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Clar's rule has also been supported by experimental results about the distribution of π-electrons in polycyclic aromatic hydrocarbons, [7] valence bond calculations, [8] and nucleus-independent chemical shift studies. [9] Clar's rule is widely applied in the fields of chemistry and materials science.
Erich Clar (23 August 1902 – 27 March 1987) was an Austrian organic chemist, born in Hřensko, who studied polycyclic aromatic hydrocarbon chemistry. He is considered as the father of that field. [ 1 ]
Also, there are no carbocation rearrangements, as the acylium ion is stabilized by a resonance structure in which the positive charge is on the oxygen. The viability of the Friedel–Crafts acylation depends on the stability of the acyl chloride reagent. Formyl chloride, for example, is too unstable to be isolated.
A Polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings.Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, [1] or when biomass burns at lower temperatures as in forest fires.
The o-hydroxyaryl ketone first undergoes tautomerization to form the respective enol.The pi electrons of the double bond then attack the electrophilic carbon of the anhydride; a carboxylate anion is subsequently lost as a leaving group.
Scheme 1: Danheiser Benzannulation Reaction of an Alkyne and a Cyclobutenone(X= OR, SR, NR2) The Danheiser benzannulation is a regiocontrolled phenol annulation. This annulation provides an efficient route to form an aromatic ring in one step. [5]
Arnie Katz in Ahoy! stated that with GameMaker "a professional designer could use Gamemaker to produce a commercial-quality game, and even amateurs will be surprised and gratified". [1] Computer Gaming World called GameMaker "excellent". [2] Compute's!
Clemmensen reduction is a chemical reaction described as a reduction of ketones or aldehydes to alkanes using zinc amalgam and concentrated hydrochloric acid (HCl). [1] [2] This reaction is named after Erik Christian Clemmensen, a Danish-American chemist.