- Stereoselective synthesis of 1-methyl-1,2-and 1,3-cyclopentanediols via γ-lactones
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A method for the synthesis of 1-methylcarbapentofuranose derivatives was developed, where 1,2-cis- and 1,2-trans-4-hydroxymethyl-1- methylcyclopentanediols were obtained from intramolecular opening of a 4-epoxy-4-methyl-γ-lactone. An intramolecular aldol reaction of 4-methyl-4-(2-oxoethyl)-γ-lactone derivatives yielded 1,3-cis- and 1,3-trans-4-hydroxymethyl-1-methylcyclopentanediols.
- Niidu,Paju,Mueuerisepp,Jaerving,Kailas,Pehk,Lopp
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- OXIDATION OF TETRAHYDROFURAN METHANOL DERIVATIVES WITH PYRIDINIUM CHLOROCHROMATE: A FACILE SYNTHESIS OF γ-BUTYROLACTONES
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Treatment of a number of tetrahydrofuran methanol derivatives with pyridinium chlorochromate led to the formation of the corresponding γ-butyrolactones with the loss of one or more carbon atoms in good yields under mild reaction conditions.
- Baskaran, S.,Chandrasekaran, S.
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- Palladium-Catalyzed Cyclization of Free Hydroxyalkenoic Acids: Regio- and Chemoselective Access to Methylene Lactones
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A general and collective synthesis of medium-sized methylene lactones via controlled cyclizations of easily accessible collective precursors is described. The rapid composition of key–hydroxyalkenoic acid scaffold yields an assembly of oxocanones, oxepanones, and pyranones in a regioselective and stereodirected fashion via palladium-catalyzed cyclization. (Figure presented.).
- Mostinski, Yelena,Kotikalapudi, Ramesh,Valerio, Viviana,Nataf, Riva,Tsvelikhovsky, Dmitry
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- Catalytic Redox Chain Ring Opening of Lactones with Quinones to Synthesize Quinone-Containing Carboxylic Acids
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Catalytic ring opening of five- to eight-membered lactones with quinones is achieved through a redox chain mechanism. With low loading of a simple metal triflate Lewis acid catalyst and a chain initiator, C-H bonds of many quinones were efficiently functionalized with carboxylic acid-containing side chains. This method also features 100% atom economy and wide substrate scope. A novel route to the anti-asthma drug Seratrodast was developed. Mechanism study suggests that the redox chain reaction likely undergoes a carbocation intermediate.
- Xu, Xiao-Long,Li, Zhi
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supporting information
p. 5078 - 5081
(2019/09/03)
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- CYCLIZATION PROCESSES OF HYDROXYALKENOIC AICDS AND PRODUCTS THEREOF
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The invention provides efficient cyclization processes of hydroxyalkenoic acids and products produced therefrom. The following reactions are claimed: Formula (I), (II), (V) and (VI).
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Page/Page column 32; 38-39
(2018/09/12)
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- The scent of bacteria: Headspace analysis for the discovery of natural products
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Volatile compounds released by 50 bacterial strains, 45 of them actinobacteria in addition to three chloroflexi and two myxobacteria, have been collected by use of a closed-loop stripping apparatus, and the obtained headspace extracts have been analyzed by GC-MS. Excluding terpenes that have recently been published elsewhere, 254 compounds from all kinds of compound classes have been identified. For unambiguous compound identification several reference compounds have been synthesized. Among the detected volatiles 12 new natural products have been found, in addition to mellein, which was released by Saccharopolyspora erythraea. The iterative PKS for this compound has recently been identified by in vitro experiments, but mellein production in S. erythraea has never been reported before. These examples demonstrate that headspace analysis is an important tool for the discovery of natural products that may be overlooked using conventional techniques. The method is also useful for feeding experiments with isotopically labeled precursors and was applied to investigate the biosynthesis of the unusual nitrogen compound 1-nitro-2-methylpropane, which arises from valine. Furthermore, several streptomycetes emitted compounds that were previously recognized as insect pheromones, thus questioning if bacterial symbionts are involved in insect communication.
- Citron, Christian A.,Rabe, Patrick,Dickschat, Jeroen S.
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supporting information
p. 1765 - 1776
(2013/01/15)
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- Diastereoselective γ-vinyl butyrolactone synthesis via gold catalyzed cyclization of allylic acetate
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An efficient method for the preparation of polysubstituted γ-vinyl butyrolactones was developed through gold catalyzed highly diastereoselective cyclization of the malonate substituted allylic acetates.
- Wang, Ya-Hui,Zhu, Li-Li,Zhang, Yu-Xin,Chen, Zili
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supporting information; experimental part
p. 577 - 579
(2010/05/01)
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- Vitamin E metabolites: Synthesis of [D2]- and [D 3]-γ-CEHC
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Deuterated analogues of α- and γ-CEHC, main urinary and plasma metabolites of vitamin E, can be traced and accurately determined quantitatively by MS in complex matrices. In that regard, here we report the first synthesis of rac-[D3]-γ-CEHC together with a simple route to 7a,8a-[D2]-γ-CEHC through the set up of efficient procedures for the preparation of the corresponding deuterated hydroquinone building blocks. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Mazzini, Francesco,Galli, Francesco,Salvadori, Piero
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p. 5588 - 5593
(2008/02/04)
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- Compounds having protected hydroxy groups
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The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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- Compounds having protected hydroxy groups
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The present invention relates to compounds with protected hydroxy groups of formula (I) These compounds are precursors for organoleptic agents, such as fragrances, and masking agents and for antimicrobial agents. When activated, the compounds of formula (I) are cleaved and form one or more organoleptic and/or antimicrobial compounds.
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- Precursor compounds
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The compounds of the formula I are precursors for organoleptic and antimicrobial compounds. The latter are generated in the presence of skin bacteria, enzymes or acidic or alkaline conditions. One precursor molecule can provide one or more different compounds.
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- Beta-ketoester compounds
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The beta-ketoesters of formula I are useful as precursors for organoleptic compounds, especially for flavors, fragrances and masking agents and antimicrobial compounds.
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- A General Approach to the Synthesis of Butanolides: Synthesis of the Sex Pheromone of the Japanese Beetle
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A variety of substituted γ-hydroxy olefins 1 have been converted to butanolides 4 in very high yield in a three-step sequence involving bromoetherification, elimination, and oxidative cleavage.The key step in the overall transformation is the highly selective oxidative cleavage of enol ethers 3 with PCC under very mild reaction conditions.Application of this methodology has been exemplified in the synthesis of the Japanese beetle pheromone.
- Baskaran, Sundarababu,Islam, Imadul,Chandrasekaran, Srinivasan
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p. 891 - 895
(2007/10/02)
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- Pyridinium Chlorochromate in Organic Synthesis. A Facile and Selective Oxidative Cleavage of Enol Ethers
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Pyridinium chlorochromate (PCC) has been found to be selective reagent for the oxidative cleavage of enol ethers to esters or keto lactones in high yields.
- Baskaran, S.,Islam, I.,Raghavan, Malini,Chandrasekaran, S.
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p. 1175 - 1178
(2007/10/02)
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