Egon Spengler Egon Spengler Egon Spengler, PhD is a fictional character from the "Ghostbusters" franchise. He appears in the films "Ghostbusters" and "Ghostbusters II", in the animated television series "The Real Ghostbusters" and "Extreme Ghostbusters", in the video games "" and Beeline's "Ghostbusters". Spengler was portrayed by Harold Ramis in the films and voiced by him in "" and "Lego Dimensions", and voiced by Maurice LaMarche in the cartoon series. He is a member of the Ghostbusters and one of the three doctors of parapsychology, along with Dr. Peter Venkman and Dr. Ray Stantz. The character of Egon Spengler was named after
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