Search results
Results from the WOW.Com Content Network
Hans Freiherr [a] von Pechmann (1 April 1850 – 19 April 1902) was a German chemist, renowned for his discovery of diazomethane in 1894. [ 1 ] [ 2 ] Pechmann condensation [ 3 ] [ 4 ] and Pechmann pyrazole synthesis . [ 5 ]
The Pechmann condensation as applied to 7-hydroxy-4-methylcoumarin For coumarins unsubstituted at the 4-position, the method requires the use of formylacetic acid or ester. These are unstable and not commercially available, but the acid may be produced in situ from malic acid and sulfuric acid above 100 °C.
Diazomethane is an organic chemical compound with the formula CH 2 N 2, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound.In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost universally used as a solution in diethyl ether.
Hans von Pechmann: Chemist, renowned for his discovery of diazomethane in 1894. Pechmann condensation and Pechmann pyrazole synthesis. Julius Richard Petri: Bacteriologist who is generally credited with inventing the Petri dish while working as assistant to Robert Koch. Emil Pfeiffer: Discovery of Infectious mononucleosis
1898: Synthesis of polyethylene, the most common plastic, by Hans von Pechmann [160] 1898: First synthesis of purine by Emil Fischer. He had also coined the word in 1884. [161] Early 20th century: Schlenk flask by Wilhelm Schlenk [162] 1900s: Haber process by Carl Bosch and Fritz Haber [134] 1902: Ostwald process by Wilhelm Ostwald [163]
Adolf von Baeyer Otto Bayer demonstrated in 1952 his invention Polyurethan Friedrich Bergius Carl Bosch Eduard Buchner Robert Wilhelm Bunsen. Lambert Heinrich von Babo; Manfred Baerns
Pechman or Pechmann is a surname of German origin. Notable people with that name include: Joseph A. Pechman (1918–1989), American economist; Hans von Pechmann (1850–1902), German chemist; Marsha J. Pechman (born 1951), American judge; Matthias Pechmann, East German swimmer
Two German chemists also preceded Schlotterbeck in discovery of the reaction, Hans von Pechmann in 1895 and Viktor Meyer in 1905. [4] [5] The reaction has since been extended to the synthesis of β-keto esters from the condensation between aldehydes and diazo esters. [6] The general reaction scheme is as follows: General Scheme for Buchner Reaction