Neubauer was born in Karlsbad (then in Bohemia) to physician Wolfgang and Hedwig Arnstein née Sadler.
He then went to the German University in Prague he received a medical degree in 1898 and became interested in physiological chemistry through the influence of Karl H. Huppert.
Gastric juice incubated with glycyl-tryptophan for twenty four hours tested with bromine to see if free tryptophan causes a rose-violet colour was used as an indication of stomach carcinoma.
In 1918 he became head physician at Schwabinger Hospital, working there until his dismissal by the Nazi government in June 1933 as a person of Jewish ancestry.
With assistance and support from The Society for the Protection of Science and Learning, he emigrated to England in 1939 along with his wife Lilly Caroline (1876-1962, who was married to composer Fritz Cassirer until his death) and worked in Oxford for the remainder of his life.