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Conformations of highly hindered aryl ethers. XXI—fragementation paths involving intramolecular π‐complexes and cyclizations in the mass spectra of 2,4‐dinitrophenyl 2′‐alkylphenyl ethers
Author(s) -
Jáuregui J. Fernando,
Lehmann F. Pedro A.
Publication year - 1974
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210090108
Subject(s) - chemistry , intramolecular force , steric effects , dinitrophenyl , ether , fragmentation (computing) , aryl , mass spectrum , stereochemistry , nitro , medicinal chemistry , organic chemistry , ion , alkyl , computer science , antibody , immunology , biology , operating system
Abstract The mass spectrometric study of 2,4‐dinitrophenyl 2′‐R‐phenyl ethers (R H, Me, Et, i‐Pr, tert‐Bu) showed that (1) fragmentation proceeds differently from unsubstituted and 4‐nitro‐substituted diphenyl ethers; (2) important fragmentation routes involve interannular migrations and cyclizations; (3) these occur between two groups ortho to the ether linkage while the ethers are in unfavorable endo, endo twist conformations; (4) the observed interannular interactions can be ustified by the existence in these compounds of an intramolecular π‐complex which stabilizes the sterically unfavorable conformation and explains the observed fragmentations.