4031-15-6Relevant academic research and scientific papers
Oxidative Cleavage of Indoles Mediated by Urea Hydrogen Peroxide or H2O2 in Polar Solvents
Llopis, Natalia,Gisbert, Patricia,Baeza, Alejandro
supporting information, p. 3245 - 3249 (2021/06/08)
The oxidative cleavage of indoles (Witkop oxidation) involving the use of H2O2 or urea hydrogen peroxide in combination with a polar solvent has been described. Among these solvents, 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) stands out as the one affording the corresponding 2-ketoacetanilides generally in higher yields The protocol described has also enabled the oxidation of different pyrroles and furans derivatives. Furthermore, the procedure was implemented in a larger-scale and HFIP was distilled from the reaction mixture and reused (up to 4 cycles) without a significant detriment in the reaction outcome, which remarks its sustainability and applicability. (Figure presented.).
Mechanistic Insights into Iron-Catalyzed C-H Bond Activation and C-C Coupling
Brewer, Samantha M.,Schwartz, Timothy M.,Mekhail, Magy A.,Turan, Lara S.,Prior, Timothy J.,Hubin, Timothy J.,Janesko, Benjamin G.,Green, Kayla N.
, p. 2467 - 2477 (2021/08/03)
Iron-catalyzed C-C coupling reactions of pyrrole provide a unique alternative to the traditional Pd-catalyzed counterpart. However, many details regarding the actual mechanism remain unknown. A series of macrocyclic iron(III) complexes were used to evaluate specifics related to the role of O2, radicals, and μ-oxodiiron-complex participation in the catalytic cycle. It was determined that the mononuclear tetra-Azamacrocyclic complex is a true catalyst and not a stoichiometric reagent, while more than one equivalent of a sacrificial oxidant is needed. Furthermore, the reaction does not proceed through an organic radical pathway. μ-Oxodiiron complexes are not involved in the main catalytic pathway, and the dimers are, in fact, off-cycle species that decrease catalytic efficiency.
Direct Catalytic Desaturation of Lactams Enabled by Soft Enolization
Chen, Ming,Dong, Guangbin
supporting information, p. 7757 - 7760 (2017/06/21)
A direct catalytic method is described for the α,β-desaturation of N-protected lactams to their conjugated unsaturated counterparts under mildly acidic conditions. The reaction is consistently operated at room temperature and tolerates a wide range of functional groups, showing reactivity complementary to that of prior desaturation methods. Lactams with various ring sizes and substituents at different positions all reacted smoothly. The synthetic utility of this method is demonstrated in a concise synthesis of Rolipram. In addition, linear amides also prove to be competent substrates, and the phthaloyl-protected product serves as a convenient precursor to access various conjugated carboxylic acid derivatives. Strong bases are avoided in this desaturation approach, and the key is to merge soft enolization with a Pd-catalyzed oxidation process.
Pipelongumine and its derivatives and producing method thereof
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Page/Page column 14, (2017/01/05)
The present invention relates to piperlongumine, a derivative thereof, and a synthesizing method thereof. The piperlongumine and the derivatives thereof are synthesized by making a variety of amides/lactams react with a variety of acid chlorides of 3,4,5-trimethoxycinnamic acid. In addition, anti-inflammatory effect is tested in RAW264.7 macrophage induced by LPS with respect to the compounds. The piperlongumine of the compounds shows maximum inhibition activity (91.3%) and has cytotoxicity. A compound 3 having alpha, beta-unsaturated butyrolactam does not show cytotoxicity, and has a significant inhibition effect of 64.8%. An amide/lactam region connected to an alpha, beta-unsaturated cinnamoyl group having the chain length of at least three carbons exhibits a strong anti-inflammatory activity without cytotoxicity.
A facile approach to α,β-unsaturated lactams by ring-closing metathesis
Gondal, Humaira Yasmeen,Buisson, Didier
, p. 183 - 191 (2016/07/28)
[MediaObject not available: see fulltext.]A facile and efficient strategy for the synthesis of α,β-unsaturated lactams through ring-closing metathesis of easily prepared diene amides is being reported here. Reaction conditions were optimized for metathetic cyclization of diene amides to obtain five- to sevenmembered unsubstituted and β-substituted α,β-unsaturated lactams in good to excellent yield.
