Synthetic Route of 21120-91-2, In the next few decades, the world population will flourish. As the population grows rapidly and people all over the world use more and more resources, all industries must consider their environmental impact. 21120-91-2, name is 7-Bromobicyclo[4.2.0]octa-1,3,5-triene belongs to bromides-buliding-blocks compound, it is a common compound, a new synthetic route is introduced below.
Magnesium turnings (210 mg), sodium hydride (29 mg, 60% oil dispersion) and a magnetic stir bar were added to a 100 ml rbf, capped with a rubber septum and placed under vacuum and allowed to stir for 4 hours. A solution of BrBCB (750 mg) in THF (20 ml) was added via syringe slowly. The solution turned bright yellow and was placed under a nitrogen atmosphere. The solution was left to stir for 30 minutes then added via syringe to a 100 ml rbf containing a stir bar, bromostyrene (1 g), Pd PEPPSI-iPr (1,3-Bis(2,6-Diisopropylphenyl)imidazol-2-ylidene)(3-chloropyridyl)palladium(II) dichloride, CAS no: 905459-27-0) catalyst (190 mg, 5 mol %) and THF (15 ml ) under nitrogen and capped with a rubber septum. The mixture turned black after about 30 minutes and was left to stir at room temperature for 12 h. The mixture was added to a separatory funnel containing water (100 ml), and extracted with ethyl acetate (3¡Á100 ml). The combined organics were dried with brine (100 ml) and sodium sulfate, filtered and concentrated in vacuo. The residue was recrystallized in methanol to give the desired product as a colorless solid (203 mg, 18% yield). 1H NMR (500 MHz, Chloroform-d) delta 7.49 (d, J=8.1 Hz, 2H), 7.44-7.26 (m, 6H), 6.84 (dd, J=17.7, 10.8 Hz, 1H), 5.86 (d, J=17.7 Hz, 1H), 5.35 (d, J=10.8 Hz, 1H), 4.86-4.75 (m, 1H), 3.85 (dd, J=13.9, 5.7 Hz, 1H), 3.22 (dd, J=13.9, 2.7 Hz, 1H). A DSC of the resulting monomer showed an exotherm (cure) peak max of 165 C. at a scan rate of 10 C./min. (0070) The yield in the above reaction was very low. Further, no ether linkage resulted from the reaction. However, the cure temperature of the monomer was acceptable.
The synthetic route of 7-Bromobicyclo[4.2.0]octa-1,3,5-triene has been constantly updated, and we look forward to future research findings.
Reference:
Patent; Rohm and Haas Electronic Materials LLC; Hayes, Colin; Gallagher, Michael K.; Riener, Michelle; (10 pag.)US2019/169327; (2019); A1;,
Bromide – Wikipedia,
bromide – Wiktionary