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Solution‐Dimerization of 4‐Aryl‐1,4‐dihydropyridines
Author(s) -
Hilgeroth Andreas,
Baumeister Ute,
Heinemann Frank W.
Publication year - 2000
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(200001)2000:2<245::aid-ejoc245>3.0.co;2-2
Subject(s) - chemistry , aryl , irradiation , monomer , yield (engineering) , cleavage (geology) , photochemistry , crystal structure , crystallography , stereochemistry , organic chemistry , polymer , alkyl , physics , materials science , geotechnical engineering , fracture (geology) , nuclear physics , engineering , metallurgy
On irradiation at λ ≥ 270 nm solutions of 4‐aryl‐1,4‐dihydropyridines 1 yield cage dimers 2 as the main products beside small amounts of anti dimers 3 . 1 H‐NMR data and X‐ray crystal structure prove centrosymmetrical properties for both dimers with axially orientated 4‐aryl substituents. Irradiation with filtered light (λ > 313 nm) leads to syn and anti dimers 4 and 3 in nearly equal yields. The poor yields of anti dimers 3 on irradiation with unfiltered light are demonstrated to result from a partial cleavage back to their monomeric starting materials 1 .