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).
On the reactivity of 4-cyano-1,3-dichloro-7-methyl-5,6,7,8-tetrahydro-2,7-naphthyridine with several amines in different experimental conditions: monosubstitution, disubstitution, and a new unexpected rearrangement
Abstract The reactivity of 4-cyano-1,3-dichloro-7-methyl-5,6,7,8-tetrahydro-2,7-naphthyridine 1 with nucleophiles has been investigated. The different reactivity of the two chlorine atoms in 1 enabled us to obtain, by using different experimental conditions, the mono- and the di-amino-substituted derivatives of 5,6,7,8-tetrahydro-2,7-naphthyridines 2 and 3, respectively. Thus, by carrying out the reaction in a low-boiling solvent and in the presence of a quasi-stoichiometric amount of amine, the mono-substituted derivatives 2 were obtained, which under harsher conditions was transformed into the diamino derivatives 3 when using an excess of amine. During the synthesis of some diamino derivatives 3 a new rearrangement was observed with formation of 1-oxo derivatives of 3,4-dihydro-2,7-naphthyridines 4. The structure of the unexpected compounds 4 was confirmed by X-ray crystallography. A mechanism for the rearrangement is tentatively suggested.
2‐Trifluormethyl‐pseudooxazolone‐(5)
Mit Hilfe von Protonenresonanz-Spektren wird gezeigt, das die aus N-TFA-Aminosauren hervorgehenden Azlactone 2-Trifluormethyl-pseudooxazolone-(5) sind. Diese Spektren werden mit denjenigen normaler Oxazolone-(5) verglichen. Die Bromierung der 2-Trifluormethyl-pseudooxazolone-(5) erfolgt am α-standigen C-Atom der 4-standigen Seitenkette.