- Asymmetric total synthesis of dihydroisocoumarins: 6-methoxymellein, kigelin and fusarentin 6, 7 dimethyl ether by employing proline catalysed asymmetric α-aminoxylation
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A concise asymmetric total synthesis of dihydroisocoumarins such as 6-methoxymellein, kigelin and fusarentin 6,7-dimethyl ether in high enantiopurity have been achieved from non-chiral aldehydes by employing proline catalysed asymmetric α-aminoxylation reaction. The required stereochemistry of hydroxyl group have been generated by alternating L or D proline as a organocatalyst in α-aminoxylation step and lactone ring is assembled by oxa-Pictet-Spengler cyclisation reaction as the key steps.
- Mane, Baliram B.,Markad, Sachin B.,Waghmode, Suresh B.
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- Modular synthesis and biological investigation of 5-hydroxymethyl dibenzyl butyrolactones and related lignans
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Dibenzyl butyrolactone lignans are well known for their excellent biological properties, particularly for their notable anti-proliferative activities. Herein we report a novel, efficient, convergent synthesis of dibenzyl butyrolactone lignans utilizing the acyl-Claisen rearrangement to stereoselectively prepare a key intermediate. The reported synthetic route enables the modification of these lignans to give rise to 5-hydroxymethyl derivatives of these lignans. The biological activities of these analogues were assessed, with derivatives showing an excellent cytotoxic profile which resulted in programmed cell death of Jurkat T-leukemia cells with less than 2% of the incubated cells entering a necrotic cell death pathway.
- Davidson, Samuel J.,Pilkington, Lisa I.,Dempsey-Hibbert, Nina C.,El-Mohtadi, Mohamed,Tang, Shiying,Wainwright, Thomas,Whitehead, Kathryn A.,Barker, David
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- Highly trans-Selective Arylation of Achmatowicz Rearrangement Products by Reductive γ-Deoxygenation and Heck-Matsuda Reaction: Asymmetric Total Synthesis of (-)-Musellarins A-C and Their Analogues
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Fully functionalized pyranuloses derived from Achmatowicz rearrangement (AR) are versatile building blocks in organic synthesis. However, access to trans-2,6-dihydropyrans from pyranuloses remains underexplored. Herein, we report a new two-step trans arylation of AR products to access 2,6-trans-dihydropyranones. This new trans-arylation method built on numerous plausible, but unsuccessful, direct arylation reactions, including Ferrier-type and Tsuji-Trost-type reactions, was finally enabled by an unprecedented, highly regioselective γ-deoxygenation of AR products by using Zn/HOAc and a diastereoselective Heck-Matsuda coupling. The synthetic utility of the reaction was demonstrated in the first asymmetric total synthesis of (-)-musellarins A-C and 12 analogues in 11-12 steps. The brevity and efficiency of our synthetic route permitted preparation of enantiomerically pure musellarins and analogues (>20 mg) for preliminary cytotoxicity evaluation, which led us to identify two analogues with three-to-six times greater potency than the musellarins as promising new leads. O leaves, Ar comes: A highly regio- and diastereoselective trans-arylation of Achmatowicz rearrangement products by an unprecedented Zn-mediated reductive γ-deoxygenation and Heck-Matsuda reaction was developed for the efficient synthesis of trans-2-aryl-6-alkyl dihydropyranones (see scheme: L.A.=Lewis acid). The synthetic utility of this new method was further demonstrated in the first asymmetric total synthesis of (-)-musellarins A-C and 12 analogues in 11-12 steps.
- Li, Zhilong,Ip, Fanny C. F.,Ip, Nancy Y.,Tong, Rongbiao
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supporting information
p. 11152 - 11157
(2015/11/10)
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- COMPOUNDS FOR TREATMENT OF ANGIOGENESIS-MEDIATED DISEASES
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Synthetic cremastranone and cremastranone analogs are disclosed. Additionally, methods for synthesizing cremastranone and cremastranone analogs are disclosed. Methods of treating ocular neovascularization disorders and treating angiogenesis-mediated disease are also disclosed.
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- Synthesis of salidroside analogues and their ability of DPPH radical scavenging activity
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Salidroside is a phenylpropanoid glycoside isolated from Rhodiolarosea L., a traditional Chinese medicinal plant, and has displayed a broad spectrum of pharmacological properties. In this paper, about 22 novel glycosides have been synthesized and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenge activity of each glycoside has been evaluated. 2-(3,4,5-Trihydroxyphenyl)ethyl β-D-galactopyranoside and 3-(3,4,5-trihydroxyphenyl)propyl β-D-glucopyranoside exhibit significant activity prior to salidroside and Vitamin C with EC50 values of 35.85 μM and 36.71 μM, respectively. The results indicate that the phenolic hydroxyl group of these compounds is important for radical scavenging activity and phenyl ring substitution by electron-donating substituents lead to increased antioxidant activity.
- Zheng, Cheng,Guo, Yibing,Meng, Ying,Dou, Sufeng,Shao, Jian,Yang, Yumin
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p. 654 - 664
(2013/07/11)
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- Process for the preparation of carboxylic acids and derivatives of them
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The subject matter of the invention is a process for the preparation of carboxylic acids and derivatives of them of the general formula wherein Rmeans hydrogen, or a C1 4alkyl or a (C1 5alkoxy)carbonyl group, R1is as defined in claim 1, R7stands for hydrogen or a C1 7alkyl group and R8means hydrogen or a carboxyl group, by reacting a 1,3-dioxane-4,6-dione derivative of the general formula wherein R9stands for a C1 4alkyl group or a phenyl group, optionally monosubstituted by halogen and R10stands for hydrogen or a C1 5alkyl group or R9 and R10together form a pentamethylene group, and an aldehyde or ketone of the general formula in the presence of formic acid and of [a] amine(s) and, if desired, of an alcohol of the general formula, , R7 - OH VI,, , wherein R7is a C1 7alkyl group, at a temperature of 20 to 140°C, and/or, reducing an unsaturated 1,3-dioxane-4,6-dione derivative of the general formula and/or, a 1,3-dioxane-4,6-dione derivative of the general formula with formic acid in the presence of [a] amine(s) and, if desired, of an alcohol as above defined.
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- Process for the preparation of carboxylic acids and derivatives of them
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The subject matter of the invention is a process for the preparation of carboxylic acids and derivatives of them of the general formula STR1 wherein R means hydrogen, or a C1-4 alkyl or a (C1-5 alkoxy)carbonyl group, R1 is as defined in claim 1, R7 stands for hydrogen or a C1-7 alkyl group and R8 means hydrogen or a carboxyl group, by reacting a 1,3-dioxane-4,6-dione derivative of the general formula STR2 wherein R9 stands for a C1-4 alkyl group or a phenyl group, optionally monosubstituted by halogen and R10 stands for hydrogen or a C1-5 alkyl group or R9 and R10 together form a pentamethylene group, and an aldehyde or ketone of the general formula STR3 in the presence of formic acid.
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