28537-69-1Relevant articles and documents
X-ray crystallographic analysis and DFT calculations of three ‘propylene linker’ dimers linked by one polystep reaction
Shi, Yan,Tan, Xue-Jie,Xing, Dian-Xiang,Sui, Qi-Cheng,Liu, Bin,Feng, Wen-Quan,Liu, Yun
, p. 126 - 135 (2017)
In this manuscript, we report the synthesis, NMR and single-crystal structures of three propylene linking dimers related with the hydrolytic degradation of one 5,6-dehydronorcantharimide dimer. Special attention was paid to the conformation of propylene linkers in order to understand their changes in the reaction. Statistical analysis of CSD database revealed that a-a, g-a and g-g conformations may have similar stability in most cases and various complicated unpredictable non-covalent interactions may play important role in the formation of final rotamers. In order to reproduce all stable conformations and the energy barriers separating them, full range two-dimensional fully relaxed potential-energy surfaces (PES) scans of six ‘propylene linker’ dimers were calculated starting from the most stable crystal structures. The PES were scanned along both bridge C[sbnd]C single bond torsional angles (denoted as θ1 and θ2), while all other internal coordinates were optimized at the DFT/B3LYP/3-21G* level in gas phase. Then all energy minima were re-optimized again at the DFT/B3LYP/6-311 + G(d,p) level both in gas and ethanol solutions in order to evaluate the really stable rotamers. At last, 1D or 2D relaxed PES scans were performed between local stable rotamers to get reliable energy barriers. This method represents a less time-consuming and more reliable approach to the determination of conformational stability of propanediyl bridging chains. The combination of experimental, statistical and theoretical results shows that the observed conformation is jointly determined by the energy levels of the minima, energy barriers separating them, non-covalent interactions and somewhat randomness.
Rubber anti-reversion agent 1,3-bis(maleimido)-n-propane and synthesis method thereof
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Paragraph 0024-0033, (2019/11/20)
The invention provides a rubber anti-reversion agent 1, 3-bis(maleimido)-n-propane and a synthesis method thereof, and the synthesis method comprises the following steps: step 1, adding 1,3-propanediamine and a solvent acetic acid into a reaction kettle together, additionally taking acetic acid to dissolve maleic anhydride, slowly dropwise adding a maleic anhydride solution in a stirring state, and carrying out a heat preservation reaction; step 2, after the heat preservation reaction is finished, adding a catalyst and a dehydrating agent into the reaction kettle, and carrying out acylation reaction; and step 3, after the acylation reaction is finished, centrifuging and filtering reactants, and washing and drying the filter cake to obtain the product. Relatively cheap 1,3-propanediamine isused as a reaction substrate, so that the production cost is saved; acetic acid is used as a solvent, a product obtained after acetic anhydride dehydration is also acetic acid, a reaction solvent canbe directly collected through a centrifugal method, a filtrate can be directly applied to next synthesis without treatment, and material waste and generation of a large amount of wastewater are alsoavoided.
An efficient reverse Diels-Alder approach for the synthesis of N-alkyl bismaleimides
Rao, Venkataramanarao,Navath, Suryakiran,Kottur, Mohankumar,McElhanon, James R.,McGrath, Dominic V.
, p. 5011 - 5013 (2013/09/02)
Bismaleimides are useful precursors for Diels-Alder reactions, Michael additions, and thiol-maleimide based conjugation for the synthesis of materials and polymers. Use of bismaleimide cross linkers for generating polymers, bioconjugate molecules, and useful imaging molecules is an active area of research. An efficient and practical synthetic protocol for N-alkyl bis-maleimide cross linkers starting from furan protected maleimide employing a reverse Diels-Alder reaction is reported.
A New Class of Bradykinin Antagonists: Synthesis and in Vitro Activity of Bissuccinimidoalkane Peptide Dimers
Cheronis, John C.,Whalley, Eric T.,Nguyen, Khe T.,Eubanks, Shad R.,Allen, Lisa G.,et al.
, p. 1563 - 1572 (2007/10/02)
A systematic study on the dimerization of the bradykinin (BK) antagonist D-Arg0-Arg1-Pro2-Hyp3-Gly4-Phe5-Ser6-D-Phe7-Leu8-Arg9 has been performed.The first part of this study involved compounds wherein dimerization was carried out by sequentially replacing each amino acid with cysteine and cross-linking with bismaleimidohexane.The second part of this study utilized a series of bissuccinimidoalkane dimers wherein the intervening methylene chain was varied systematically from n = 2 to n = 12 while the point of dimerization was held constant at position 6.The biological activities of these dimers were then evaluated on BK-induced smooth muscle contraction in two different isolated tissue preparations: guinea pig ileum (GPI) and rat uterus (RU).Several of the dimeric BK antagonists displayed remarkable activites and long durations of action.In addition, dimerization at position 4, 7, 8, or 9 produced dimeric analogues with markedly reduced potency.Rank order of antagonist potency as a function of dimerization position is as follows: rat uterus, 6 > 5 > 0 > 2 > 1 >3 >> 4, 7, 8, 9; guinea pig ileum, 6 > 5 > 3 > 2 > 1 > 0 >> 4, 7, 8, 9.Evaluation of the linker length as represented by the number of methylene units indicated an optimal distance between the two monomeric peptides of six to eight methylene moieties.These studies also revealed that the carbon-chain length significantly affected the duration of action in vitro and resulted in partial agonism effects when n > 8.The optimum activity in vitro was achieved with dimerization at position 6 and n = 6 (designated herein as compound 25; alternatively, CP-0127).Similar effects in potency were also seen when the monomeric antagonist D-Arg0-Arg1-Pro2-Hyp3-Gly4-Phe5-Ser6-D-Phe7-Phe8-Arg9 (NPC-567) was dimerized using similar chemistry.These results suggest that the development of BK antagonists of significant therapeutic potential may be possible using a dimerization strategy that can overcome the heretofore limiting problems of potency and in vivo duration of action found with many of the BK antagonists in the literature.
