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 SM ISO690:2012GÎRBU, Vladilena, UNGUR, Nikon, KULCIŢKI, Veaceslav, RENAUD, Philippe. Radical transformations of ENT-isocopalic diterpenes. In: Achievements and perspectives of modern chemistry, 9-11 octombrie 2019, Chişinău. Chisinau, Republic of Moldova: Tipografia Academiei de Ştiinţe a Moldovei, 2019, p. 220. ISBN 978-9975-62-428-2. |
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| Achievements and perspectives of modern chemistry 2019 | ||||||
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Conferința "International Conference "Achievements and perspectives of modern chemistry"" Chişinău, Moldova, 9-11 octombrie 2019 | ||||||
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Spongiane diterpenoids are natural compounds isolated form sponges, corals and marine mollusks. Most of them play a key role as physiological mediators and are of interest for potential applications as therapeutic agents. These diterpenoids possess biological properties including antifungal, anti-inflammatory, cytotoxic and anti-HIV activities [1, 2]. Methyl ent-isocopalate, the tricyclic diterpene of the spongian family is used as a good precursor in the total synthesis of natural compounds [3]. It was obtained in 61% overall yield, starting from sclareol, a commercially available and inexpensive compound. Carboazidation of methyl ent-isocopalate with ethyl iodoacetate and phenylsulfonyl azide under DTBHN initiation conditions resulted in the formation of azide 2 in 55% yield (Figure). The relative stereochemistry of azide 2 was determined based on NOESY NMR data.formulaFigure. Radical carboazidation of diterpenes. Reagents and conditions: a. ICH2CO2Et (2 equiv.), 3-PySO2N3 (3 equiv.), Bu6Sn2 (1.5 equiv.), DTBHN (0.03 equiv.), benzene, 10 h, delta; b. imidazole (4 equiv.), TBDMSCl (2 equiv.), DMF, r.t. overnight; c. ICH2CO2Et (2 equiv.), PhSO2N3 (3 equiv.), Bu6Sn2 (1.5 equiv.), DTBHN (0.03 equiv.), benzene, 10 h, delta; d. TBAF (3 equiv.), THF, r.t., overnight. e. H2, Pd/C, EtOAc, r.t., 48 h. The 12 a-hydroxy-ent-isocopal-13(16)-en-15-oic acid 3 was synthesized from isocopalic ester 1 according to the known procedure [4]. Then, compound 3 was transformed via the TBDS ether 4 into lactam 5 over 3 steps in a 63% total yield. The key step in this sequence was the carboazidation of the exomethylenic double bond, followed by reduction of the azide moiety, which triggered a spontaneous lactamization. The introduced heteroatomic functional groups represent new structural motifs integrated into the isocopalic framework and their effect on the biological properties is currently under investigation. |
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<?xml version='1.0' encoding='utf-8'?> <resource xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns='http://datacite.org/schema/kernel-3' xsi:schemaLocation='http://datacite.org/schema/kernel-3 http://schema.datacite.org/meta/kernel-3/metadata.xsd'> <creators> <creator> <creatorName>Gîrbu, V.M.</creatorName> <affiliation>Institutul de Chimie, Moldova, Republica</affiliation> </creator> <creator> <creatorName>Ungur, N.D.</creatorName> <affiliation>Institutul de Chimie, Moldova, Republica</affiliation> </creator> <creator> <creatorName>Kulciţki, V.N.</creatorName> <affiliation>Institutul de Chimie, Moldova, Republica</affiliation> </creator> <creator> <creatorName>Renaud, P.</creatorName> <affiliation>Universitatea din Berna, Elveţia, Elveţia</affiliation> </creator> </creators> <titles> <title xml:lang='en'>Radical transformations of ENT-isocopalic diterpenes</title> </titles> <publisher>Instrumentul Bibliometric National</publisher> <publicationYear>2019</publicationYear> <relatedIdentifier relatedIdentifierType='ISBN' relationType='IsPartOf'>978-9975-62-428-2</relatedIdentifier> <dates> <date dateType='Issued'>2019</date> </dates> <resourceType resourceTypeGeneral='Text'>Conference Paper</resourceType> <descriptions> <description xml:lang='en' descriptionType='Abstract'><p>Spongiane diterpenoids are natural compounds isolated form sponges, corals and marine mollusks. Most of them play a key role as physiological mediators and are of interest for potential applications as therapeutic agents. These diterpenoids possess biological properties including antifungal, anti-inflammatory, cytotoxic and anti-HIV activities [1, 2]. Methyl ent-isocopalate, the tricyclic diterpene of the spongian family is used as a good precursor in the total synthesis of natural compounds [3]. It was obtained in 61% overall yield, starting from sclareol, a commercially available and inexpensive compound. Carboazidation of methyl ent-isocopalate with ethyl iodoacetate and phenylsulfonyl azide under DTBHN initiation conditions resulted in the formation of azide 2 in 55% yield (Figure). The relative stereochemistry of azide 2 was determined based on NOESY NMR data.</p><p>formula</p><p>Figure. Radical carboazidation of diterpenes. Reagents and conditions: a. ICH2CO2Et (2 equiv.), 3-PySO2N3 (3 equiv.), Bu6Sn2 (1.5 equiv.), DTBHN (0.03 equiv.), benzene, 10 h, delta; b. imidazole (4 equiv.), TBDMSCl (2 equiv.), DMF, r.t. overnight; c. ICH2CO2Et (2 equiv.), PhSO2N3 (3 equiv.), Bu6Sn2 (1.5 equiv.), DTBHN (0.03 equiv.), benzene, 10 h, delta; d. TBAF (3 equiv.), THF, r.t., overnight. e. H2, Pd/C, EtOAc, r.t., 48 h. The 12 a-hydroxy-ent-isocopal-13(16)-en-15-oic acid 3 was synthesized from isocopalic ester 1 according to the known procedure [4]. Then, compound 3 was transformed via the TBDS ether 4 into lactam 5 over 3 steps in a 63% total yield. The key step in this sequence was the carboazidation of the exomethylenic double bond, followed by reduction of the azide moiety, which triggered a spontaneous lactamization. The introduced heteroatomic functional groups represent new structural motifs integrated into the isocopalic framework and their effect on the biological properties is currently under investigation.</p></description> </descriptions> <formats> <format>application/pdf</format> </formats> </resource>
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