Recherches dans la série des azoles

The synthesis and unimolecular decomposition of four novel Δ1-1,2,4-triazolines

“…Unfortunately those were also the products when the thermolyses were done in methyl acrylate or in dimethyl acetylenedicarboxylate (DMAD), two efficient dipolarophiles (8). Heterocycles 13 and 16 were identified on the basis of the spectroscopic data, which correspond well with those oi similar known aromatic heterocycles (Table 1) (12)(13)(14)(15)(16)(17)(18)(19)(20). A significant feature of the nrnr data is that the two methyl groups that are not part of the t-Bu substituent are magnetically equivalent, providing strong evidence that the 1,2,4-triazoline ring of 12 and 15 is not present in 13 and 16.…”

A theoretical study of the mechanism of oxidation of 1H-pyrazolines to 1H-pyrazoles by molecular bromine

“…8,9 We maintain this mechanism in subsequent papers of 1964 and 1965, 10,11 and corrected it in 1967. 5 In the meantime, in 1966 a paper by Closs and Heyn appeared in which they prove conclusively that the intermediate was a 3-bromo-1-pyrazoline 5 and not a 1-bromo-2-pyrazoline 2.…”

Synthesis and elucidation of structure of hydrazones derived from N-(2,4-dimethylphenyl)-3-oxobutanamide

“…The UV spectra of products 3 show three ranges of absorption maxima at 203-207, 235-271, and 376-393 nm, except compounds 3e and 3f which had four absorption maxima. Absorption bands attributed to an azo function between 332-360 nm [21][22] and above 400 nm 23 are missing.…”