Alhaffar Mouheddin T, Akhtar Mohammad N, Ali Shaikh A
Chemistry Department, King Fahd University of Petroleum & Minerals Dhahran 31261 Saudi Arabia
Center for Refining and Petrochemicals, RI, King Fahd University of Petroleum & Minerals Dhahran 31261 Saudi Arabia.
RSC Adv. 2019 Jul 9;9(37):21265-21277. doi: 10.1039/c9ra04719k. eCollection 2019 Jul 5.
Naturally occurring safrole I upon epoxidation gave safrole oxide II, which underwent ring opening polymerization using a Lewis acid initiator/catalyst comprising of triphenylmethylphosphonium bromide/triisobutylaluminum to afford new polyether III in excellent yields. Epoxy monomer II and allyl glycidyl ether IV in various proportions have been randomly copolymerized to obtain copolymer V. A mechanism has been proposed for the polymerization reaction involving chain transfer to the monomers. A strategy has been developed for the deprotection of the methylene acetal of V using Pb(OAc) whereby one of the methylene protons is replaced with a labile OAc group to give VI. The pendant allyl groups in VI have been elaborated a thiol-ene reaction using cysteamine hydrochloride and thioglycolic acid to obtain cationic VII and anionic VIII polymers, both containing a mussel-inspired Dopa-based catechol moiety. During aqueous work up, the protecting group containing OAc was deprotected under mild conditions. Cationic VII and anionic VIII were also obtained an alternate route using epoxide IX derived from 3,4-bis[-butyldimethylsilyloxy]allylbenzene. Monomer IX was homo- as well as copolymerized with IV using Lewis acid initiator/catalyst system to obtain homopolymer X and copolymer X1. Copolymer XI was then elaborated using a thiol-ene reaction followed by F catalysed silyl deprotection to obtain mussel inspired polymers VII and VIII, which by virtue of having charges of opposite algebraic signs were used to form their coacervate.
天然存在的黄樟素I经环氧化得到黄樟素氧化物II，后者使用由三苯基甲基溴化鏻/三异丁基铝组成的路易斯酸引发剂/催化剂进行开环聚合，以优异的产率得到新型聚醚III。环氧单体II和烯丙基缩水甘油醚IV以不同比例进行无规共聚以获得共聚物V。已提出了涉及向单体链转移的聚合反应机理。已开发出一种使用Pb(OAc)对V的亚甲基缩醛进行脱保护的策略，由此亚甲基质子之一被不稳定的OAc基团取代以得到VI。VI中的侧链烯丙基已通过使用盐酸半胱胺和巯基乙酸的硫醇-烯反应进行修饰，以获得阳离子聚合物VII和阴离子聚合物VIII，二者均含有受贻贝启发的基于多巴的儿茶酚部分。在水相后处理过程中，含OAc的保护基团在温和条件下被脱保护。阳离子聚合物VII和阴离子聚合物VIII也可通过使用由3,4-双[-丁基二甲基硅氧基]烯丙基苯衍生的环氧化物IX的另一条路线获得。单体IX使用路易斯酸引发剂/催化剂体系进行均聚以及与IV共聚，以获得均聚物X和共聚物X1。然后通过硫醇-烯反应，接着进行F催化的硅基脱保护来修饰共聚物XI，以获得受贻贝启发的聚合物VII和VIII，它们由于带有相反代数符号的电荷而被用于形成它们的凝聚层。
