

“…The data in Table 4 in 1 M NaOD-D,O agree well with the data for these two dications in 0.5 M NaOD-D20 as reported by Pokorny and Paudler (6). The ionization of each of the pseudobases in the present study with pKRo -< 12, suggests that all the data in Table 2 of reference (6) actually refer t o the pseudobase alkoxide ions (zwitterions) rather than to the pseudobases themselves.…”

“…The p.m.r. spectral data for these naphthyridinium dications in D,O were in if we assume that k,/k4 for this cation agreement with the data given by Pokorny and Paudler is similar to the value previously found for the (6). related 2-methyl-4-nitroisoquinolinium cation I~phenacylquinolinium Bromide (8.8 lo6 (211, then k1 = 6.4 x lo6 M -' s-'9…”