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Oxidative reactions of azines. 12. Dehydrogenation and oxidation of 2-methyl-9-phenyl-2,3-dihydro-1H-2-azafluorene

“…In this case the reaction mixture yielded the imide 8 (8.5% yield) and also the product of a more fundamental oxidation which was the substituted indanone 9 (yield 6%). The latter can be formed as the result of a cascade oxidation of the piperidine fragment initially to the 3-oxo derivative and then with cisdihydroxylation of the olefine bond to give a lactamdiol which then underwent oxidation fission of the C β -C γ bond and loss of one carbon atom [9]. In the 1 H NMR spectrum of the indanone 9 the protons of the methyl, methylene, and formyl groups give double singlet signals with the same 2:1 ratio of integrated intensities in each pair.…”

Rearrangements of N-Ylide Generated from 1-Ethoxycarbonylmethyl-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridinium Chloride

“…While continuing our systematic investigations of the chemistry of tetrahydropyridines [7][8][9], we studied the question of how the ratio of the expected products is affected by the presence of an aryl substituent at C(4) in the anhydro base (the N-ylide A) generated from 1-ethoxycarbonylmethyl-1-methyl-4-phenyl-1,2,3,6-tetrahydropyridinium chloride (1) when it is heated in the presence of sodium hydride. We found that the presence of a phenyl substituent has a substantial effect on the direction of the reaction: we isolated two compounds from the reaction mixture in 1.5:1 ratio with overall yield 64%, where the first compound had the structure of the expected 4-phenylpyrrolidine 2 while the other compound, to our surprise, proved to be the tetrahydroazepine 3.…”

An Oxidative Approach to a Hydroxypiperidinone Utilizing a Rh-Catalyzed C-H Activation Process

“…However, oxidative cleavage to produce aldehyde formamide 19 was the major pathway with a small amount (<10%) of the desired hydroxyl imide 18 being formed (Scheme ) . Quite nicely, simple oxidation with KMnO 4 in aqueous acetonitrile or aqueous acetone as the solvent provided the desired hydroxyl imide 18 as a single isomer with the acetamide and hydroxyl group in a cis ‐relationship. Overoxidation was also observed with cleavage to phenyl ketones 20 being significant side products.…”