Egon Spengler Venkman hadn't stopped him. Due to the large amount of collateral damage the city of New York suffered from the battle with Gozer, the Ghostbusters were sued by nearly every county and city agency in New York. Additionally a judicial restraining order was enacted which barred the Ghostbusters from performing services as paranormal investigators and eliminators, effectively putting them out of business. Five years after the events of the first film Egon was working at the Institute for Advanced Theoretical Research and was conducting experiments on human emotions. A negative test involved keeping a couple with marriage problems locked in
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