Zur Stereochemie von 3‐Oxa‐7‐aza‐ und 3,7‐Diaza‐bicyclo[3,3,1]‐nonanonen

Abstract

Aus der kernresonanzspektroskopischen Untersuchung von substituierten 3-0xa-7-alkyl-7-azaund 3,7-Dialkyl-3,7diazi+bicyclo[3,3, Ikonanonen lassen sich RUckschliisse auf die Stereochemie dieser Verbindungen ziehen. Die an einzelnen dieser bicyclischen Verbindungen beobachtete Isomerie wird untersucht. Das NMR-Spektrum des Isomers 3b unterscheidet sich wesentlich von den Spektren der ubrigen Verbindungen, vor allem durch die Iniiquivalenz der Methylenprotonen der Xthoxycarbonylgruppen.Stereochemistry of 3-0xa-7-aza-and 3,7-Dioza-bicyclo[3,3,1] nonane-9anesConclusions about the stereochemistry of substituted 3-oxa-?-alkyl-7-aza and 3,7-dialkyl-3,7diazabicyclo[3,3,l]nonane-9-ones can be drawn from 'H-NMR-spectra. The isomerism which is observed in some of these bicyclic compounds is studied. The 'H-NMR-spectrum of the isomer 3b differs remarkably from the spectra of the other compounds, especially in the inequivalence of the methylene protons of the ethoxycarbonyl substituents. Haller und UnholzerArch. Pharrnaz.*) Aus der Dissertation R. Heyser-Langenfeld, BOM 1970.

Synthesis and Coordination Chemistry of Hexadentate Picolinic Acid Based Bispidine Ligands

“…The bispidine system is usually built up by two consecutive double Mannich reactions . The syntheses of piperidones 3 and 7 as well as of bispidones 4 and 8 have been described. To prevent ligand decomposition by a retro Mannich reaction, the bispidones 4 and 8 were reduced with sodium borohydride to the alcohols 5 and 9 , respectively. ,, The required secondary amine can be introduced directly at position N 3 by choosing ammonia in the first Mannich reaction (synthesis of the piperidone 7 ).…”

“…The standard piperidones 3 and 7 , the bispidones 4 and 8 , and the bispidols 5 and 9 were prepared according to slightly modified literature-known procedures . The tert -butyl ester protected picolinic acid derivative 2 was prepared in a two-step synthesis, whereby AIBN was used as the radical initiator for bromination of 1 instead of benzoyl peroxide.…”

Double Mannich reaction with ketones as a route to heterocyclic systems: A mini review

“…The synthesis of the asymmetric 3,7-DABCN-9-ones (84) [16, 39b, 66, 68-70] A variety of 3,7-DHBCN-9-ones with different substituents have been synthesized by a double Mannich reaction of 1-hetera-4-cyclohexanones with a primary amine and aldehyde [27,30,73]. The 3-oxa-7-azabicyclo[3.3.l]nonan-9-ones (90) [70,74,75] and 92a-d [76], have been prepared by double Mannich reaction with the appropriate tetrahydro-4H-pyran-4-one (Scheme 19).…”

“…The synthesis of the asymmetric 3,7‐DABCN‐9‐ones ( 84 ) [16, 39b, 66, 68–70], and the 2,4,6,8‐tetraaryl‐3,7‐DABCN‐9‐ones ( 86 ) [71] has been achieved by double Mannich reaction with the 4‐piperidones 83 and 85 , respectively (Scheme 17).…”

Etude structurale de deux oxazabicyclo [3.3.1.] nonanone: Mise en évidence des différences de conformation du système bicyclique

“…Haller et Unholzer (1972) ont étudié un certain nombre de diesters méthyliques ou éthyliques du type suivant :…”