51116-72-4Relevant articles and documents
Remote Regioselective Radical C-H Functionalization of Unactivated C-H Bonds in Amides: The Synthesis of gem-Difluoroalkenes
Hu, Qu-Ping,Cheng, Jing,Wang, Ying,Shi, Jie,Wang, Bi-Qin,Hu, Ping,Zhao, Ke-Qing,Pan, Fei
supporting information, p. 4457 - 4462 (2021/05/26)
The site-selective functionalization of unactivated aliphatic amines is an attractive and challenging synthetic approach. We herein report a general strategy for the remote site-selective functionalization of unactivated C(sp3)-H bonds in amides by photogenerated amidyl radicals to form gem-difluoroalkenes with trifluoromethyl-substituted alkenes. The site selectivity is controlled by a 1,5-hydrogen atom transfer (HAT) process of the amide. This photocatalyzed transformation shows both chemo- and site-selectivity, facilitating the formation of a secondary, tertiary, or quaternary carbon center.
Design, synthesis, and evaluation of cystargolide-based β-lactones as potent proteasome inhibitors
Niroula, Doleshwar,Hallada, Liam P.,Le Chapelain, Camille,Ganegamage, Susantha K.,Dotson, Devon,Rogelj, Snezna,Groll, Michael,Tello-Aburto, Rodolfo
supporting information, p. 962 - 977 (2018/09/04)
The peptidic β-lactone proteasome inhibitors (PIs) cystargolides A and B were used to conduct structure-activity relationship (SAR) studies in order to assess their anticancer potential. A total of 24 different analogs were designed, synthesized and evaluated for proteasome inhibition, for cytotoxicity towards several cancer cell lines, and for their ability to enter intact cells. X-ray crystallographic analysis and subunit selectivity was used to determine the specific subunit binding associated with the structural modification of the β-lactone (P1), peptidic core, (Px and Py), and end-cap (Pz) of our scaffold. The cystargolide derivative 5k, structurally unique at both Py and P1, exhibited the most promising inhibitory activity for the β5 subunit of human proteasomes (IC50 = 3.1 nM) and significant cytotoxicity towards MCF-7 (IC50 = 416 nM), MDA-MB-231 (IC50 = 74 nM) and RPMI 8226 (IC50 = 41 nM) cancer cell lines. Cellular infiltration assays revealed that minor structural modifications have significant effects on the ability of our PIs to inhibit intracellular proteasomes, and we identified 5k as a promising candidate for continued therapeutic studies. Our novel drug lead 5k is a more potent proteasome inhibitor than carfilzomib with mid-to-low nanomolar IC50 measurements and it is cytotoxic against multiple cancer cell lines at levels approaching those of carfilzomib.
Primary, Secondary, and Tertiary γ-C(sp3)-H Vinylation of Amides via Organic Photoredox-Catalyzed Hydrogen Atom Transfer
Chen, Hui,Guo, Liangliang,Yu, Shouyun
supporting information, p. 6255 - 6259 (2018/10/05)
An efficient strategy for primary, secondary and tertiary aliphatic γ-C(sp3)-H vinylation of amides with alkenylboronic acids is reported. These reactions are catalyzed by visible-light organic photoredox agents. Regioselective γ-C(sp3)-H vinylation of amides is controlled by a 1,5-hydrogen atom transfer of an amidyl radical generated in situ.
Direct C-C Bond Formation from Alkanes Using Ni-Photoredox Catalysis
Ackerman, Laura K. G.,Martinez Alvarado, Jesus I.,Doyle, Abigail G.
, p. 14059 - 14063 (2018/10/24)
A method for direct cross coupling between unactivated C(sp3)-H bonds and chloroformates has been accomplished via nickel and photoredox catalysis. A diverse range of feedstock chemicals, such as (a)cyclic alkanes and toluenes, along with late-stage intermediates, undergo intermolecular C-C bond formation to afford esters under mild conditions using only 3 equiv of the C-H partner. Site selectivity is predictable according to bond strength and polarity trends that are consistent with the intermediacy of a chlorine radical as the hydrogen atom-abstracting species.
A detailed mechanistic investigation into the reaction of 3-methylpentanoic acid with Meldrum's acid utilizing online NMR spectroscopy
Dunn, Anna L.,Codina, Anna,Foley, David A.,Marquez, Brian L.,Zell, Mark T.
, p. 477 - 484 (2016/05/24)
A thorough investigation into the mechanism of the reaction of 3-methylpentanoic acid and Meldrum's acid using online NMR spectroscopy is reported. This study is an expansion of a previous analysis of this chemical transformation in the synthesis of an active pharmaceutical ingredient imagabalin. The 3-methylpentanoic acid analogue reveals similar behavior under the reaction conditions. Online NMR spectroscopy and offline characterization experiments reveal new information about the mechanism, providing conclusive spectroscopic evidence for the previously hypothesized dimer anhydride intermediate species 3-methylpentanoic anhydride as a productive intermediate. The presence of an acyl chloride intermediate species, 3-methylpentanoyl chloride, is also revealed for the first time in this synthesis.
ORGANIC COMPOUNDS
-
Paragraph 0050, (2015/04/28)
Branched optionally unsaturated ketones particularly useful in providing typical and characteristic orris facets to perfume compositions.
