To optimize these fluorescent probes, the electron-donating p-dimethylamino group and electron-accepting cyano group
were introduced to construct a compound with a donor-[pi]-acceptor structure (Figure 1).
The IR spectrum showed a strong absorption band at 1732 [cm.sup.-1] corresponding to lactonic carbonyl group and the disappearance of the cyano group
. Also the structure was confirmed by elemental analysis; 1H-NMR spectrum showed a singlet at [delta] 12.52 ppm of NH, a doublet at [delta] 7.162-7.136 ppm and [delta] 6.84-6.81 ppm of aromatic protons, a singlet at [delta] 4.7 ppm of benzylic proton, and a singlet at [delta] 3.68 ppm of three protons for OC[H.sub.3] group.
The desired transformations were investigated using the conditions reported by Konig , by coupling the substrates 1 and 1a with the inorganic cyano group
using CuCN surprisingly, contrary to the results revealed by Konig, a marked improvement in the isolated yields (90 and 85 %) were observed following the 18 and 20 h of irradiation under 7 W fluorescent bulb (Table 2, entries 2, 4).
(23.) Yan, H, Wang, H, Cheng, J, Fang, Z, Wang, H, "Effect of Iron Acetylacetonate on the Crosslink Structure, Thermal and Flammability Properties of Novel Aromatic Diamine-Based Benzoxazines Containing Cyano Group
." RSC Adv., 5 (24) 18538-18545 (2015)
2 showed several characteristic absorption peaks at 2233 and 1651 [cm.sup.-1] attributed to the stretching vibration of cyano group
(C [equivalent to] N) and carbonyl (C=O), respectively, which correlated well with the chemical structure of m-PAEK-CN shown in Fig.
The peak of Cyano group
is visible at [delta] = 119.5.
It has been found that all the compounds were found to be more active against all bacterial strains than ampicillin whereas compounds 6d and 6e substituted with chloro and cyano group
were found to most potent.
The highest oxygen content was 19.8% at 180[degrees]C, which indicated that the hydrolysis degree of cyano group
was the deepest under this condition.
The column's ligand design incorporates an extended alkyl chain spacer between the silica surface and cyano group
, which gives extra phase stability and increased column lifetime.
Although direct introduction of the methyl group at C24 by opening the 23,24-epoxide was not successful, a cyano group
was introduced specifically at C24 to give 22R,23R-diol (54).
Bromoxynil-degrading enzymes degrade the cyano group
of bromoxynil into a carboxyl group.