{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2023,10,24]],"date-time":"2023-10-24T11:42:20Z","timestamp":1698147740441},"reference-count":9,"publisher":"Wiley","issue":"6","license":[{"start":{"date-parts":[[2004,10,25]],"date-time":"2004-10-25T00:00:00Z","timestamp":1098662400000},"content-version":"vor","delay-in-days":4786,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Helvetica Chimica Acta"],"published-print":{"date-parts":[[1991,9,18]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The pentacyclic triterpenes <jats:bold>1a, b<\/jats:bold> and <jats:bold>2a, b<\/jats:bold> are isolated from extracts of <jats:italic>Euphorbia mellifera<\/jats:italic> Arr. Their structures, determined by X\u2010ray analysis, are supported in part by MS, NMR, and IR data. The skeleton differs from that of representatives of the lupane or hopane class by (<jats:italic>i<\/jats:italic>) an unusual arrangement of the substituents in the cyclopentane ring E, the Me group being on C(19) and the i\u2010Pr group in an angular position on C(17), and (<jats:italic>ii<\/jats:italic>) a <jats:italic>cis<\/jats:italic> D\/E ring junction. We propose to name Die unknown pentacyclic parent \u2018madeirane\u2019, thus <jats:bold>1a, b<\/jats:bold> and <jats:bold>2a, b<\/jats:bold> are <jats:italic>D<\/jats:italic>\u2010friedomadeir\u201014\u2010ene and <jats:italic>D<\/jats:italic>:<jats:italic>C<\/jats:italic>\u2010friedomadeir\u20107\u2010ene derivatives. The biosynthesis of these compounds may be rationalized <jats:italic>via<\/jats:italic> \u2018spirodammaranol\u2019\u2010cation intermediates <jats:bold>5<\/jats:bold> and <jats:bold>5\u2032<\/jats:bold> and madeiranol cation <jats:bold>6<\/jats:bold>, as outlined in <jats:italic>Scheme 2<\/jats:italic>.<\/jats:p>","DOI":"10.1002\/hlca.19910740622","type":"journal-article","created":{"date-parts":[[2004,12,28]],"date-time":"2004-12-28T12:06:13Z","timestamp":1104235573000},"page":"1329-1338","source":"Crossref","is-referenced-by-count":10,"title":["Madeiranes, a New Class of Pentacyclic Triterpenes: <i>D<\/i>\u2010Friedo\u2010madeir\u201014\u2010en\u20103\u03b2\u2010ol and \u20103\u2010one, <i>D<\/i>:<i>C<\/i>\u2010Friedomadeir\u20107\u2010en\u20103\u03b2\u2010ol and \u20103\u2010one"],"prefix":"10.1002","volume":"74","author":[{"given":"Maria\u2010Jos\u00e9 Umbelino","family":"Ferreira","sequence":"first","affiliation":[]},{"given":"Ana M.","family":"Lobo","sequence":"additional","affiliation":[]},{"given":"Caroline A.","family":"O'Mahoney","sequence":"additional","affiliation":[]},{"given":"David J.","family":"Williams","sequence":"additional","affiliation":[]},{"given":"Hugo","family":"Wyler","sequence":"additional","affiliation":[]}],"member":"311","published-online":{"date-parts":[[2004,10,25]]},"reference":[{"key":"e_1_2_1_2_2","unstructured":"M. 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Commun.1973 367.","DOI":"10.1055\/s-1973-22218"}],"container-title":["Helvetica Chimica Acta"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fhlca.19910740622","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/hlca.19910740622","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,23]],"date-time":"2023-10-23T19:09:47Z","timestamp":1698088187000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/hlca.19910740622"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1991,9,18]]},"references-count":9,"journal-issue":{"issue":"6","published-print":{"date-parts":[[1991,9,18]]}},"alternative-id":["10.1002\/hlca.19910740622"],"URL":"https:\/\/doi.org\/10.1002\/hlca.19910740622","archive":["Portico"],"relation":{},"ISSN":["0018-019X","1522-2675"],"issn-type":[{"value":"0018-019X","type":"print"},{"value":"1522-2675","type":"electronic"}],"subject":[],"published":{"date-parts":[[1991,9,18]]}}}