Egon Spengler him, which leaves him a little flustered. He celebrates his 40th birthday during this series, which would put him in his late twenties when "The Real Ghostbusters" began. Age is the largest factor causing Spengler to having transition from active ghost hunting to a mentorship role; in one episode where the original Ghostbusters guest starred on an episode the audience clearly sees middle adulthood has affected the speed and weakened the stamina of the original Ghostbusters. Although Egon Spengler does not appear in the 1990 "The Earth Day Special", his character and status as a Ghostbuster is mentioned, and Harold
Pictet–Spengler reaction imine generated from the condensation of the aldehyde and amine. This helps to explain the need for an acidic medium in some substrates, as the imine may not be electrophilic enough for ring closure to occur but the Iminium ion is capable of undergoing the reaction. The Pictet-Spengler reaction is widespread in both human industry and biosynthesis. It has remained an important reaction in the fields of alkaloid and pharmaceutical synthesis since its inception, where it has been employed in the development of many beta-carbolines. The enzyme strictosidine synthase is an example of nature utilizing the Pictet-Spengler reaction, which generates