Study On Selective THP Protection And Esterification Of 2-(Hydroxymethyl)-1,4-Benzenediol

Thermotropic liquid crystal is widely used in flat panel display. In this work, acrylic ester liquid crystal intermediate 2-[[(Tetrahydro-2H-pyran-2-yl)oxy]methyl]-1,4-benzenediol was systematic studied. The main job is exploring a cheap and commercially available material which can be used for synthesizing liquid crystal intermediate. The titled compound was synthesized after esterification. The main content of the thesis was as following:1. With polyethylene glycol (PEG) as the solvent,2-(Hydroxymethyl)-1,4-benzenediol was synthesized from hydroquinone and paraformaldehyde. The process was optimized and simplified. The highest yield can reach up to 48.27% and the product structure was confirmed by 1H-NMR and 13C-NMR.2. The tetrahydropyran ether (THP) was obtained by the reaction of the 3,4-dihydro pyran and hydroxyl group with catalyst. According to the above method, liquid crystal intermediate 2-[[(Tetrahydro-2H-pyran-2-yl)oxy]methyl]-1,4-benzenediol was synthesized. A variety of catalysts were tried during these experiments. The highest yield of 40.82% was obtained by using pyridiniump-toluenesulfonate as the catalyst. The important intermediate compounds were identified by IR,1H-NMR and 13C-NMR.3.2-[[(Tetrahydro-2H-pyran-2-yl)oxy]methyl]-4-methoxybenzoic acid-1,4-phenylene ester was synthesized from 2-[[(Tetrahydro-2H-pyran-2-yl)oxy]methyl]-1,4-benzenediol and methoxybenzoic acid via esterification reaction, with the DIC and DMAP as catalysts. The product yield can reach 40.80% and the structure was also confirmed by 1H-NMR and 13C-NMR.4.2-[[(Tetrahydro-2H-pyran-2-yl)oxy]methyl]-4-butoxybenzoic acid-1,4-phenylene ester was synthesized from 2-[[(Tetrahydro-2H-pyran-2-yl)oxy]methyl]-1,4-benzenediol and our own new synthetic butoxybenzoic acid via esterification reaction. With the DCC and DMAP as catalysts, the product yield can reach 43.21%. The structure was identified by IR,1H-NMR and 13C-NMR.There are some advantages of this novel synthetic method, such as cheap available material,mild reaction condition and simple operation. Moreover, the method described above can synthesize a lot of liquid crystal molecules and reduce the cost of the synthesis of liquid crystal molecules.