A new and simple procedure for the synthesis of heptamethyl cyclohepta-1,3,5-triene-1,2,3,4,5,6,7-heptacarboxylate in a 51% yield is presented. An optimization of the reaction conditions was performed, and a convenient protocol for the isolation of the reaction product was developed. The structure of the key electrophilic intermediate was determined by means of NMR spectroscopy, and a plausible reaction mechanism is proposed.
The
novel class of gallium catalysts based on cationic gallium
phthalocyanines (RPcGa+) with SbF6
– and Sb2F11
– weakly coordinating
anions was developed in order to using in the catalytic version for
gallium-specific chemistry. Two cycloaddition/annulation processes
of styrylmalonates with aromatic aldehydes and styrene were implemented
in the catalytic version using this approach. The synthetic strategy
to gallium phthalocyanines and their structural features were studied
in details, including the use of specially adapted 71Ga
NMR spectroscopy in combination with 19F and 121Sb ones, as well as the mechanistic aspects.
The rearrangement of cyclopropylketone arylhydrazones generated in situ from arylhydrazine hydrochlorides and ketones leads to formation of tryptamine derivatives. The use of (2-arylcyclopropyl)ethanones in the reactions with model 4-bromophenylhydrazine hydrochloride gives branched tryptamines with aryl groups in the α-position to the amino group, while (2-methylcyclopropyl)ethanone gives a mixture of α- and β-substituted products in a ratio of 1:3. The method was found effective in the synthesis of enantiomerically pure tryptamine. Thus, (R,R)-(2-phenylcyclopropyl)ethanone gives the (S)-α-phenyltryptamine derivative with an enantiomeric excess over 99%.
The reaction of di(methoxycarbonyl)tetrazine with substituted cycloprop‐2‐ene‐1‐carboxylates gives a series of 3,4‐diazanorcaradienes and 1,2‐diazepines. The influence of the nature of cyclopropenes and the reaction conditions on its selectivity was investigated. The addition of nucleophiles to norcaradienes was studied and a rare example of the “walk” rearrangement in this class of compounds was revealed.
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