Studier av 2-cykloaminoindener speciellt med hänsyn till prototropa omlagringar

• Main Author: Edlund, Ulf
• Format: Doctoral Thesis
• Language: English
• Published: Umeå universitet, Kemiska institutionen 1974
• Subjects: Chemical Sciences; Kemi
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-141125

This thesis is a short review of six papers (Papers 1-6,page 5) concerning studies of enamines from 2-indanones. The unusuallystable 2-(N-pyrrolidyl)indene has been studied (Paper 2 ). As a base catalyst this enamine rearranges 1-methylindene to 3-methylindene with a lower rate constant compared with triethylamine. During this 1 ,3-prototropic rearrangement no hydrogen exchangewas observed (Paper 1). Special attention has been drawn to 1 ,3-rearrangements ofalkyl-substituted enamines of 2-indanone. Prom 1-methyl-2-indanone, which was most conveniently prepared by oxidation of the correspondingindene, a series of enamines has been prepared with varyingamine components. A study of the kinetic control of the formation of these enamines showed that the less substituted double-bondisomer was formed more rapidly than the other form. Furthermore, the nature of the amine group has a significant influence on the composition of the equilibrium mixture observed, but the isomericratios obtained were unexpected in the light of earlier investigationsof enamines from 2-methylcyclohexanone (Paper l). A 13C NMR study of these 2-cycloaminoindenes showed that introduction of a 1-methyl substituent caused a decrease in overlap but the magnitude of this perturbation was almost independent of the variation of the amine component. Furthermore, when using pyrrolidineor hexamethyleneimine as amine parts this decrease in overlapwas of a comparable magnitude with the diminished conjugationnoted in the 3-methyl isomers. However, when piperidine or morpholinewas used the decreased delocalization was more pronounced inthe 3-methyl tautomers compared with the 1-methyl analogues (Paper6). One isomer, 1-methyl-2-(N-piperidyl)indene, has been shown toundergo base- as well as acid-catalyzed 1,3-tautomerizations inpyridine solvent. The isomerization rates using 1,4-diazabicyclo-(2.2.2.)octane or quinuclidine as base catalysts were considerably slower than the rate of the acid-catalyzed reaction or the basecatalyzedrearrangement rates involving alkyl-substituted indenesas substrates. This retarding effect, caused by the amine group, is in agreement with differences in pKA values obtained via simpleHückel calculation (Paper 4). The reaction between pyrrolidine and 1-(2-indanylidene)indan--2-one has been investigated. Two possible mechanisms were sugges-ted for the formation of products consisting of a linear dienamineand an indenyl-substituted enamine (9:1). In the main productisolated by recrystallization, the indenyl substituent was shownto be twisted out of conjugation. This dienamine also underwentacid-catalyzed isomerization to form the enamine product (Paper 3). Convenient syntheses of the pharmacologically interestingN-substituted 2-aminoindanes have also been described. The perchloratesalts of the enamines were treated with sodium borohydride in methanol to afford the desired products (Paper 5). === <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1974</p> === digitalisering@umu