ORGANIC COMPOUNDS
-
Page/Page column 12, (2013/12/03)
Branched optionally unsaturated ketones particularly useful in providing typical and characteristic orris facets to perfume compositions,
Steric effects and mechanism in the formation of hemi-acetals from aliphatic aldehydes
Daw, Graham,Regan, Andrew C.,Watt, C. Ian F.,Wood, Evan
, p. 1048 - 1057 (2014/01/06)
Some physical properties (pKa, log POW, boiling points) of hexanoic acid 1 (X = COOH) and its seven isomers 2, 3, 4, 5, 6, 7, 8 (X = COOH) are reported. Hexanal 1 (X = CHO) and its seven isomeric aldehydes 2, 3, 4, 5, 6, 7, 8 (X = CHO) are shown to equilibrate, in methanol solution, with their hemi-acetals. Logarithms of equilibrium constants correlate with values of Es for the isomeric C5H11 substituents, and with logs of relative rates for saponification of the corresponding methyl esters with ρ = 0.52, reflecting the reduced steric demand of hydrogen compared to oxygen in the quaternization of ester and aldehydic carbonyl groups. Rates of equilibration have also been measured in buffered methanol. For hexanal, with a 2:1 Et3N:AcOH buffer, the buffer-independent contribution is dominated by the methoxide catalysed pathway. Rates in this medium have been determined for isomers 1, 2, 3, 4, 5, 6, 7, 8 (X = CHO), and their logarithms do not correlate with logarithms of equilibrium constants for hemi-acetal formation or with substituent steric parameters derived from ester formation or saponification, indicating that the steric changes associated with full quaternization of the carbonyl group are not mirrored in the transition structures for hemi-acetal formation. It is suggested that transition states for hemi-acetal formation are relatively early so that steric interactions are effectively those between the nucleophile and ground state conformations of the aldehydes. A comparison of the entropies of hemi-acetal formation with entropies of activation has provided a basis for a suggested transition structure. Comparisons with acid chloride hydrolyses are made. Copyright 2013 John Wiley & Sons, Ltd. Logarithms of equilibrium constants for formation hemi-acetals of hexanal and its seven isomeric aldehydes correlate well with values of Es for the isomeric C5H11 substituents, and with logs of relative rates for saponification of the corresponding methyl esters. Logarithms of rate constants for hemi-acetal formation do not, indicating that the steric changes associated with full quaternization of the carbonyl group are not mirrored in the transition structures for hemi-acetal formation. The reasons for this are discussed. Copyright
Syntheses and evaluation of anticonvulsant profile and teratogenicity of novel amide derivatives of branched aliphatic carboxylic acids with 4-aminobenzensulfonamide
Hen, Naama,Bialer, Meir,Wlodarczyk, Bogdan,Finnell, Richard H.,Yagen, Boris
scheme or table, p. 4177 - 4186 (2010/09/04)
Despite the availability of 14 new antiepileptic drugs (AEDs), about 30% of epileptic patients are not seizure-free. Consequently there is substantial need to develop new effective AEDs. A novel class of aromatic amides composed of phenylacetic acid or branched aliphatic carboxylic acids, with five to nine carbons in their carboxylic moiety, and aminobenzenesulfonamide were synthesized and evaluated in the anticonvulsant rat-maximal electroshock (MES) and subcutaneous metrazol seizure (scMet) tests. Fourteen of the synthesized amides had an anticonvulsant ED50 of 50 values of 7.6, 9.9, and 9.4 mg/kg and remarkable protective index (PI = TD 50/ED50) values of 65.7, 50.5, and 53.2, respectively. These potent sulfanylamides caused neural tube defects only at doses markedly exceeding their effective dose. The anticonvulsant properties of these compounds make them potential candidates for further development as new, potent, and safe AEDs.
Antinociceptive effect of extracts and compounds from Hofmeisteria schaffneri
Angeles-Lopez, Guadalupe,Perez-Vasquez, Araceli,Hernandez-Luis, Francisco,Deciga-Campos, Myrna,Bye, Robert,Linares, Edelmira,Mata, Rachel
experimental part, p. 425 - 432 (2011/11/14)
Ethnopharmacological relevance: Hofmeisteria schaffneri (Asteraceae) is a medicinal plant widely commercialized in the most important Markets of Mexico City for the treatment of gastro-intestinal complaints and skin afflictions. Aim of the study: The main goals of this study were to establish the potential acute toxicity and the antinociceptive activity in animal models of several preparations and compounds from Hofmeisteria schaffneri. Materials and methods: The aqueous and organic extracts as well as the essential oil of Hofmeisteria schaffneri were prepared by infusion, maceration and hydrodistillation, respectively. Investigation of the acute toxicity was accomplished by the Lorke method. The antinociceptive effect was assessed using the writhing and the hot plate tests. Natural compounds were isolated by standard phytochemical procedures. In addition, a few thymol esters were prepared by chemical synthesis. The stability of natural and synthetic esters was qualitatively analyzed by measuring their susceptibility to hydrolysis by pig liver estearase and mouse plasma at 37°C. Results: The LD50 for each preparation tested was higher than 5000mg/kg revealing that they were not toxic to mice after exposure for short space of time. On the other hand, the extracts showed significant antinociceptive effect when tested in the hot plate model. The most active natural product as antinociceptive agent was hofmeisterin III (1) which also was the most stable in the stability study. Its pharmacological effect seems to be partially mediated by an opioid mechanism since naloxone inhibits its action. Using compound 1 as a lead molecule, several synthetic thymol esters were prepared and only compounds 13, 15 and 17 were antinoceptive at the dose of 1mg/kg. Conclusions: The present investigation provided evidence of the efficacy of several preparations of Hofmeisteria schaffneri as antinociceptive agents. The most active preparation was the essential oil which contained large amount of hofmeisterin III (1) and other thymol derivatives. Some novel synthetic analogs of hofmeisterin III with antinociceptive properties were discovered. The nature of the ester chain of these analogs did not have a clear impact on the antinociceptive activity. The phyto-preparations analyzed in this study were not toxic to mice according to the Lorke's test; therefore considering their long term use of the plant they might be secure for human consumption.