{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T10:38:16Z","timestamp":1775039896355,"version":"3.50.1"},"reference-count":25,"publisher":"Wiley","issue":"10","license":[{"start":{"date-parts":[[2011,10,17]],"date-time":"2011-10-17T00:00:00Z","timestamp":1318809600000},"content-version":"vor","delay-in-days":16,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Helvetica Chimica Acta"],"published-print":{"date-parts":[[2011,10]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Several 4\u2010azaphthalides (=furo[3,4\u2010<jats:italic>b<\/jats:italic>]pyridin\u20105(7<jats:italic>H<\/jats:italic>)\u2010ones) and 5\u2010azaisocoumarins (=5<jats:italic>H<\/jats:italic>\u2010pyrano[4,3\u2010<jats:italic>b<\/jats:italic>]pyridin\u20105\u2010ones) were prepared through a tandem heterogeneous Pd\/C\u2010mediated <jats:italic>Sonogashira<\/jats:italic> coupling and a 5\u2010<jats:italic>exo\u2010dig<\/jats:italic> or 6\u2010<jats:italic>endo\u2010dig<\/jats:italic> intramolecular cyclization of 2\u2010bromonicotinic acid (=2\u2010bromopyridine\u20103\u2010carboxyclic acid) with various ethynylarenes or 3\u2010ethynylthiophene. In the presence of Pd\/C\uf8ffPh<jats:sub>3<\/jats:sub>P\uf8ffCuI and Et<jats:sub>3<\/jats:sub>N in dry dioxane under Ar at 90\u00b0, a mixture of 4\u2010azaphthalides (usually the major product) and 5\u2010azaisocoumarins was obtained after 3.5\u2005h under normal heating (<jats:italic>Schemes\u20053<\/jats:italic> and <jats:italic>4<\/jats:italic>; <jats:italic>Tables\u20051<\/jats:italic> and <jats:italic>2<\/jats:italic>). This mixture of compounds was also obtained with the same catalytic system under microwave (MW) irradiation in only 25\u2005min (<jats:italic>Tables\u20053<\/jats:italic> and <jats:italic>4<\/jats:italic>). The 1\u2010ethynyl\u20103\u2010methoxybenzene gave on heating only the corresponding 4\u2010azaphthalide (<jats:italic>Table\u20052<\/jats:italic>), while under MW irradiation, both the 5\u2010<jats:italic>exo\u2010dig<\/jats:italic> and the 6\u2010<jats:italic>endo\u2010dig<\/jats:italic> products were obtained (<jats:italic>Table\u20054<\/jats:italic>). For the 3\u2010ethynylthiophene, the regioselectivity for the corresponding 4\u2010azaphthalide was achieved with both methods (<jats:italic>Tables\u20052<\/jats:italic> and <jats:italic>4<\/jats:italic>). Although the yields and the regioselectivity of the reaction generally remained the same with both methods, the use of MW allowed us to obtain the corresponding products in a shorter reaction time. From 4\u2010ethynyl\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010dimethylaniline (=4\u2010ethynyl\u2010<jats:italic>N<\/jats:italic>,<jats:italic>N<\/jats:italic>\u2010dimethylbenzenamine), the corresponding 4\u2010azaphthalide and 5\u2010isocoumarin were only obtained under MW irradiation (<jats:italic>Tables\u20052<\/jats:italic> and <jats:italic>4<\/jats:italic>). To the best of our knowledge, it is the first time that this kind of tandem reaction was applied to a pyridine derivative giving the corresponding 4\u2010azaphthalides and 5\u2010azaisocoumarins which are easily separated and may both show biological activity.<\/jats:p>","DOI":"10.1002\/hlca.201100060","type":"journal-article","created":{"date-parts":[[2011,10,17]],"date-time":"2011-10-17T11:08:39Z","timestamp":1318849719000},"page":"1792-1801","source":"Crossref","is-referenced-by-count":5,"title":["Tandem Palladium\/Charcoal\u2010Copper(I) Iodide (Pd\/C\u2010CuI) Catalyzed <i>Sonogashira<\/i> Coupling and Intramolecular Cyclization from 2\u2010Bromonicotinic Acid (=2\u2010Bromopyridine\u20103\u2010carboxylic Acid) and Ethynylarenes to 4\u2010Azaphthalides (=Furo[3,4\u2010<i>b<\/i>]pyridin\u20105(7<i>H<\/i>)\u2010ones) and 5\u2010Azaisocoumarins (=5<i>H<\/i>\u2010Pyrano[4,3\u2010<i>b<\/i>]pyridin\u20105\u2010ones)"],"prefix":"10.1002","volume":"94","author":[{"given":"Agathe","family":"Begouin","sequence":"first","affiliation":[]},{"given":"Maria\u2010Jo\u00e3o ;R. P.","family":"Queiroz","sequence":"additional","affiliation":[]}],"member":"311","published-online":{"date-parts":[[2011,10,17]]},"reference":[{"key":"e_1_2_1_1_2","doi-asserted-by":"publisher","DOI":"10.1021\/np030146m"},{"key":"e_1_2_1_1_3","doi-asserted-by":"publisher","DOI":"10.1016\/j.bmcl.2005.06.031"},{"key":"e_1_2_1_1_4","doi-asserted-by":"publisher","DOI":"10.1016\/j.bmc.2004.10.018"},{"key":"e_1_2_1_2_2","doi-asserted-by":"publisher","DOI":"10.1021\/cr60229a002"},{"key":"e_1_2_1_2_3","doi-asserted-by":"publisher","DOI":"10.1248\/cpb.29.2491"},{"key":"e_1_2_1_2_4","doi-asserted-by":"publisher","DOI":"10.1271\/bbb1961.45.1675"},{"key":"e_1_2_1_2_5","doi-asserted-by":"publisher","DOI":"10.1139\/v86-149"},{"key":"e_1_2_1_2_6","doi-asserted-by":"publisher","DOI":"10.1139\/v86-150"},{"key":"e_1_2_1_2_7","doi-asserted-by":"publisher","DOI":"10.1139\/v87-130"},{"key":"e_1_2_1_2_8","doi-asserted-by":"publisher","DOI":"10.1021\/jo971622e"},{"key":"e_1_2_1_2_9","first-page":"372","volume":"40","author":"Hussain M. 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