ChemInform Abstract: UNSATURATED ORGANOPHOSPHORUS COMPOUNDS FROM 1‐VINYLBENZOTRIAZOLE

NMR investigation of chlorophosphorylation products of N‐vinylazoles

“…However, contrary to pyrroles, the increase of nitrogen atoms in the azole cycle leads to the growth of acceptor role of the ring with respect to N-vinyl group. This fact is supported by noticeable low-field shift of the C β signal of the double bond observed in the 13 C NMR spectra. [5] The decrease of nucleophilicity of N-vinyl moiety of 1-vinylazoles compared to N-vinylpyrroles has to reduce the probability of side chlorination and resinification reactions during the phosphorylation with phosphorus pentachloride.…”

“…We have elucidated that 1-vinylbenzotriazole is phosphorylated with phosphorus pentachloride to furnish 2-(N-benzotriazole)ethenyltrichlorophosphonium hexachlorophosphorate (18), which can be readily converted to enaminophosphonic (19) and enaminophosphinic (20) acid dichloroanhydrides [13] (Scheme 6).…”

“…Since the electron-acceptor effect of the nitro group decreases the heteroring basicity, the phosphorylation of 1-vinyl-3,5-dimethyl-4-nitropyrazole (13,14) affords E-isomers [10] (Scheme 4).…”

“…The present work is dedicated to investigation of the phosphorylation process of N-vinylazoles by using 1 H, 13 C, 31 P and 15 N NMR technique. It has been found that 1-vinylpyrazoles, 1-and 2-vinylindazoles and 1-vinylbenzotriazole, characterized by lowered basicity of the azole ring, are phosphorylated with phosphorus pentachloride strictly through the N-vinyl group to afford β-phosphorylated N-vinylazoles in high yields.…”

“…The substitution of vinyl proton by chlorine atom in the α-position of enamine does not allow to use the 3 J(HH) and 3 J(PH) values for the assignment of E-and Z-isomers of phosphoruscontaining α-chloroenamines. Therefore, we have employed the 13 C NMR data to determine the geometry of these compounds.…”