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Amphiphilic Hyperbranched Polymers
Published in Narendra Pal Singh Chauhan, Functionalized Polymers, 2021
Srijoni Sengupta, Prashant Gupta, Priyanka Sengupta, Ayan Dey
In another experimental work, Chen and his team developed an amphiphilic copolymer based on hydrophilic PEG and hydrophobic β-amino ester. First, in the presence of 4-(amino methyl) piperidine (AMP) and 1,6-hexanediol diacrylate (HDDA) β-amino ester was reacted by Michael Addition reaction at 60°C to generate a hyperbranched structure. In the second step, the residual acrylate of the hyperbranched β-amino ester groups reacted with PEG-NH2 to obtain the amphiphilic structure (Chen et al. 2013). At pH ~7 the hyperbranched copolymer is able to self-assemble to form micelle with PEG at outward shell and hyperbranched amino ester at the core. Under UV irradiation, the micelles were crosslinked. The micelles were pH sensitive, highly sensitive, and proved to be highly efficient as an anti-cancerous drug delivery vehicle.
Biological Stimulus-Responsive Hydrogels
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
A.K. Bajpai, Sanjana Kankane, Raje Chouhan, Shilpi Goswami
Cationic hydrogels swell and release a drug in the low pH environment of the stomach. When external pH is lower than the pKb of the ionizable groups, cationic hydrogels protonate and swell more (Lin and Metters, 2006). Typical examples of the basic polyelectrolytes include poly(tertiary amine methacrylate) such as poly(2-(dimethylamino)ethylmethacrylate) (Dieudonne et al., 2006) and poly(2-(diethylamino)ethylmethacrylate), poly(2-vinylpyridine), and biodegradable poly(β-amino ester).
Combinatorial Polymer and Lipidoid Libraries for Nanomedicine
Published in Vladimir Torchilin, Mansoor M Amiji, Handbook of Materials for Nanomedicine, 2011
Jordan J. Green, Robert Langer, Daniel G. Anderson
We have previously shown that poly(beta-amino ester)s (PBAEs) are a promising class of cationic polymers for gene delivery. PBAEs are hydrolytically degradable, have low cytotoxicity, and electrostatically bind DNA to form gene delivery nanoparticles.27–30 They are synthesized in one step by the conjugate addition of amine monomers to diacrylates as shown in Fig. 7.1 without the production of byproducts. Amine and diacrylate monomers are inexpensive and commercially available which enables the facile synthesis of a structurally diverse library. Initial synthesis was performed one-by-one in glass vials using solvent that later needed to be removed (THF or methylene chloride).45,46 To scale up to a much larger library, it was important to change to a semi-automated synthesis that did not use a toxic solvent.
Transition-metal-free electrochemical-induced active C(sp3)-H functionalization
Published in Green Chemistry Letters and Reviews, 2023
Xiaolong Ma, Jinfeng Wei, Xu Yang, Huajin Xu, Yi Hu
In 2021, Kumar’s group reported an efficient electrochemical protocol for intermolecular oxidative C(sp3)-H/N–H cross-coupling to synthesize α–amino α–aryl esters (84). Methyl 2-(3-chlorophenyl) acetate (74) and pyrrolidine (75) displayed in Scheme 24 were employed as model substrates to obtain the optimal conditions of the reaction. In this case, the desired product α-amino ester (76) was offered in 89% yield at room temperature with the combination of KI (0.5 equiv) and LiClO4 (1.0 equiv) as electrolytes under 8.0 mA constant current. Unfortunately, the substrate scope of this protocol is limited to α-aryl acetates and secondary aliphatic amines. Under the optimal conditions aniline(s)/primary/secondary aromatic amines or sterically hindered aromatic esters/acids/amide were unable to offer corresponding products.
Morphology-dependent antibacterial properties of diamond coatings
Published in Functional Diamond, 2022
Ruoying Zhang, Yuting Zheng, Jinlong Liu, Chengming Li, Chengke Chen, Xiaojun Hu, Jinlong Li, Ran Liu, Haitao Ye
For MCD, there is a clear peak around 2850–3000 cm−1 which has three vibration peaks due to C–CH, -CH3, and -CH2 bond, and the peaks around 2750 cm−1 to 2500 cm−1 show the presence of –CH3 and = CH2 functional groups resulting from the as-grown hydrogen terminations, with the hydroxyl situated around 3400 cm−1. Meanwhile, the peaks situated at 1558, 1576, 1615, and 1636 cm−1 are attributed to –NH stretching bonds, and their attributed bending bands typical of the carboxyl group and C = O stretching band of ester were located at 1716, 1733, and 1749 cm−1, respectively. Thus, the spectra of FTIR confirm the existence of -CH2, CH3, amino, ester, carboxyl, and hydroxyl on the MCD surface.
Solid-phase synthesis of sulfur containing heterocycles
Published in Journal of Sulfur Chemistry, 2018
The isocyanates, alkyl halides, and amines were used as building blocks for the SPS of thiazolo[4,5-d]pyrimidine-5,7-diones (Scheme 30). The amino ester resin was reacted with isocyanate under MW irradiation to provide thiazolourea resin. An intermediate was afforded by one-pot cyclization/N-alkylation of the thiazolourea resin in the presence of sodium hydride in dimethylformamide base. The formed intermediate produced the desired thiazolo[4,5-d]pyrimidine-5,7-dione resin via in situ N-alkylation with an alkyl halide. The resin was oxidized to form the sulfone group. The sulfone group furnished the target 2,4,6-trisubstituted thiazolo[4,5-d]pyrimide-5,7-dione derivatives by nucleophilic C-2 substitution with corresponding amines [62,63].