Proton spin-spin coupling constants in isothiazole, isoxazole, and some of their alkyl derivatives was written by Wasylishen, Roderick E.;Rowbotham, J. Brian;Schaefer, Ted. And the article was included in Canadian Journal of Chemistry in 1974.Computed Properties of C4H5NO This article mentions the following:
The signs and magnitudes of the spin-spin coupling constants over three to six bonds between protons in isothiazole, isoxazole, and in 10 of their alkyl derivatives are discussed in terms of the coupling mechanisms. The chem. shifts of ring protons and Me protons arise from a common mechanism originating in the ring but are not simply related to electron ds. calculated by MO theory at the CNDO/2 level of approximation In the experiment, the researchers used many compounds, for example, 5-Methylisoxazole (cas: 5765-44-6Computed Properties of C4H5NO).
5-Methylisoxazole (cas: 5765-44-6) belongs to isoxazole derivatives. Isoxazoles are aromatic heterocycles containing an N–O bond. The weakness of this bond allows the ring opening of these heterocycles under reductive conditions. Isoxazole can be synthesised via a variety of methods. Examples include via a 1,3-dipolar cycloaddition of nitrile oxides with alkynes.Computed Properties of C4H5NO
Referemce:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem