51528-22-4Relevant articles and documents
Healable network polymers bearing flexible poly(lauryl methacrylate) chains via thermo-reversible furan-maleimide diels–alder reaction
Patil, Sachin S.,Torris, Arun,Wadgaonkar, Prakash P.
, p. 2700 - 2712 (2017)
A new ATRP initiator containing two furyl rings, namely, bis(furan-2-ylmethyl) 2-bromopentanedioate was synthesized starting from commercially available l-glutamic acid as a precursor. Well-defined bisfuryl-terminated poly(lauryl methacrylate) macromonomers with molecular weight and dispersity in the range 5000–12,000 g mol?1 and 1.30–1.37, respectively, were synthesized employing the initiator by atom transfer radical polymerization (ATRP). Independently, 1,1′,1″-(nitrilotris(ethane-2,1-diyl))tris(1H-pyrrole-2,5-dione) was synthesized as a tris-maleimide counterpart for furan-maleimide click reaction. Thermo-reversible network polymer bearing flexible poly(lauryl methacrylate; (PLMA) chains was obtained by furan-maleimide Diels–Alder click reaction of bisfuryl-terminated PLMA with 1,1′,1″-(nitrilotris(ethane-2,1-diyl))tris(1H-pyrrole-2,5-dione). The prepared network polymer showed retro-Diels–Alder reaction in the temperature range 110–170 °C as determined from DSC analysis. The presence of low Tg (–40 °C) PLMA chains induced chain mobility to the network structure which led to the complete scratch healing of the coating at 60 °C in five days due to furan-maleimide adduct formation. The storage modulus of the network polymer was found to be 3.7 × 104 Pa at the constant angular frequency of 5 rad/sec and strain of 0.5%. The regular reversal of storage (G′) and loss modulus (G″) was observed with repeated heating (40 to 110 °C) and cooling cycles (110 to 40 °C) at constant angular frequency and strain.
GADOLINIUM BEARING PCTA-BASED CONTRAST AGENTS
-
Page/Page column 29-30, (2020/03/02)
The present invention relates to the RRR/SSS pair of enantiomers of the of Gd(PCTA-tris-glutamic acid), the single enantiomers of the pair, the pharmaceutically acceptable salts thereof, their amide derivatives, and compositions comprising at least 50% of these compounds.
Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
supporting information, p. 17662 - 17668 (2015/02/02)
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
