923-06-8Relevant academic research and scientific papers
Copper-catalyzed cross-coupling of amino acid-derived amides with (Z)-vinyl iodides: Unexpected solvent effect and preparation of plocabulin
Wang, Leiming,Lei, Xinsheng,Wang, Quanrui,Li, Yingxia
, (2021/02/01)
A copper-catalyzed cross-coupling reaction of amino acid-derived amides and (Z)-vinyl iodide was studied to improve a key step in the synthesis of plocabulin, a novel microtubule destabilizer agent of marine origin. The study revealed a profound solvent effect with 1,2-dimethoxyethane (DME), which gave consistently high yields across a large variety of the amide and (Z)-vinyl iodide substrates. The protocol was successfully utilized in the preparation of plocabulin and provided a significantly improved yield.
Stereospecific Nickel-Catalyzed Reductive Cross-Coupling of Alkyl Tosylate and Allyl Alcohol Electrophiles
Alexanian, Erik J.,Tercenio, Quentin D.
supporting information, p. 7215 - 7219 (2021/09/22)
The stereospecific cross-coupling of easily accessed electrophiles holds significant promise in the construction of C-C bonds. Herein, we report a nickel-catalyzed reductive coupling of allyl alcohols with chiral, nonracemic alkyl tosylates. This cross-coupling delivers valuable allylation products with high levels of stereospecificity across a range of substrates. The catalytic system consists of a simple nickel salt in conjunction with a commercially available reductant and importantly represents a rare example of a cross-coupling involving the C-O bonds of two electrophiles.
Stereoselective synthesis of resorcylic acid lactone Cochliomycin B
Nagalatha,Siva Ganesh,Venkat Narsaiah
, (2021/09/22)
The total synthesis of 14-membered resorcylic acid lactone, Cochliomycin B has prescribed, in a convergent manner, from readily available starting materials, D-galactose, L-aspartic acid and ethyl acetoacetate. The key reactions involved in the synthesis are Julia-Kocienski olefination, E-selective Horner-Wadsworth-Emmons olefination and intramolecular lactonization.
Stereoselective total synthesis of obolactones and 7′,8′-dihydroobolactones
Fernandes, Rodney A.,Kumar, Praveen,Saini, Deepak
, p. 18976 - 18982 (2021/10/29)
A concise stereoselective total synthesis of two diastereomeric obolactones and 7′,8′-dihydroobolactones has been achieved using a metal-free catalytic δ-hydroxyalkynone rearrangement, which could provide the required dihydro-γ-pyrone moiety. The desired first stereogenic center was installed through the chiral pool material,l-aspartic acid. Next, the allylation reaction was strategically utilized to provide the requisite olefin bond for the intended ring-closing metathesis, allowing the installation of the remaining dihydro-α-pyrone moiety in the natural products. It also enabled the targeting of both dihydro-α-pyrone diastereomers. Thus, the first stereoselective total synthesis of (+)-7′,8′-dihydroobolactone was accomplished, establishing its structure and absolute configuration.
Nanoprecipitation of biocompatible poly(Malic acid) derivative, its ability to encapsulate a molecular photothermal agent and photothermal properties of the resulting nanoparticles
Bellec, Nathalie,Camerel, Franck,Cammas-Marion, Sandrine,Pluta, Jean-Baptiste,Vargas Guerrero, Marian Gabriela
, (2021/12/27)
Biocompatible nanoparticles (NPs) of hydrophobic poly(benzyl malate) (PMLABe) were prepared by nanoprecipitation. The influence of nanoprecipitation parameters (initial PMLABe, addition rate, organic solvent/water ratio and stirring speed) were studied to optimize the resulting formulations in terms of hydrodynamic diameter (Dh) and dispersity (PDI). PMLABe NPs with a Dh of 160 nm and a PDI of 0.11 were isolated using the optimized nanoprecipitation conditions. A hydrophobic near infra-red (NIR) photothermally active nickel-bis(dithiolene) complex (Ni8C12) was then encapsulated into PMLABe NPs using the optimized nanoprecipitation conditions. The size and encapsulation efficiency of the NPs were measured, revealing that up to 50 weight percent (wt%) of Ni8C12 complex can efficiently be encapsulated with a slight increase in Dh of the corresponding Ni8C12-loaded NPs. Moreover, we have shown that NP encapsulating Ni8C12 were stable under storage conditions (4?C) for at least 10 days. Finally, the photothermal properties of Ni8C12-loaded NPs were evaluated and a high photothermal efficiency (62.7 ± 6.0%) waswas measured with NPs incorporating 10 wt% of the Ni8C12 complex.
