Reference of 51376-06-8,Some common heterocyclic compound, 51376-06-8, name is 5-Bromobenzo[c][1,2,5]oxadiazole, molecular formula is C6H3BrN2O, traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
[00779] Intermediate 85: 2,1 ,3-benzoxadiazol-5-amine[00780] In a dry, nitrogen purged 5-10 mL microwave tube were successivelly introduced 5-bromo-2,1 ,3-Benzoxadiazole (200mg, 1.01 mmol), Pd2(dba)3 (46mg, 0.OSmmol) and tri-tertbutylphosphonium tetrafluoroborate (58mg, 0.2Ommol) and toluene (1 mL). The tube was evacuated/backfilled with nitrogen and then sealed. Lithium bis(trimethylsilyl)amide (1.0 M in toluene, 2mL, 2mmol) was added and the reaction mixture was thermally heated at 50 C overnight. After cooling to room temperature, the reaction mixture was diluted with ether (2OmL) and thesilylamide was deprotected by adding 2-3 drops of 1 M HCI(aq). The mixture was transferred to a separatory funnel and washed with sat. aq. NaHCO3 (lOmL). The organic layer was dried over Na2504, filtered and concentrated in vacuo. The residue was purified via column chromatography using an eluent of 0-100% EtOAc in heptane. Three main fractions were collected containing the expected product and unprotected I partially deprotecetd silyl amide. The fractions were pooled,concentrated in vacuo and the residue dissolved in THF (1 mL). 1 M HCI(aq) (1 mL) was added and the mixture was stirred at room temperature for 1 hour. The mixture was made alkaline with 1 M NaOH(aq) and extracted with EtOAc (3 x 1 OmL). The combined organic layers were washed with brine (l0mL), dried over Na2SO4 and concentrated in vacuo. The residue was purified via column chromatography using an eluent of 0-100% EtOAc in heptane to give 2,1 ,3-benzoxadiazol-5-amine (57mg, 0.42mmol, 42%) as a yellow-green solid.1H NMR (DMSO-d6, 400MHz) O/ppm: 7.76 (1H, dd, J= 9.5Hz, 0.6Hz), 7.14 (1H, dd, J= 9.5Hz,1.8Hz), 6.43 (2H, brs), 6.35 (1H, dd, J= 1.8Hz, 0.6Hz).MS Method 2: RT: 1.22 mi mlz 136.0 [M+H]
The synthetic route of 51376-06-8 has been constantly updated, and we look forward to future research findings.
Reference:
Patent; REDX PHARMA PLC; ARMER, Richard; BELFIELD, Andrew; BINGHAM, Matilda; JOHNSON, Alice; MARGATHE, Jean-Francois; AVERY, Craig; HUGHES, Shaun; MORRISON, Angus; (278 pag.)WO2016/51193; (2016); A1;,
Bromide – Wikipedia,
bromide – Wiktionary