Egon Spengler a P.K.E. surge of dangerous proportions. Egon was particularly critical of Walter Peck's actions, and his attitude that the Ghostbusters were responsible for the explosion of the containment unit that occurred when Peck ordered a municipal worker to shut the unit down. After their encounter with Stay Puft, Egon suggested an atypical solution when he recommended blasting Gozer's dimensional portal while crossing the proton streams to reverse the particle flow and send Gozer back to his/its dimension. Egon once tried to drill a hole in his own head (a process known as trepanning), which he says "would have worked" if
Pictet–Spengler reaction tetrahydroisoquinoline synthesis. Reaction conditions are generally harsher than the indole variant, and require refluxing conditions with strong acids like hydrochloric acid, trifluoroacetic acid or superacids. Instead of catalyzing the Pictet-Spengler cyclization with strong acid, one can acylate the iminium ion forming the intermediate "N"-acyliminium ion. The "N"-acyliminium ion is a very powerful electrophile and most aromatic ring systems will cyclize under mild conditions with good yields. Tadalafil is synthesized via the "N"-acyliminium Pictet–Spengler reaction. This reaction can also be catalyzed by AuCl and AgOTf. When the Pictet–Spengler reaction is performed with an aldehyde other than formaldehyde, a new chiral center