Preparation method of antirust agent 2-(1, 3-benzothiazole-2-sulfenyl) succinic acid
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Paragraph 0034-0037; 0045-0048, (2020/07/12)
The invention discloses a preparation method of an antirust agent 2-(1, 3-benzothiazole-2-sulfenyl) succinic acid. The method is characterized in that L-aspartic acid is taken as a raw material, bromosuccinic acid is synthesized through diazotization bromination reaction, bromo succinic acid and 2-mercaptobenzothiazole are subjected to nucleophilic substitution reaction, and a product is acidified, filtered and washed to obtain 2-(1, 3-benzothiazole-2-sulfenyl) succinic acid. Wherein a water phase for producing bromo succinic acid can be used for the acidification process of 2-(1, 3-benzothiazole-2-sulfenyl) sodium succinate in the next step, and a water phase after acidification can be reused for producing bromo succinic acid. A water phase of a whole reaction system can be recycled, thedischarge amount of wastewater is greatly reduced, the wastewater after multiple cycles can be used for extracting sodium salt or liquid bromine, the produced 2-(1, 3-benzothiazole-2-sulfenyl) succinic acid product has high purity, and the purity can reach 97% through high performance liquid chromatography detection. The whole reaction system is environment-friendly, pollution-free, high in atomutilization efficiency, simple in process operation, high in yield and particularly suitable for industrial production.
Stereoselective total synthesis of C2-symmetric natural products pyrenophorol and its derivatives
Narala, Siva Ganesh,Nagalatha,Venkat Narsaiah
supporting information, p. 2173 - 2178 (2019/03/11)
A stereoselective total synthesis of 16-membered C2-symmetric macrodiolide Pyrenophorol, Tetrahydropyrenophorol and 4,4-diacetylpyrenophorol have been accomplished. The synthesis started from commercially available L-Aspartic acid and the key reactions involved are regioselective epoxide opening, CBS reduction, Pinnick oxidation and Mitsunobu dilactonization.
Synthesis and Evaluation of Novel TLR2 Agonists as Potential Adjuvants for Cancer Vaccines
Lu, Benjamin L.,Williams, Geoffrey M.,Verdon, Daniel J.,Dunbar, P. Rod,Brimble, Margaret A.
supporting information, p. 2282 - 2291 (2019/10/02)
Cancer immunotherapy has gained increasing attention due to its potential specificity and lack of adverse side effects when compared to more traditional modes of treatment. Toll-like receptor 2 (TLR2) agonists are lipopeptides possessing the S-[2,3-bis(palmitoyloxy)propyl]-l-cysteine (Pam2Cys) motif and exhibit potent immunostimulatory effects. These agonists offer a means of providing "danger signals" in order to activate the immune system toward tumor antigens. Thus, the development of TLR2 agonists is attractive in the search of potential immunostimulants for cancer. Existing SAR studies of Pam2Cys with TLR2 indicate that the structural requirements for activity are, for the most part, very intolerable. We have investigated the importance of stereochemistry, the effect of N-terminal acylation, and homologation between the two ester functionalities in Pam2Cys-conjugated lipopeptides on TLR2 activity. The R diastereomer is significantly more potent than the S diastereomer and N-terminal modification generally lowers TLR2 activity. Most notably, homologation gives rise to analogues which are comparatively active to the native Pam2Cys containing constructs.
PEPTIDE CONJUGATES, CONJUGATION PROCESS, AND USES THEREOF
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Page/Page column 135, (2019/03/17)
The invention relates to peptide conjugates, methods for making peptide conjugates, conjugates produced by the methods, and pharmaceutical compositions comprising the conjugates. Methods of eliciting immune responses in a subject and methods of vaccinating a subject, uses of the conjugates for the same, and uses of the conjugates in the manufacture of medicaments for the same are also contemplated.
Site-Selective Conversion of Azido Groups at Carbonyl α-Positions to Diazo Groups in Diazido and Triazido Compounds
Yokoi, Taiki,Tanimoto, Hiroki,Ueda, Tomomi,Morimoto, Tsumoru,Kakiuchi, Kiyomi
, p. 12103 - 12121 (2018/10/09)
This paper reports on the selective conversion of alkyl azido groups at the carbonyl α-position to diazo compounds. Through β-elimination of dinitrogen, followed by hydrazone formation/decomposition, α-azidocarbonyl moieties were transformed into α-diazo carbonyl groups in one step. As these reaction conditions do not involve aryl or general alkyl azides, site-selective conversions of di- and triazides were achieved. Through this method, the successive site-selective conjugation of the triazido molecule with three different components is demonstrated.
