57609-67-3Relevant academic research and scientific papers
Synthesis, characterization and morphological studies of some novel siloxane-based block copolymeric materials containing organometallic as well as organic polyesteramides
Saif Ullah Khan, Muhammad,Akhter, Zareen,Iqbal, Naseer,Siddiq, Mohammad
, p. 312 - 328 (2013)
A series of semi-aromatic diamine monomers (1,m-bis (4-amino benzoyloxy) alkanes; m = 2-6) having in-built ester linkages with variable methylene spacers were synthesized in two steps from aliphatic diols and p-nitrobenzoyl chloride and characterized by their melting points, elemental analysis, FTIR, 1H and 13C NMR spectroscopic studies. The diamines were then polymerized in-situ with ferrocene-based organometallic and terephthaloyl- as well as isophthaloyl-based organic acyl chlorides along with telechelic polydimethylsiloxane oligomer to produce a novel set of ferrocene-containing siloxane-based block copolymers and their organic analogues. The corresponding polyesteramides of the synthesized copolymers, without siloxane segment, were also prepared for comparative studies. The structural features of the organometallic and organic block copolymers along with their respective polyesteramides were confirmed by their physical properties and spectroscopic studies. The molecular parameters of all these materials were determined by static laser light scattering (LLS) technique and glass transition temperatures (Tg) were obtained by differential scanning calorimetry (DSC). The materials were soluble in sulphuric acid and partially soluble in common organic solvents at room temperature, yet become readily soluble upon N-trifluoroacetylation. The morphological information of the synthesized materials was obtained by X-ray diffraction and surface studies (SEM and AFM).
Organocatalytic Double Ugi Reaction with Statistical Amplification of Product Enantiopurity: A Linker Cleavage Approach to Access Highly Enantiopure Ugi Products
Feng, Qi-Yun,Zhu, Jieping,Wang, Mei-Xiang,Tong, Shuo
, p. 483 - 487 (2020/01/21)
Here we report an organocatalytic double Ugi reaction combining the enantioselective process and ee enhancement in a single operation to afford the chiral Ugi products with very high ee values. Both bisisocyanides and bisanilines tethered by carbonate and diester, respectively, were designed to accomplish this double multicomponent reaction that formed 10 new chemical bonds (4 C-N, 2 C-C, 2 C-O, and 2 N-H bonds). The strategy was further applied for the fast construction of an enantiomerically enriched macrocycle.