Synthesis and biological evaluation of piperlongumine derivatives as potent anti-inflammatory agents
Seo, Young Hwa,Kim, Jin-Kyung,Jun, Jong-Gab
supporting information, p. 5727 - 5730 (2015/01/08)
Piperlongumine (PL) and its derivatives were synthesized by the direct reaction between acid chloride of 3,4,5-trimethoxycinnamic acid and various amides/lactams. Later their anti-inflammatory effects were evaluated in lipopolysaccharide (LPS)-induced RAW-264.7 macrophages. Of the piperlogs prepared in this study, the maximum (91%) inhibitory activity was observed with PL (IC50 = 3 μM) but showed cytotoxicity whereas compound 3 (IC50 = 6 μM) which possess α,β-unsaturated γ-butyrolactam moiety offered good level (65%) of activity with no cytotoxicity. This study revealed that amide/lactam moiety connected to cinnamoyl group with minimum 3 carbon chain length and α,β-unsaturation is fruitful to show potent anti-inflammatory activity.
Synthetic strategies for the synthesis and transformation of substituted pyrrolinones as advanced intermediates for rhazinilam analogues
Kholod, Inga,Vallat, Olivier,Buciumas, Ana-Maria,Neels, Antonia,Neier, Reinhard
supporting information, p. 7865 - 7877 (2015/03/04)
The biaryl core structure of rhazinilam with its fixed dihedral angle is a pivotal element for its unique in vitro cytotoxic activity. Most of the related natural products are oxidized versions of rhazinilam. Replacing the sensitive pyrrole ring by a pyrrolinone ring is the basis of our initial strategy towards rhazinilam analogues. With this goal, variants of the sequence crossed Mukaiyama aldol reaction followed by the Staudinger reaction were studied. Reacting a suitably substituted acetophenone with O-methyl O-trimethylsilyl ketene acetal gave pyrrolinones 8a and 8b in good to excellent yields. These intermediates could be transformed in four high-yielding steps into the pyrrolic precursors 7a-c containing all the atoms necessary for the construction of rings A, B, and C of rhazinilam. Our studies illustrate a lack of stability of these intermediates. Alternative synthetic approaches towards this central biaryl core structure are described.
Organocatalytic asymmetric direct vinylogous Michael addition of α,β-unsaturated γ-butyrolactam to nitroolefins
Choudhury, Abhijnan Ray,Mukherjee, Santanu
supporting information; experimental part, p. 7313 - 7320 (2012/10/07)
The first organocatalytic enantioselective direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactam to nitroolefins is developed using cinchona alkaloids as the catalysts. Both product enantiomers are accessible with moderate to good enantioselectivity.
Catalytic, asymmetric vinylogous Mukaiyama aldol reactions of pyrrole- and furan-based dienoxy silanes: How the diene heteroatom impacts stereocontrol
Curti, Claudio,Ranieri, Beatrice,Battistini, Lucia,Rassu, Gloria,Zambrano, Vincenzo,Pelosi, Giorgio,Casiraghi, Giovanni,Zanardi, Franca
supporting information; experimental part, p. 2011 - 2022 (2010/11/17)
Denmark's chiral bisphosphoramide/silicon tetrachloride system performs as an excellent Lewis base-Lewis acid catalyst for the vinylogous Mukaiyama aldol reaction of pyrrole- and furan-based dienoxy silanes with aromatic and heteroaromatic aldehydes. This asymmetric methodology provides a powerful synthetic entry to a variety of d-hydroxylated g-butenolide-type frameworks with high efficiency and valuable margins of regio-, diastereo-, and enantioselectivity. Notably, the nature of the heteroatom within the vinylogous dienoxy silane donor heavily impacts the diastereocontrol, with syn-configured aldol adducts emerging from pyrroles bearing electron- withdrawing N-protecting groups (Boc, Ts, and Cbz) and anti-configured adducts prevailing when furan- or N-alkyl/alkenylpyrrole donors are involved.
Uncatalyzed, diastereoselective vinylogous Mukaiyama aldol reactions on aqueous media: Pyrrole vs furan 2-silyloxy dienes
Curti, Claudio,Battistini, Lucia,Zanardi, Franca,Rassu, Gloria,Zambrano, Vincenzo,Pinna, Luigi,Casiraghi, Giovanni
supporting information; experimental part, p. 8681 - 8684 (2011/02/26)
The first uncatalyzed, diastereoselective vinylogous Mukaiyama aldol reaction is reported, between pyrrole/furan-based dienoxy silanes and aromatic aldehydes on salty water/methanol medium, at almost human body temperature, under ultrasonic irradiation. W
