Klaus Neisser
1911 - 2003

Klaus Neisser was born in Frankfurt on the Main in 1911 as the youngest child of Prof. Dr. med. Max Neisser and Emma Eleonore Neisser, née Hallgarten. He had two older siblings: Elise Charlotte, called Liselotte (1902-1994) and Gerhard Ernst (1905-1984). At the time, the Neisser family lived at Miquel street 21. Klaus Neisser's mother Emma Eleonore was the daughter of the Jewish patron Charles L. Hallgarten (1838-1908) and Elise Mainzer (1840-1895), who also came from a Jewish family.

His father, Dr. Max Neisser, was a member of the Municipal Health Commission of Frankfurt on the Main in 1911 and Director of the Municipal Institute of Hygiene. Like his father, Klaus Neisser was also a Protestant. Accordingly, he noted on his registration card for the University of Frankfurt in April 1931 under religion: "ev." (evangelisch, i.e. Protestant). Klaus Neisser graduated from the Wöhler Realgymnasium at Easter 1930.

Klaus Neisser married but so far we dont know his wife's name. They had two children in Brazil: his son Maximiliano Piero, born in Sao Paulo in November 1941, and his daughter Adriana, also born in Sao Paulo in August 1948. His son, Prof. Dr. Maximiliano Piero Neisser, graduated in dentistry from the University of Sao Paulo in 1972 and obtained a master's degree in dentistry from the Estadual Paulista Júlio de Mesquita Filho University in 1992. He also received a doctorate from the Estadual de Campinas University in 1997.

Klaus Neisser studied chemistry at the University of Frankfurt from April 1931 to November 1932 and then at the University of Göttingen. He finally completed his doctorate in organic chemistry at the University of Göttingen under Prof. Dr. Adolf Windaus (1876-1959). In the fall of 1935, Nazi students at his institute wanted to expel Klaus Neisser because of his Jewish parents. However, Adolf Windaus turned to the Reich Minister for Science, Education and National Education to take action against these students. However, as Windaus did not expect to receive permission, he offered his own resignation on April 1, 1936. Surprisingly, the main student activists had to leave the University of Göttingen, while Klaus Neisser was able to complete his doctorate. He was awarded his doctorate in January 1936 with a thesis on "Synthetic experiments on degradation products of the antineuritic vitamin".

Klaus Neisser emigrated to Brazil after completing his doctorate. He worked there from 1937 to 1938 at the Instituto Butantan, the coffee institute in Sao Paulo, as an assistant to Karl Heinrich Slotta (1895-1987). For example, Neisser published an article on the chemistry of coffee together with Slotta in the journal "Berichte der deutschen chemischen Gesellschaft", in which both described a new method for determining chlorogenic acid. Slotta had emigrated to Brazil in 1935 because his wife was Jewish. Klaus Neisser and Karl Heinrich Slotta discovered the Serini reaction, which can be used for the synthesis of steroids. Together with Gherard Szyszka and Karl Heinrich Slotta, Klaus Neisser also succeeded in isolating crotoxin, a toxic protein from rattlesnake venom.

Klaus Neisser was recommended for membership of the Frankfurt on the Main section of the German and Austrian Alpine Club in March 1933 by his father Prof. Dr. med. Max Neisser and the Jewish lawyer Dr. Adolf Fuld. He was a student at that time, so he joined the student section.

As his parents came from Jewish families, he was probably expelled from the Frankfurt section after the introduction of the so-called "Aryan paragraph". He may also have left again in 1933. Due to a lack of sources, we cannot say whether he took part in events organized by the student section or the Frankfurt section at all.

After Klaus Neisser received his doctorate from the University of Göttingen in January 1936, he emigrated to Brazil and lived in Sao Paulo. There he married and had two children, his son Maximiliano Piero (born in November 1941) and his daughter Adriana (born in August 1948). His father Max Neisser died in February 1938, while his mother Emma Eleonore Neisser was able to emigrate to Gerhard Ernst Neisser, Klaus' brother, in the USA in October 1938. However, she died in New York City in November 1939.

The brother Gerhard Ernst Neisser lived in New York City after his emigration to the USA and changed his name there to Gerard Ernest Neisser. He died in June 1984 in Larchmont (New York). His sister Liselotte Dieckmann emigrated with her family via Italy (1933) and Turkey (1934) to the USA in 1938. She went to St. Louis (Missouri), where she died in 1994, just three days before her 92nd birthday.