We discovered that anilines were suitable for the direct C–H arylation of benzoquinone in the presence of tert-butyl nitrite. This new reaction proceeds through the in situ formation of a diazonium hydroxide species. The coupling can be carried out at room temperature under neutral, additive-free, metal-free, and aqueous conditions, allowing an environmentally friendly procedure.
A therapeutic agent for erection dysfunction and gynecoid incompetence, which is free from the problems involved in oral administration and direct injection, is safe, and exhibits excellent effect. A therapeutic agent for erection dysfunction and gynecoid incompetence for intranasal administration, percutaneous administration, or mucosal administration, such as oral mucosal administration or penis mucosal administration, characterized by containing as the active ingredient at least one compound having cyclic GMP phosphodiesterase inhibitory activity or salt thereof.