Nakayama, Taku published the artcilePalladium-Catalyzed Dehydrogenative Synthesis of Imidazoquinolines in Water, Quality Control of 6214-45-5, the main research area is imidazoquinoline preparation green chem; benzylic alc diaminoquinoline dehydrogenative coupling reaction palladium catalyst.
A synthesis of imidazoquinolines I (R = Me, iso-Bu, Ph, etc.; Ar = Ph, 3-fluorophenyl, naphthalen-1-yl, etc.) via dehydrogenative coupling of 3,4-diaminoquinolines II with benzylic alcs. ArCH2OH utilizing π-benzylpalladium(II) system in water was reported. Readily available benzylic alcs. initially undergo catalytic dehydrogenation to form benzaldehydes, which are then reacted with 3,4-diaminoquinolines II via sequential cyclocondensation/aromatization, leading to the formation of imidazoquinolines I. This exptl. simple and practical one-pot procedure provides direct access to the desired products I without adding strong bases, toxic oxidants or other additives. Several experiments were carried out toward an understanding of the reaction mechanism to propose plausible catalytic cycles. The dehydrogenative coupling was found to be first order with respect to the benzyl alc. and Pd catalyst, and zero order with respect to the 3,4-diaminoquinoline substrate. A kinetic isotope effect of 3.1 was observed by sep. determining the reaction rates of benzyl alc. and benzyl-α,α-d2 alc. Water mols. accelerate the catalytic dehydrogenative coupling, suggesting that they act as a proton donor to activate the benzylic alcs. by a hydrogen-bonding network.
Asian Journal of Organic Chemistry published new progress about Aralkyl alcohols Role: RCT (Reactant), RACT (Reactant or Reagent). 6214-45-5 belongs to class alcohols-buliding-blocks, name is (4-Butoxyphenyl)methanol, and the molecular formula is C11H16O2, Quality Control of 6214-45-5.
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