9-Iodoso-10-phenanthroate: Structure and Phosphorolytic Properties of a Nonplanar Iodoxolone
摘要:
9-Iodoso-10-phenanthroic acid (IPA-OK) was prepared from 9-cyanophenanthrene in a four-step, 44% overall yield synthesis, featuring cyano-directed ortho lithiation/iodination as the key step. An X-ray crystal structure showed that TPA-OH exists in a phenanthroiodoxol-3(1H)-one valence tautomeric form, 14-OH, characterized by T-shaped geometry at iodine, strong WO steric interactions between the peri-H atoms and the carbonyl and iodoso oxygen atoms, a ''short'' endocyclic I-O bond, well-differentiated carbonyl and endocyclic C-O bond lengths, and nonplanarity in both the iodoxolone and phenanthrene rings (Figures 1 and 2). IPA-OH was an excellent catalyst for the cleavage of p-nitrophenyl diphenyl phosphate (PNPDPP) in aqueous micellar cetyltrimethylammonium chloride (CTACl) solutions at pH 8 and 25 degrees C: 1 x 10(-5) M PNPDPP was cleaved by 1 x 10(-4) M IPA-OH in 3.5 x 10(-4) M CTACl with k(psi) = 0.38 s(-1). Experiments in which [PNPDPP] > [IPA-OH] demonstrated that the catalyst ''turned over''; hydrolysis of the putative phosphorylated IPA-OH intermediate was rapid.
Functionalized 4-benzylated pyridines can be efficiently prepared by a transition-metal-freecross-coupling between various benzylic zinc chlorides and substituted 4-cyanopyridines in THF/DMPU under microwave irradiation (40 °C, 0.5–1.5 h). Selective benzylations on polycyano-aromatics have also been achieved under these mild conditions. We also report a novel oxidative nucleophilic substitution of
Palladium-Catalyzed Ullmann Cross-Coupling of β-Iodoenones and β-Iodoacrylates with <i>o</i>-Halonitroarenes or <i>o</i>-Iodobenzonitriles and Reductive Cyclization of the Resulting Products To Give Diverse Heterocyclic Systems
作者:Faiyaz Khan、Michael Dlugosch、Xin Liu、Marium Khan、Martin G. Banwell、Jas S. Ward、Paul D. Carr
DOI:10.1021/acs.orglett.8b01015
日期:2018.5.4
palladium-catalyzed Ullmann cross-coupling of β-iodoenones and β-iodoacrylates such as 5 (X = I) with o-halonitroarenes and o-iodobenzonitriles including 2 affords products such as compound7. These can be engaged in a range of reductive cyclization reactions leading to heterocyclic frameworks such as 3,4-benzomorphan derivative 43.