Search results for "Semisynthesis"
showing 10 items of 13 documents
A Short and Improved Synthesis of the Antiprotozoal Abietane Diterpenoid (–)-Sugikurojin A
2016
An efficient and straightforward semisynthesis of the antiprotozoal abietane diterpenoid (–)-sugikurojin A, starting from the readily available methyl ester of callitrisic acid (4-epi-dehydroabietic acid) isolated from sandarac resin, is reported. This optimized semisynthetic route provides a convenient source of the antiprotozoal compound, in four steps from methyl callitrisate in 50% overall yield, for further biological studies.
Synthesis and evaluation of diverse thio avarol derivatives as potential UVB photoprotective candidates.
2007
Semisynthesis of 13 new thio avarol derivatives (4-16) and in vitro evaluation on the photodamage response induced by UVB irradiation are described. Their ability to inhibit NF-kappaB activation and TNF-alpha generation in HaCaT cells as well as their antioxidant capacity in human neutrophils has also been studied. Among them we have identified two monophenyl thio avarol derivatives (4-5) lacking cytotoxicity which can be considered promising UVB photoprotective agents through the potent inhibition of NF-kappaB activation with a mild antioxidant pharmacological profile.
Acetylcholinesterase and antioxidant evaluation of C18-functionalized ferruginol analogues
2019
Nearly 200 years ago, the study of the chemistry of terpenoids started with the analysis of turpentine oil, investigating the first resin acid, abietic acid from pine oleoresin.[1] Abietic acid occurs in plants of the genus Abies and is the first member of a class of plant metabolites, the abietane-type diterpenoids. They are characterized by a tricyclic ring system and have shown a wide range of chemical diversity and biological activity. [2,3] Medicinal chemists have studied derivatives of two readily available materials such as dehydroabietic acid and dehydroabietylamine. [3] To date, there is only one commercial drug, Ecabet® [ecabet sodium], based on abietanes, which is used for the tr…
New antitumoral acetogenin ‘Guanacone type’ derivatives: Isolation and bioactivity. Molecular dynamics simulation of diacetyl-guanacone
2007
We describe herein the isolation and semisynthesis of four acetogenin derivatives (1-4) as well as their ability to inhibit the mitochondrial respiratory chain and several tumor cell lines. In addition, four nanoseconds (ns) of MD simulation of compound 4, in a fully hydrated POPC bilayer, is reported.
Enantiospecific semisynthesis of (+)-almuheptolide-A, a novel natural heptolide inhibitor of the mammalian mitochondrial respiratory chain.
1998
The development of novel styryl lactone derivatives as bioactive compounds and the semisynthesis of both 4,5-dialkoxylated eight-membered-ring lactones with a heptolide skeleton (almuheptolide-A (1) type) and 7-alkoxylated delta-lactones with a saturated furanopyrone skeleton (etharvensin (8) type) have been successfully achieved from the chiral unsaturated alpha-pyrone altholactone (7). This new method is a direct and one-step enantiospecific alkoxylation of altholactone (7) in concentrated acid medium, followed by formation of the eight-membered-ring zeta-lactone. The reaction mechanism operating in the synthesis of the heptolide skeleton is postulated to be a direct Michael-type addition…
A promising camptothecin derivative: Semisynthesis, antitumor activity and intestinal permeability.
2014
Oral administration of camptothecin (Cm) derivatives and other antitumoral agents is being actively developed in order to improve the quality of life of patients with cancer. Though several lipophilic derivatives of CPT have shown interesting oral bioavailability in preclinical and clinical studies, only Topotecan has been approved for this route of administration. Semisynthesis, antitumor activity, biological inhibition mechanism, and in situ intestinal permeability of 9, 10-[1,3]-Dioxinocamptothecin (CDiox), an unexplored CPT derivative, have been studied in this paper. The hexacyclic analog was as effective as Topotecan and CPT in different tumor cell lines, showing an expected similar a…
Semisynthesis of the Antiviral Abietane Diterpenoid Jiadifenoic Acid C from Callitrisic Acid (4-Epidehydroabietic Acid) Isolated from Sandarac Resin
2014
The semisynthesis of the antiviral abietane diterpenoid (+)-jiadifenoic acid C starting from the available methyl ester of callitrisic acid (4-epidehydroabietic acid) isolated from sandarac resin is reported. A protocol for the isolation of methyl callitrisate (methyl 4-epidehydroabietate) in gram quantities from sandarac resin is also described. Allylic C-17 oxygenation was introduced by regioselective dehydrogenation of the isopropyl group of methyl callitrisate with DDQ followed by selenium-catalyzed allylic oxidation. Ester hydrolysis afforded (+)-jiadifenoic acid C in 22% overall yield from methyl callitrisate. This semisynthetic route provides a convenient source of this anti-Coxsacki…
Preparation of 7-Alkoxylated Furanopyrones: Semisynthesis of (−)-Etharvensin, a New Styryl-Lactone from Goniothalamus arvensis
1997
A new furanopyrone derivative, (−)-etharvensin (1), was isolated from the stem bark of Goniothalamus arvensis. Semisynthesis of the 7-ethoxyfuranopyrone 1 was achieved by addition of EtOH in concentrated acid medium to the unsaturated α-pyrone (+)-altholactone (2). This protocol constitutes a novel, direct (single-step), and efficient method to prepare this class of bioactive compounds.
Semisynthesis of antitumoral acetogenins: SAR of functionalized alkyl-chain bis-tetrahydrofuranic acetogenins, specific inhibitors of mitochondrial c…
2000
The acetogenins of Annonaceae are known by their potent cytotoxic activity. In fact, they are promising candidates as a new future generation of antitumoral drugs to fight against the current chemiotherapic resistant tumors. The main target enzyme of these compounds is complex I (NADH:ubiquinone oxidoreductase) of the mitochondrial respiratory chain, a key enzymatic complex of energy metabolism. In an attempt to characterize the relevant structural factor of the acetogenins that determines the inhibitory potency against this enzyme, we have prepared a series of bis-tetrahydrofuranic acetogenins with different functional groups along the alkyl chain. They comprise several oxo, hydroxylimino,…
Semisynthesis and cytotoxicity of styryl-lactone derivatives.
1999
The cytotoxicity and the cell-cycle action of altholactone (1), goniofufurone (2), and eight altholactone derivatives (5-12), were determined in vitro on L-1210 cells. Semisyntheses and structure-activity relationships of these compounds are described. The results of this study suggest that the cytotoxicity of altholactone (1), 11-nitro-altholactone (8), and 7-chloro-6,7-dihydroaltholactone (10) is due to the accumulation of the cells in the G2 + M phase of the cell cycle.