Microwave spectra of isotopic thiazoles. Molecular structure and 14N quadrupole coupling constants of thiazole

The Microwave Spectrum of Oxazole

“…In analogy with the view taken by previous workers [10], the dipole moment of oxazole may be interpreted as the vector sum of a moment , associated with the pyridine-like nitrogen atom, and a contribution [Aresid. describing the polarity of the residual ring structure.…”

The Microwave Spectrum of Oxazole I. The Complete Structure by DRM Microwave Spectroscopy

“…According to an idea first formulated by Nygaard et al [17] the structure parameters of oxazole would be expected to resemble closely those of furan in the molecular fragment 0(1)C(5)C(4) and those of 1,3,4-oxadiazole in the section 0(1)C(2)N(3), with the length N(3)-C(4) about equal to the average between the C-C bond of furan (1.431 Ä) and the N-N bond of 1.3.4-oxadiazole (1.395 Ä), and with the angle C(5)0(1)C(2) half-way between its values in these two molecules. From Figure 2 it is readily seen however that, although a qualitative correlation between the oxazole parameters and corresponding quantities in furan or 1,3,4-oxadiazole is fairly obvious, there is no ring bond in oxazole whose length would support the outlined hypothesis in a quantitative way.…”

“…The rotational parameters of oxazole and its isotopic species are listed in the lower half of Table 1 (rows [8][9][10][11][12][13][14][15][16][17]. The upper half of this table summarises relevant information concerning the rotation of the inertial axes with respect to the parent form under isotopic substitution (row 3), the squared dipole moment components (row r 4) and the quadrupole coupling constants (row 5), as well as the number of transitions (N) contained in the final LSQ fit for every isotopic form (row 6).…”

Structure de l'amino-2 thiazole-1,3

“…La structure du thiazole (Nygaard et al, 1971) +tablie par spectroscopic de microondes fournit un +l+ment de comparaison en donnant la g+om+trie de la base libre non substitute. Plusieurs m~moires ont paru depuis sur la structure de d+riv+s substitu~s en diff6rents sites.…”