Yam Code

New Paste Browse

https://www.selleckchem.com/products/wortmannin.html A green strategy for the synthesis of nonisocyanate polyester-urethanes (NIPHEUs) was developed. These NIPHEUs were synthesized by step growth polymerization combining sugar-derived dimethyl-2,5-furan dicarboxylate (DMFD) with polyhydroxylurethanes (PHUs) adducts bearing four hydroxyl groups. The later hydroxyl urethane tetraols (HU-tetraols) building blocks were prepared by aminolysis of glycerol carbonate with two different aliphatic diamines having different chain lengths, 8 and 12 carbons. Qualitative and quantitative NMR analyses of the HU-tetraols showed the presence of primary and secondary hydroxyl moieties at different ratios. Hence, in the polycondensation stage, the stoichiometry of the diester was varied from 1 to 6 equiv in order to tailor the structural features of the prepared NIPHEUs. The success of the chain extension through polycondensation was confirmed by FTIR and NMR analyses. Thermal analyses of these new polymers demonstrated satisfactory thermal stability, with onset degradation temperatures ranging from 170 to 220 °C where the main first degradation stage occurs. Their melting temperatures ranged between 93 and 110 °C and seem to be driven by the thermal behavior of HU-tetraol monomers. Surprisingly, preliminary results from thermal analyses revealed the occurrence of a striking thermal change in the NIPHEUs upon repetitive heating cycles. This behavior may be related to a thermal-induced bond exchange probably driven by transcarbamoylation reaction. Such interesting vitrimer-like behavior for this new type of NIPHEUs would be unique and should be confirmed by a deeper study before leading to a new range of functional green materials.A rigid chiral acyclic chelator H2CHXhox was synthesized and evaluated for Ga3+-based radiopharmaceutical applications; it was compared to the previously reported hexadentate H2hox to determine the effect of a backbone reinforced from adding a chiral 1S,2S-tr

Paste Settings

Paste Title : [Optional]

Paste Folder : [Optional]

Syntax Highlighting : [Optional]

Paste Expiration : [Optional]

Paste Status : [Optional]

Password : [Optional]

Description: [Optional]

Tags: [Optional]

Encrypt Paste (?)

You are currently not logged in, this means you can not edit or delete anything you paste. Sign Up or Login

Paste Settings

Site Languages