19498-72-7Relevant articles and documents
CLAISEN REARRANGEMENT OF THE LITHIUM ENOLATE OF 1-(2-THIENYL)ALKYL ALKANOATE AND THE BIRCH REDUCTION OF THE RESULTING 2-(3-THIENYL)ALKANOIC ACID.
Sado,Abe,Inuzuka,Shirai,Kumamoto
, p. 1665 - 1668 (1983)
It was found that the Claisen rearrangement of the lithium enolate of 1-(2-thienyl)alkyl alkanoate in refluxing THF resulted in the formation of 2-(3-thienyl)alkanoic acid (2). Similarly, when the lithium enolate of 4-(2-thienyl)-4-butanolide was stirred at room temperature in the presence of hexamethylphosphoric triamide, 5,6-dihydro-4H-cyclopenta left bracket b right bracket thiophene-4-carboxylic acid was obtained. Further, it was found that the Birch reduction of 2 and subsequent alkylation with benzyl bromide gave a regioselective ring-opening product, 4-benzylthio-3-ethyl-3-alkanoic acid, in a good yield. The Birch reduction of 2-thienylacetic acid, followed by alkylation with benzyl bromide, also gave (Z)-3-benzylthio-3-hexenoic acid as the main product.
Iridium Complex-Catalyzed C2-Extension of Primary Alcohols with Ethanol via a Hydrogen Autotransfer Reaction
Kobayashi, Masaki,Itoh, Satoshi,Yoshimura, Keisuke,Tsukamoto, Yuya,Obora, Yasushi
, p. 11952 - 11958 (2020/10/23)
The development of a C2-extension of primary alcohols with ethanol as the C2 source and catalysis by [Cp*IrCl2]2 (where Cp? = pentamethylcyclopentadiene) is described. This new extension system was used for a range of benzylic alcohol substrates and for aliphatic alcohols with ethanol as an alkyl reagent to generate the corresponding C2-extended linear alcohols. Mechanistic studies of the reaction by means of intermediates and deuterium labeling experiments suggest the reaction is based on hydrogen autotransfer.
Biocatalytic reduction of α,β-unsaturated carboxylic acids to allylic alcohols
Aleku, Godwin A.,Leys, David,Roberts, George W.
, p. 3927 - 3939 (2020/07/09)
We have developed robust in vivo and in vitro biocatalytic systems that enable reduction of α,β-unsaturated carboxylic acids to allylic alcohols and their saturated analogues. These compounds are prevalent scaffolds in many industrial chemicals and pharmaceuticals. A substrate profiling study of a carboxylic acid reductase (CAR) investigating unexplored substrate space, such as benzo-fused (hetero)aromatic carboxylic acids and α,β-unsaturated carboxylic acids, revealed broad substrate tolerance and provided information on the reactivity patterns of these substrates. E. coli cells expressing a heterologous CAR were employed as a multi-step hydrogenation catalyst to convert a variety of α,β-unsaturated carboxylic acids to the corresponding saturated primary alcohols, affording up to >99percent conversion. This was supported by the broad substrate scope of E. coli endogenous alcohol dehydrogenase (ADH), as well as the unexpected CC bond reducing activity of E. coli cells. In addition, a broad range of benzofused (hetero)aromatic carboxylic acids were converted to the corresponding primary alcohols by the recombinant E. coli cells. An alternative one-pot in vitro two-enzyme system, consisting of CAR and glucose dehydrogenase (GDH), demonstrates promiscuous carbonyl reductase activity of GDH towards a wide range of unsaturated aldehydes. Hence, coupling CAR with a GDH-driven NADP(H) recycling system provides access to a variety of (hetero)aromatic primary alcohols and allylic alcohols from the parent carboxylates, in up to >99percent conversion. To demonstrate the applicability of these systems in preparative synthesis, we performed 100 mg scale biotransformations for the preparation of indole-3-aldehyde and 3-(naphthalen-1-yl)propan-1-ol using the whole-cell system, and cinnamyl alcohol using the in vitro system, affording up to 85percent isolated yield.
Remote Functionalization of α,β-Unsaturated Carbonyls by Multimetallic Sequential Catalysis
Romano, Ciro,Fiorito, Daniele,Mazet, Clément
supporting information, p. 16983 - 16990 (2019/10/28)
The remote functionalization of α,β-unsaturated carbonyls by an array of multimetallic sequential catalytic systems is described. The reactions are triggered by hydrometalation using [Pd-H] or [Ru-H] isomerization catalysts and driven by the formation of thermodynamically more stable 1,2-vinyl arenes. The Pd-catalyzed deconjugative isomerization was combined with a Cu-catalyzed β-borylation of the transiently generated styrenyl derivatives to deliver a range of products that would not be accessible with the use of a single catalyst. [Pd/Cu] catalytic systems were also identified for the highly enantioselective α-hydroboration and α-hydroamination of the styrenyl intermediates. Difunctionalization simultaneously at the benzylic and homobenzylic positions was achieved by combining the isomerization process with Sharpless asymmetric dihydroxylation (SAD) using [Pd/Os] or [Ru/Os] couples. Starting from a simple α,β-unsaturated ester, an isomerization/dihydroxylation/lactonization sequence gave access to a naturally occurring γ-butyrolactone in good yield, with excellent diastereo- and enantioselectivity.
