ChemInform Abstract: Photoisomerization of 3‐Phenylnorbornadiene‐2‐carbaldehyde and Its Imines.

Abstract

ChemInform Abstract Photolysis of the title compound (I) affords the quadricyclane (II). The photolysis of the imines (III) is found to be dependent on the employed solvent. The quadricyclanes (IV) are produced only in protic solvents (no further details and no yields are given).

Norbornadiene–quadricyclane as an abiotic system for the storage of solar energy

“…The best catalytic activity was observed for molybdenum(VI) oxide, which is characterised by the highest metal electronegativity in this series. 72 Stirring of solutions of quadricyclanes 27 in heptane (5610 75 mol litre 71 ) with MoO 3 (0.2 ± 0.5 mg per 2 ml of a solution) results in the original norbornadienes 26 with a rate constant k = 10 72 ± 5610 73 s 71 at 291 K. Conditions for the repeated phototransformation 26 . 27 have been determined.…”

“…(Table 5). 67,69,71,72 By varying the electron-donating and electron-withdrawing substituents at the C=C double bond in norbornadienes 28, it became possible to shift the values of l max to 500 nm and l ae to 620 nm. Heterogeneous catalysis with Mo(VI) oxide described above proved to be efficient for the reverse reaction of the majority of quadricyclanes 29.…”

Solvent-induced E/Z(C=N)-isomerization of imines of some hydroxy-substituted formylcoumarins

“…Recently, 9 an equilibrium of four isomers of an open form of 5´ hydroxy 1,3,3 [1,4] oxazine] at -50 °C in CDCl 3 has been reported, two of which are the E and Z isomers with respect to the C=N bond, whereas two other, the E and Z isomers with re spect to the C=C bond.…”

“…For a number of aromatic and heteroaro matic hydroxyaldehyde and hydroxyketone derivatives, the corresponding isomerization transformations are studied in detail. [4][5][6][7] In the literature, the data on the isomerization trans formations of imines, derivatives of hydroxy substituted acylcoumarins, are absent. At the same time, the study of such transformations is of interest since many coumarin hydroxy and amino derivatives possess pronounced flu orescence, which is subjected to modulation due to the structural changes of the fluorophore molecules.…”

Z/E(C=C)-isomerization of coumarin enamines induced by organic solvents

“…4,5 Heteroaromatic imines are well known for their ability to undergo solvent driven isomerizations. [6][7][8][9] The solvatochromic behaviour of coumarin derivatives is of special interest due to their prominent fluorescence potential. 10 Earlier, we have found some imines of 8-formyl-7-hydroxycoumarin to undergo E/Z-isomerization around the C=N bond followed by fluorescence modulation.…”