<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-08-22T19:39:09Z</responseDate><request verb="GetRecord" identifier="oai:docta.ucm.es:20.500.14352/133371" metadataPrefix="rdf">https://docta.ucm.es/rest/oai/request</request><GetRecord><record><header><identifier>oai:docta.ucm.es:20.500.14352/133371</identifier><datestamp>2026-02-27T00:47:18Z</datestamp><setSpec>com_20.500.14352_14</setSpec><setSpec>col_20.500.14352_15</setSpec></header><metadata><rdf:RDF xmlns:rdf="http://www.openarchives.org/OAI/2.0/rdf/" xmlns:ow="http://www.ontoweb.org/ontology/1#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:ds="http://dspace.org/ds/elements/1.1/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/rdf/ http://www.openarchives.org/OAI/2.0/rdf.xsd">
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      <dc:title>Stereochemical issues related to the synthesis and reactivity of pyrazino[20 ,10 -5,1]pyrrolo[2,3-b]indole-1,4-diones</dc:title>
      <dc:creator>Caballero, Esmeralda</dc:creator>
      <dc:creator>Avendaño López, María Carmen</dc:creator>
      <dc:creator>Menéndez, J. Carlos</dc:creator>
      <dc:description>The cyclization of all four diastereoisomers of cyclo-(Trp-Ala) to the corresponding 3,5a,6,10b,11,11ahexahydro-2H-pyrazino[20 ,10 -5,1]pyrrolo[2,3-b]indoles is studied from the stereochemical point of view. Epimerization of the tryptophan stereocenter during the cyclization and during acylation reactions of the N-2 atom of the tetracyclic derivatives is discussed.</dc:description>
      <dc:date>2026-02-26T13:20:24Z</dc:date>
      <dc:date>2026-02-26T13:20:24Z</dc:date>
      <dc:date>1998</dc:date>
      <dc:type>journal article</dc:type>
      <dc:identifier>Caballero E, Avendaño C, Menéndez JC. Stereochemical issues related to the synthesis and reactivity of pyrazino[2′,1′-5,1]pyrrolo[2,3-b]indole-1,4-diones. Tetrahedron: Asymmetry. marzo de 1998;9(6):967-81. doi:10.1016/S0957-4166(98)00068-8</dc:identifier>
      <dc:identifier>10.1016/S0957-4166(98)00068-8</dc:identifier>
      <dc:identifier>https://hdl.handle.net/20.500.14352/133371</dc:identifier>
      <dc:identifier>https://dx.doi.org/10.1016/S0957-4166(98)00068-8</dc:identifier>
      <dc:language>eng</dc:language>
      <dc:relation>SAF-94-0517</dc:relation>
      <dc:relation>SAF-97-0143</dc:relation>
      <dc:rights>restricted access</dc:rights>
      <dc:publisher>Pergamon</dc:publisher>
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