A method of improving the stability of a quaternary ammonium salt and a method of efficiently preparing the quaternary ammonium salt having improved stability.
7.beta.-Substituted mercaptoacetamido-7.alpha.-methoxycephalosporanic acid and derivatives thereof are prepared. These compounds are antibacterial agents with improved properties.
A method of improving the stability of a quaternary ammonium salt and a method of efficiently preparing the quaternary ammonium salt having improved stability.