1,3-benzenediboronic acid

Recently conjugated polyelectrolytes containing alkylsulphonic and alkyl-phosphonic groups have received considerable interest [176-180]. Sulfonate-substituted poly(p-phenylene) was prepared [ 176] using Suzuki co-polymerisation of 1,4-benzenediboronic acid with sulfonate monomer in three steps starting from 1,4-dimethoxybenzene ... 

The design and synthesis routes of COF materials mentioned above have been widely used in practical applications, and a series of new materials have been developed. For example, the self-condensation reaction of 1,4-benzenediboronic acid (2D-C2) forms the 2D COF-1 (Figure 6.2a). The cocondensation reaction between 1,3,5-benzene boronic acid (BTBA 2D-C3) and 2,3,6,7,10,ll-hexahydro3ytriphenylene (HHTP 2D-C3) produced 2D COF-6 (Figure 6.2d), and the co-condensation reaction between HHTP and... 

The first water-soluble, electroactive, self-doped sulfonatoalkoxy-substituted PPP, poly[2,5-bis(3-sulfonatopropoxy)-l,4-phenylene-aZf-l,4-phenylene] (55), was synthesized from 1,4-benzenediboronic acid [4612-26-4] (56) and the disodium salt of l,4-dibromo-2,5-bis(3-sulfonatopropoxy)benzene (57) by the homogeneous Suzuki coupling method (130). The polymer purified by dialysis of an aqueous solution was composed exclusively of 1,4-linkages. The abihty to utilize a variety of bis(boronic acids) in this polymerization with sulfonate containing aiyl hahdes will lead to a high degree of structural control of the optoelectronic properties of these water-soluble poljnners. 

While oxidation of the benzenediboronic acids with alkaline hydrogen peroxide affords the corresponding 1,3- and 1,4-dihydroxybenzenes (70-72%), the pyridinediboronic acids lead via a double Pd(0) catalyzed Suzuki reaction with 4-iodoanisole to 2,5- and 2,6-Z /s-(4-methoxyphenyl)pyridines (Sch. 36) [107]. 

Figure 10.2 Self-healing of the gel formed by complexation of a branched catechol derivatized poly(ethylene glycol) with 1,3-benzenediboronic acid. The gel was formed into a cube (a), cut into two pieces (b), fused together (c), and then stretched without fracture 30 s after fusion (d). (Reproduced from ref. 54 with permission from The Royal Society of Chemistry.)...

The preparation of all three substitution patterns of benzenediboronic acid has been reported (Figure 1.20). Whereas the preparation of the 1,4- and 1,3-benzenediboron-ic acids 76 and 77 from the corresponding dibromides were well described [157a, 218], that of the ortho isomer 78 is more tedious [72, 219]. Several other mono- and polycyclic aromatic diboronic acids, such as 79 [150], 80 [220], and 81 [221], have been described. 

He et al. (2011) synthesized a pH-responsive hydrogel based on bor-onate-catechol complexation using 1,3-benzenediboronic acid and catechol end groups present on 4-arm PEG catechol (cPEG) (Fig. 8.5). Under basic aqueous conditions, the 1,3-benzenediboronic acid establishes a tetrahedral borate ester with the catechol end moieties of 4-arm PEG catechol and forms a three-dimensional, pH-responsive smart hydrogel. 

Noguchi H, Shioda T, Chou CM, Suginome M. Differentially protected benzenediboronic acids divalent cross-coupling modules for the efficient synthesis of boron-substituted oligoarenes. Org Lett. 2008 10 377-380. 

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