500-64-1Relevant academic research and scientific papers
Biomimetic iterative method for polyketide synthesis
Akagawa, Kengo,Kudo, Kazuaki
supporting information, p. 8645 - 8648 (2017/08/10)
An iterative method for synthesizing polyketides was demonstrated, in which the chain elongation of a carboxylic acid was performed by decarboxylative dehydration condensation with a malonic acid half thioester. After transforming the resulting β-ketothioester into an appropriate form, the carboxylic acid functionality was regenerated for the next elongation step.
Pilot in Vivo Structure-Activity Relationship of Dihydromethysticin in Blocking 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone-Induced O6-Methylguanine and Lung Tumor in A/J Mice
Puppala, Manohar,Narayanapillai, Sreekanth C.,Leitzman, Pablo,Sun, Haifeng,Upadhyaya, Pramod,O'Sullivan, M. Gerard,Hecht, Stephen S.,Xing, Chengguo
, p. 7935 - 7940 (2017/10/06)
(+)-Dihydromethysticin was recently identified as a promising lung cancer chemopreventive agent, while (+)-dihydrokavain was completely ineffective. A pilot in vivo structure-activity relationship (SAR) was explored, evaluating the efficacy of its analogs in blocking 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced short-term O6-methylguanine and long-term adenoma formation in the lung tissues in A/J mice. Both results revealed cohesive SARs, demonstrating that the methylenedioxy functional group in DHM is essential while the lactone functional group tolerates modifications.
Characterisation of the broadly-specific O-methyl-transferase jerf from the late stages of jerangolid biosynthesis
Friedrich, Steffen,Hemmerling, Franziska,Lindner, Frederick,Warnke, Anna,Wunderlich, Johannes,Berkhan, Gesche,Hahn, Frank
, (2016/11/11)
We describe the characterisation of the O-methyltransferase JerF from the late stages of jerangolid biosynthesis. JerF is the first known example of an enzyme that catalyses the formation of a non-aromatic, cyclic methylenolether. The enzyme was overexpressed in E. coli and the cell-free extracts were used in bioconversion experiments. Chemical synthesis gave access to a series of substrate surrogates that covered a broad structural space. Enzymatic assays revealed a broad substrate tolerance and high regioselectivity of JerF, which makes it an attractive candidate for an application in chemoenzymatic synthesis with particular usefulness for late stage application on 4-methoxy-5,6-dihydro-2H-pyran-2-one-containing natural products.
A rapid and diverse construction of 6-substituted-5,6-dihydro-4-hydroxy-2- pyrones through double Reformatsky reaction
Mineno, Masahiro,Sawai, Yasuhiro,Kanno, Kazuaki,Sawada, Naotaka,Mizufune, Hideya
, p. 10921 - 10926 (2014/01/06)
A rapid and diverse synthesis of biologically important 6-substituted-5,6-dihydro-4-hydroxy-2-pyrones through a double Reformatsky reaction of aldehydes to δ-hydroxy-β-ketoesters followed by lactonization is described. Due to the high functional group tolerance and reaction site discrimination between aldehyde, nitrile, and ester groups in the substrate, the protocol can provide the dihydropyrones with bromo, nitro, carboxylic acid, and β-ketoester groups, which are suitable for the further derivatizations. Furthermore, the protocol has been successfully applied to the rapid total synthesis of naturally occurring Yangonin.
Synthesis of β-methoxyacrylate natural products based on box-Pd IIcatalyzed intermolecular methoxycarbonylation of alkynoles
Motodate, Satoshi,Kobayashi, Takuya,Fujii, Mikio,Mochida, Tomoyuki,Kusakabe, Taichi,Katoh, Shigeki,Akita, Hiroyuki,Kato, Keisuke
experimental part, p. 2221 - 2230 (2011/06/21)
Bis(oxazoline)-palladium(II) catalyzed carbonylation of homopropargyl alcohols afforded acyclic methoxyacrylate 2 and 6-membered lactone 3a-k in good combined yield. In the case of propargyl alcohols, 5-membered lactones 3p, 3q, 16 were obtained in moderate yields. The one-pot synthesis of kawa lactones 3a, 3r, 3s and formal synthesis of dihydroxycystothiazole A and dihydroxycystothiazole C are presented. To elucidate the stereochemistry of (+)-annularin G and (-)-annularin H, the first asymmetric syntheses of these natural products were achieved.