Structure-Odor Correlations in Homologous Series of Mercapto Furans and Mercapto Thiophenes Synthesized by Changing the Structural Motifs of the Key Coffee Odorant Furan-2-ylmethanethiol
Schoenauer, Sebastian,Schieberle, Peter
, p. 4189 - 4199 (2018/05/01)
Furan-2-ylmethanethiol (2-furfurylthiol; 2-FFT, 1) is long-known as a key odorant in roast and ground coffee and was also previously identified in a wide range of thermally treated foods such as meat, bread, and roasted sesame seeds. Its unique coffee-like odor quality elicited at very low concentrations, and the fact that only a very few compounds showing a similar structure have previously been described in foods make 1 a suitable candidate for structure-odor activity studies. To gain insight into the structural features needed to evoke a coffee-like odor at low concentrations, 46 heterocyclic mercaptans and thio ethers were synthesized, 32 of them for the first time, and their odor qualities and odor thresholds were determined. A movement of the mercapto group to the 3-position kept the coffee-like aroma but led to an increase in odor threshold. A separation of the thiol group from the furan ring by an elongation of the carbon side chain caused a loss of the coffee-like odor and also led to an increase in odor thresholds, especially for ω-(furan-2-yl)alkane-1-thiols with six or seven carbon atoms in the side chain. A displacement of the furan ring by a thiophene ring had no significant influence on the odor properties of most of the compounds studied, but the newly synthesized longer-chain 1-(furan-2-yl)- and 1-(thiophene-2-yl)alkane-1-thiols elicited interesting passion fruit-like scents. In total, only 4 out of the 46 compounds also showed a coffee-like odor quality like 1, but none showed a lower odor threshold. Besides the odor attributes, also retention indices, mass spectra, and NMR data of the synthesized compounds were elaborated, which are helpful in possible future identification of these compounds in trace levels in foods or other materials.
Synthesis and bioactivities of novel piperazine-containing 1,5-Diphenyl-2-penten-1-one analogues from natural product lead
Xu, Gaofei,Yang, Xinling,Jiang, Biaobiao,Lei, Peng,Liu, Xili,Wang, Qingmin,Zhang, Xuebo,Ling, Yun
supporting information, p. 1849 - 1853 (2016/07/27)
A series of novel 1,5-Diphenyl-2-penten-1-one analogues (7a–h, 8a–h) with piperazine moiety have been designed and synthesized on the basis of natural product 1,5-Diphenyl-2-penten-1-one (I). All the synthesized compounds were evaluated in vitro for anti-plant pathogenic fungi activities and insecticidal activities. The results indicated that most of these analogues exhibited moderate antifungal activities and moderate to good insecticidal activities. Amongst them, the most potent 7c, 7e and 7h keep a mortality of 100% against larva of mosquito at the concentration of 1?mg/L. Initial structure–activity relationship (SAR) analysis showed that, a methyl group can influence the biological activities of these compounds significantly, the compounds with N′-unsubstituted piperazine showed much better antifungal activities and larvicidal activity against mosquito than the compounds with N′-methylated piperazine. In addition, the larvicidal activity against mosquito had sharply decline when the substituent on benzene ring was changed from 4-position to 2 or 3-position.
Synthesis and fungicidal activity study of novel daphneolone analogs with 2,6-dimethylmorpholine
Xu, Gao-Fei,Yang, Xin-Ling,Lei, Peng,Liu, Xi-Li,Zhang, Xue-Bo,Ling, Yun
supporting information, p. 555 - 558 (2016/04/26)
A series of novel daphneolone analogs was designed and synthesized on the basis of natural product 1,5-diphenyl-2-penten-1-one (I) from Stellera chamaejasme L. as lead compound, whereby 2,6-dimethylmorpholine moiety was introduced to replace 1-phenyl group. Their structures were confirmed by IR, 1H NMR, and HRMS (ESI) or elemental analysis, 13C NMR for some representative compounds. The two isomers of target compounds were separated and identified by NOESY technique and chemical method. All of the synthesized compounds have been evaluated for anti-plant pathogenic fungi activities. The results showed that some compounds exhibited moderate to good antifungal activities against tested fungi at the concentration of 50 mg/L. Among them, compound 7d, with a 4-bromine-substituted phenyl group and cis-2,6-dimethylmorpholine moiety, displayed best activity with an EC50 of 23.87 μmol/L against Valsa Mali, superior to lead compound I. In addition, preliminary structure-activity relationship analysis indicated that, between two isomers of target compounds, the antifungal activities of the isomer with cis-2,6-dimethylmorpholine were better than the trans-isomer.
Synthesis of enantioenriched alkylfluorides by the fluorination of boronate complexes
Sandford, Christopher,Rasappan, Ramesh,Aggarwal, Varinder K.
supporting information, p. 10100 - 10103 (2015/09/01)
The enantiospecific conversion of chiral secondary boronic esters into alkylfluorides is reported. Boronate complexes derived from boronic esters and PhLi were used as nucleophiles, with Selectfluor II as the electrophilic fluorinating agent, to afford alkylfluorides in short reaction times. The addition of styrene as a radical trap was found to enhance enantiospecificity. A broad range of alkyl boronic esters were converted into alkylfluorides with almost complete enantiospecificity by this method.
NOVEL HETEROCYCLIC ACRYLAMIDES AND THEIR USE AS PHARMACEUTICALS
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Page/Page column 87-88, (2011/06/19)
The invention relates to novel heterocyclic acrylamide compounds (I), to the preparation of the compounds and intermediates used therein, to the use of the compounds as antibacterial medicaments and pharmaceutical compositions containing the compounds.
NOVEL COMPOUNDS AS CANNABINOID RECEPTOR LIGANDS
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Page/Page column 87-88, (2010/06/11)
The present application relates to isothiazolylidene containing compounds of Formula (I) wherein R1, R2, R3, R4, and L are as defined in the specification, compositions comprising such compounds, and methods for treating conditions and disorders using such compounds and compositions.
