20859-23-8Relevant articles and documents
Block and star block copolymers by mechanism transformation. 7. Synthesis of polytetrahydrofuran/poly(1,3-dioxepane)/polystyrene ABC miktoarm star copolymers by combination of CROP and ATRP
Feng, Xiao-Shuang,Pan, Cai-Yuan
, p. 2084 - 2089 (2002)
Polytetrahydrofuran (PTHF)/poly(1,3-dioxepane) (PDOP)/polystyrene (PSt) ABC miktoarm star copolymers were synthesized by combination of cationic ring-opening polymerization (CROP) and atom transfer radical polymerization. TWO different functional groups, carboxylic acid and CHBr, were capped at one end of PTHF through the reaction of PTHF-OH with 2-bromosuccinic anhydride (BSA). After PTHF-OOCCHBrCH2COOH reacted with thionyl chloride, block copolymer PTHF-b-PDOP was synthesized by CROP of DOP at -30 to -35 °C with PTHF-OOCCHBrCH2COCl and AgClO4 as catalyst. Finally, (PTHF) (PDOP)-Br was used to initiate the polymerization of St in the presence of CuBr and bipyridine at 110 °C, and ABC miktoarm star polymer, s-[(PTHF) (PDOP) (PSt)] was successfully prepared. The copolymers obtained were characterized by 1H NMR and gel permeation chromatography measurements.
Identification and pharmacological characterization of succinate receptor agonists
Geubelle, Pierre,Gilissen, Julie,Dilly, Sébastien,Poma, Laurence,Dupuis, Nadine,Laschet, Céline,Abboud, Dayana,Inoue, Asuka,Jouret, Fran?ois,Pirotte, Bernard,Hanson, Julien
, p. 796 - 808 (2017)
Background and Purpose: The succinate receptor (formerly GPR91 or SUCNR1) is described as a metabolic sensor that may be involved in homeostasis. Notwithstanding its implication in important (patho)physiological processes, the function of succinate receptors has remained ill-defined because no pharmacological tools were available. We report on the discovery of the first family of potent synthetic agonists. Experimental Approach: We screened a library of succinate analogues and analysed their activity on succinate receptors. Also, we modelled a pharmacophore and a binding site for this receptor. New agonists were identified based on the information provided by these two approaches. Their activity was studied in various bioassays, including measurement of cAMP levels, [Ca2+]i mobilization, TGF-α shedding and recruitment of arrestin 3. The in vivo effects of activating succinate receptors with these new agonists was evaluated on rat BP. Key Results: We identified cis-epoxysuccinic acid and cis-1,2-cyclopropanedicarboxylic acid as agonists with an efficacy similar to that of succinic acid. Interestingly, cis-epoxysuccinic acid was 10- to 20-fold more potent than succinic acid on succinate receptors. For example, cis-epoxysuccinic acid reduced cAMP levels with a pEC50?=?5.57?±?0.02 (EC50?=?2.7?μM), compared with succinate pEC50?=?4.54?±?0.08 (EC50?=?29?μM). The rank order of potency of the three agonists was the same in all in vitro assays. Both cis-epoxysuccinic and cis-1,2-cyclopropanedicarboxylic acid were as potent as succinate in increasing rat BP. Conclusions and Implications: We describe new agonists at succinate receptors that should facilitate further research on this understudied receptor.
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 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.
