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In the Staedel–Rugheimer pyrazine synthesis (1876), 2-chloroacetophenone is reacted with ammonia to the amino ketone, then condensed and then oxidized to a pyrazine. [5] A variation is the Gutknecht pyrazine synthesis (1879) also based on this selfcondensation , but differing in the way the alpha-ketoamine is synthesised.
Pyridine N-oxide is five orders of magnitude less basic than pyridine: the pK a of protonated pyridine-N-oxide is 0.8. [7] Protonated derivatives are isolable, e.g., [C 5 H 5 NOH]Cl. [3]
Chemically, acetylpyrazine is a pyrazine and a ketone. [2] Natural occurrence ... Note that modern synthesis is for 2-cyanopyrazine from 2-methylpyrazine ...
Leopold Rügheimer (May 5, 1850 – May 24, 1917) was a notable German chemist whose name is connected to the Staedel-Rugheimer pyrazine synthesis, a reaction that was discovered by himself and Wilhelm Staedel. Rügheimer was born in Walldorf (near Meiningen) in 1850 as the son of a merchant.
Dihydropyrazine and pyrazine synthesis [ edit ] Reaction of the lactam-derived enol phosphates 4 of 2,5-diketopiperazines with palladium catalyzed reactions (reduction, Suzuki and Stille cross-coupling reactions) enables the synthesis of a range of functionalised 1,4-dihydropyrazines 5 which can be aromatized to 1,4- pyrazines 6 in the presence ...
This was the first synthesis of a heteroaromatic compound. [24] [40] The first major synthesis of pyridine derivatives was described in 1881 by Arthur Rudolf Hantzsch. [41] The Hantzsch pyridine synthesis typically uses a 2:1:1 mixture of a β-keto acid (often acetoacetate), an aldehyde (often formaldehyde), and ammonia or
The Chichibabin pyridine synthesis (/ ˈ tʃ iː tʃ iː ˌ b eɪ b iː n /) is a method for synthesizing pyridine rings. The reaction involves the condensation reaction of aldehydes, ketones, α,β-Unsaturated carbonyl compounds, or any combination of the above, with ammonia. [1] It was reported by Aleksei Chichibabin in 1924.
Blaise ketone synthesis; Blaise reaction; Blanc reaction; Blanc chloromethylation; Blum–Ittah aziridine synthesis; Bodroux reaction; Bodroux–Chichibabin aldehyde synthesis; Bogert–Cook synthesis; Bohlmann-Rahtz pyridine synthesis; Bohn–Schmidt reaction; Boord olefin synthesis; Borodin reaction; Borsche–Drechsel cyclization; Bosch ...