{"id":{"repo_id":"rice","oai_identifier":"oai:repository.rice.edu:1911/19311"},"canonical_url":"https://search.dev.ndltd.org/etd/rice/oai:repository.rice.edu:1911/19311","repository":{"repo_id":"rice","name":"Rice University","base_url":"https://repository.rice.edu/server/oai/request"},"display":{"title":"Studies on complex pyridine alkaloids: Total synthesis of cystodytin J, diplamine, shermilamine B and of Micrococcin P1","abstract":"Concise, efficient total syntheses of cystodytin J, diplamine and shermilamine B have been accomplished. These cytotoxic marine alkaloids display a novel pyridoacridine architecture that was readily assembled by a combination of two new processes developed in our laboratory: a pyridine-forming reaction and a photochemical insertion of a triplet nitrene into a C-H bond. The overall yield of diplamine is 12% over 7 steps. The synthesis of shermilamine B involves 11 steps with the overall yield of 8%. The first total synthesis of the antitumor agent, Micrococcin P1, a member of the biologically important family of thiostrepton antibiotics, is also described. Central to the success of this endeavor was the development of a greatly improved Hantzsch-type pyridine forming reaction. Additional chemical technologies featured in this synthesis include the use of transformations that remove the need for extensive purification of the various intermediates, the use of specially protected threonine units as precursors to the dehydroaminoacid components of micrococcin, extensive use of chemoselective thionation reactions in the presence of multiple reactive functionality, minimal protection, and closure of a 26 member ring. The longest linear sequence involves 23 steps and the overall yield along this pathway is 5.7%","abstract_html":"Concise, efficient total syntheses of cystodytin J, diplamine and shermilamine B have been accomplished. These cytotoxic marine alkaloids display a novel pyridoacridine architecture that was readily assembled by a combination of two new processes developed in our laboratory: a pyridine-forming reaction and a photochemical insertion of a triplet nitrene into a C-H bond. The overall yield of diplamine is 12% over 7 steps. The synthesis of shermilamine B involves 11 steps with the overall yield of 8%. The first total synthesis of the antitumor agent, Micrococcin P1, a member of the biologically important family of thiostrepton antibiotics, is also described. Central to the success of this endeavor was the development of a greatly improved Hantzsch-type pyridine forming reaction. Additional chemical technologies featured in this synthesis include the use of transformations that remove the need for extensive purification of the various intermediates, the use of specially protected threonine units as precursors to the dehydroaminoacid components of micrococcin, extensive use of chemoselective thionation reactions in the presence of multiple reactive functionality, minimal protection, and closure of a 26 member ring. The longest linear sequence involves 23 steps and the overall yield along this pathway is 5.7%","abstract_has_math":false,"creators":["Shen, Yongchun"],"institution":"Rice University","degree_name":"Doctor of Philosophy","degree_level":"Doctoral","degree_discipline":"Natural Sciences","degree_department":null,"school":null,"contributors":[],"advisors":["Ciufolini, Marco A."],"committee_chairs":[],"committee_members":[],"year":1998,"date_issued":"1998","date_published":"1998","updated_at":"2026-07-24T04:10:24Z","subjects":["Organic chemistry","Pharmaceutical chemistry"],"languages":["eng"],"rights":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/1911/19311","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Ciufolini, Marco A."]},{"key":"dc:creator","label":"Author","values":["Shen, Yongchun"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2009-06-04T06:27:06Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2009-06-04T06:27:06Z"]},{"key":"dc:date.issued","label":"Date","values":["1998"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Natural Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Rice University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Organic chemistry","Pharmaceutical chemistry"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/1911/19311"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Concise, efficient total syntheses of cystodytin J, diplamine and shermilamine B have been accomplished. These cytotoxic marine alkaloids display a novel pyridoacridine architecture that was readily assembled by a combination of two new processes developed in our laboratory: a pyridine-forming reaction and a photochemical insertion of a triplet nitrene into a C-H bond. The overall yield of diplamine is 12% over 7 steps. The synthesis of shermilamine B involves 11 steps with the overall yield of 8%. The first total synthesis of the antitumor agent, Micrococcin P1, a member of the biologically important family of thiostrepton antibiotics, is also described. Central to the success of this endeavor was the development of a greatly improved Hantzsch-type pyridine forming reaction. Additional chemical technologies featured in this synthesis include the use of transformations that remove the need for extensive purification of the various intermediates, the use of specially protected threonine units as precursors to the dehydroaminoacid components of micrococcin, extensive use of chemoselective thionation reactions in the presence of multiple reactive functionality, minimal protection, and closure of a 26 member ring. The longest linear sequence involves 23 steps and the overall yield along this pathway is 5.7%"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Studies on complex pyridine alkaloids: Total synthesis of cystodytin J, diplamine, shermilamine B and of Micrococcin P1"]}]}],"canonical_facts":{"dc:contributor.advisor":["Ciufolini, Marco A."],"dc:creator":["Shen, Yongchun"],"dc:date.accessioned":["2009-06-04T06:27:06Z"],"dc:date.available":["2009-06-04T06:27:06Z"],"dc:date.issued":["1998"],"dc:description.abstract":["Concise, efficient total syntheses of cystodytin J, diplamine and shermilamine B have been accomplished. These cytotoxic marine alkaloids display a novel pyridoacridine architecture that was readily assembled by a combination of two new processes developed in our laboratory: a pyridine-forming reaction and a photochemical insertion of a triplet nitrene into a C-H bond. The overall yield of diplamine is 12% over 7 steps. The synthesis of shermilamine B involves 11 steps with the overall yield of 8%. The first total synthesis of the antitumor agent, Micrococcin P1, a member of the biologically important family of thiostrepton antibiotics, is also described. Central to the success of this endeavor was the development of a greatly improved Hantzsch-type pyridine forming reaction. Additional chemical technologies featured in this synthesis include the use of transformations that remove the need for extensive purification of the various intermediates, the use of specially protected threonine units as precursors to the dehydroaminoacid components of micrococcin, extensive use of chemoselective thionation reactions in the presence of multiple reactive functionality, minimal protection, and closure of a 26 member ring. The longest linear sequence involves 23 steps and the overall yield along this pathway is 5.7%"],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/1911/19311"],"dc:language.iso":["eng"],"dc:rights":["Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder."],"dc:subject":["Organic chemistry","Pharmaceutical chemistry"],"dc:title":["Studies on complex pyridine alkaloids: Total synthesis of cystodytin J, diplamine, shermilamine B and of Micrococcin P1"],"dc:type":["Thesis"],"thesis:degree_discipline":["Natural Sciences"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["Rice University"]},"updated_at":"2026-07-24T04:10:24Z"}