TY  - JOUR
AB  - 2,19-Dioxo[3.3](3,3´)azobenzolophane (5) has been obtained in a total yield of 18% by way of CO insertion and cyclization of 1,2-bis[3-(bromomethyl)phenyl]-4,4-dimethyl-3,5-pyrazoli-dinedione (1) using CO 2(CO) 8 in acetonitrile followed by the removal of the N-protecting 4,4-dimethylmalonyl groups. 5 is obtained predominantly as the trans / trans isomer 5a and can be isomerized by irradiation with [lambda]=369 nm to a mixture of nearly equal amounts of the trans / trans, cis / trans, and cis / cis isomers 5a, 5b and 5c. The thermal isomerization back to 5a is slow but fast upon irradiation with [lambda]=443 nm.
DA  - 1990
DO  - 10.1002/cber.19901230827
KW  - Photoisomerism
KW  - Tetraaza [3.2.3.2] metacyclophane
KW  - Transition-metal carbonyl complexes
LA  - eng
IS  - 8
M2  - 1749
PY  - 1990
SN  - 0009-2940
SP  - 1749-1752
T2  - Chemische Berichte
TI  - A macrocyclic 2,19-dioxo[3.3](3,3´) azobenzolophane by transition-metal carbonyl complex-mediated CO insertion and cyclization
UR  - https://nbn-resolving.org/urn:nbn:de:0070-pub-17834663
Y2  - 2024-11-21T16:38:25
ER  -