Towards synthesis of kavalactone derivatives
Amaral, Patrícia A.,Gouault, Nicolas,Roch, Myriam Le,Eifler-Lima, Vera L.,David, Michèle
supporting information; experimental part, p. 6607 - 6609 (2009/04/06)
Kavalactone derivatives were synthesized using a Heck reaction of the 4-methoxy-6-vinyl-5,6-dihydropyran-2-one with aryl iodides. The Suzuki-Miyaura reaction of an aryl boronic acid and (Z)-4-methoxy-6-(2-iodovinyl)-5,6-dihydropyran-2-one has also been successfully used to produce both Z and E isomers of lactones.
Efficient enantioselective hetero-diels-alder reaction of brassard's diene with aliphatic aldehydes: A one-step synthesis of (R)-(+)-kavain and (S)-(+)-dihydrokavain
Lin, Lili,Chen, Zhenling,Yang, Xu,Liu, Xiaohua,Feng, Xiaoming
supporting information; scheme or table, p. 1311 - 1314 (2009/04/06)
An efficient catalytic asymmetric hetero-Diels-Alder reaction of Brassard's diene with aliphatic aldehydes was reported The catalyst which was generated from (R)-BINOL, Ti(i-PrO)4, and 4-picolyl chloride hydrochloride, promoted the reaction smoothly to afford the corresponding α, β-unsaturated λ-lactone derivatives in moderate-to-good yields (46-79%) with high enantioselectivities (up to 88% ee) Natural products (R)-(+)-kavain (70% ee, > 99% ee after single re crystallization) and (S)-(+)-dihydrokavain (84% ee) were also prepared in one step by using this methodology.
Metathesis-based synthesis of 3-methoxy α,β-unsaturated lactones: total synthesis of (R)-kavain and of the C1-C6 fragment of jerangolid D
Pospí?il, Ji?í,Markó, István E.
, p. 1523 - 1526 (2008/09/19)
The total synthesis of (R)-kavain and of the C1-C6 fragment of jerangolid D has been achieved in nine and seven steps, respectively, from commercially available dimethyl d-malate. A metathesis reaction of vinyl ethers and a sulfoxide-modified Julia olefination have been employed as the key steps.
Application of the Cosford cross-coupling protocol for the stereoselective synthesis of (R)-(+)-goniothalamin, (R)-(+)-kavain and (S)-(+)-7,8-dihydrokavain
Sabitha, Gowravaram,Sudhakar,Yadav
, p. 8599 - 8602 (2007/10/03)
An efficient and versatile synthetic method has been developed and utilized for the stereoselective synthesis of (R)-(+)-goniothalamin 1, (R)-(+)-kavain 2 and (S)-(+)-7,8-dihydrokavain 3. Application of the Cosford protocol and direct conversion of aldehydes to β-keto-esters are the key steps in our approach.
A new procedure for the enantioselective vinylogous aldol reaction of Chan's diene
Villano, Rosaria,Acocella, Maria Rosaria,Massa, Antonio,Palombi, Laura,Scettri, Arrigo
, p. 3332 - 3334 (2007/10/03)
Chiral δ-hydroxy-β-ketoesters are easily available through the enantioselective vinylogous aldol reaction of Chan's diene promoted by a SiCl4/chiral phosphoramide catalytic system. The procedure is conveniently exploited for a very rapid approach to (+)-kavain, a natural bio-active α-pyrone compound.
