New amidines from intramolecular cyclization in triflic acid of nitroketene aminals with a tethered phenyl ring
نویسندگان
چکیده
منابع مشابه
Phosphazene-catalyzed intramolecular cyclization of nitrogen-tethered alkynyl esters.
Intramolecular cyclization of nitrogen-tethered alkynyl esters catalyzed by phosphazene organosuperbases P2-tBu and P4-tBu was investigated. Both acyclic and cyclic substrates underwent 5-exo-dig and 5-endo-dig cyclization. This reaction is a rare example of the intramolecular addition of enolates of simple esters to alkynes.
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The reaction of N-acylaminoalkyl diethylacetals with triflic acid in benzene gave N-acylamino-diphenylalkyls. The proposed intermediates are the N-acyl-2-phenyl cyclic amides, which themselves are similarly converted to N-acylamino-diphenylalkyls.
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Condensation of an aldehyde with an α-amino-ester, followed by a tandem process involving cyclization to a seven-membered ring, deprotonation to an intermediate azomethine ylide and intramolecular dipolar cycloaddition gave tricyclic products related to stenine and neostenine.
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The total synthesis and structure determination of cis- and trans-flocoumafen was described. The key synthetic steps involve Knoevenagel condensation with p-methoxybenzaldehyde, in situ decarboxylation and intramolecular ring cyclization to construct the tetralone skeleton. Stereospecific reduction of the O-alkylated ketone 13 afforded good yield of precusor alcohol 5. Final coupling of alcohol...
متن کاملEvidence for a Morin type intramolecular cyclization of an alkene with a phenylsulfenic acid group in neutral aqueous solution.
Sulfenic acids (RSOH) are among the most common sulfur-centered reactive intermediates generated in biological systems. Given the biological occurrence of sulfenic acids, it is important to explore the reactivity of these intermediates under physiological conditions. The Morin rearrangement is a synthetic process developed for the conversion of penicillin derivatives into cephalosporins that pr...
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ژورنال
عنوان ژورنال: Journal of Chemical Sciences
سال: 2007
ISSN: 0253-4134,0973-7103
DOI: 10.1007/s12039-007-0034-4