1,2-Dicyanocyclobutene

Abstract

[3716-97-0] C6H4N2 (MW 104.11) InChI = 1S/C6H4N2/c7-3-5-1-2-6(5)4-8/h1-2H2 InChIKey = VMFXYPBFHHRGKQ-UHFFFAOYSA-N (reactive dienophile in [4 + 2],1 [3 + 2],2 and [2 + 2]3 Diels–Alder additions; reactive diene in [4 + 2] inverse electron demand Diels–Alder additions upon in situ thermolytic cleavage to 2,3-dicyanobutadiene) Alternate Name: cyclobutene-1,2-dicarbonitrile. Physical Data: bp 58–60 °C/0.06 mmHg; nD20 1.4926; d204 1.033 g cm−3; IR (neat) cm−1: 3002, 2957, 2230, 1612, 1422, 1251, 1169, 1003, 623; 1H NMR δ 2.91 (s, 2H). Solubility: insol H2O; sol most organic solvents. Form Supplied in: colorless liquid; not commercially available. Preparative Methods: may be prepared by several methods.4 The most convenient involves the chlorination of 1,2-dicyanocyclobutane with Phosphorus(V) Chloride followed by dechlorination with Triethylamine in refluxing benzene to give the reagent in good yield1, 5 (eq 1). (1) Purification: prepared by the method described, the reagent may be used directly for most cycloadditions. To remove trace impurities (1–4%) and obtain the pure compound, stir for 4 h over Raney cobalt under N2 at 70 °C, then distill directly under vacuum; purity may be assessed by gas chromatography.5