1,5-Naphthyridines and their n-oxides III. Synthesis and biological activity of some mono- and disubstituted 1,5-naphthyridines and their n-oxides
In order to search for biologically active compounds in the 1,5-naphthyridine series, we synthesized 2-mercaptoand 2-(4'-aminobenzenesulfonamido)-l,5naphthyridines and some of their 6-substituted derivatives. 2-(4'-Aminobenzenesulfonamido)-l,5-naphthyridine (I) was obtained by reaction of 2-amino-l,5naphthyridine with 4-carbomethoxyaminobenzenesulfonyl chloride in pyridine with subsequent saponification of the carbomethoxy group in the resulting 2-(4'carbomethoxyaminobenzenesulfonamido)-l,5-naphthyridine (II).
Tautomerism in side-chain derivatives of n-heterocycles
Abstract NMR and UV spectra of some α (ψ)cyano-, carbethoxy-, and acylmethyl derivatives of 2-oxo-1,2-dihydroquinoxaline, 2-oxo-1,2-dihydro-6,7-benzoquinoxaline, 3,4-dihydro-1,4,2H-benzoxazone, quinaxoline, and quinoline, were recorded in chloroform, dimethyl sulfoxide, and trifluoro- acetic acid. The results indicate the existence of tautomeric equilibria, with noticeable contribution of the enaminic structures B or D, depending on the solvent and the nature of the heterocycle. Relationhips between some NMR parameters and tautomeric structures were observed.
Cholesterol synthesis from acetate in the diabetic liver.
Brady and Gurin (1) recently compared the ability of liver slices prepaped from both normal and diabetic rats to incorporate added acetate into cholesterol. They drew the conclusion that the conversion of acetate to cholesterol in the diabetic liver is “apparently unimpaired, although this process may be inhibited when diabetes is sufficiently prolonged and severe.” In view of our interest in the relation of cholesterol synthesis to arteriosclerosis, the development of which is generally regarded as being accelerated in diabetes (2), we have reinvestigated cholesterol synthesis from acetate in diabetes. A definite increase in cholesterol formation in the diabetic liver is demonstrated here. It is further shown that, as a result of insulin injections in a diabetic rat, slices subsequently prepared from its liver have a reduced capacity to synthesize cholesterol.