Hydrazine hydrate (1:1) → 2-{2-[(4-Bromophenyl)sulfonyl]phenyl}-1,3,4-oxadiazole

Temperature

90 °C

Methyl 2-[(4-bromophenyl)sulfonyl]benzoate (Example 144 Step 1; 150 mg, 0.46 mmol) and hydrazine hydrate (0.06 mL, 2.32 mmol) were stirred together at room temperature for 1.5 h then at 90° C. for 2 h. The excess hydrazine was removed in vacuo and the residue was dissolved in triethylorthoformate (4.6 mL) with catalytic camphorsulfonic acid and the mixture heated at 90° C. overnight. The cooled reaction mixture was partitioned between EtOAc and water and the organic layer was washed with brine and evaporated in vacuo. The residue was purified by flash column chromatography on silica (eluant 50% EtOAc/isohexane) to yield 2-{2-[(4-bromophenyl)sulfonyl]phenyl}-1,3,4-oxadiazole (60 mg, 35%). δH (400 MHz, d6 DMSO): 9.42 (1H, s), 8.35–8.33 (1H, m), 7.97–7.91 (2H, m), 7.86–7.84 (3H, m), 7.80–7.78 (2H, m).

1. customThe excess hydrazine was removed in vacuo
2. dissolutionthe residue was dissolved in triethylorthoformate (4.6 mL) with catalytic camphorsulfonic acid
3. customThe cooled reaction mixture
4. customwas partitioned between EtOAc and water
5. washthe organic layer was washed with brine
6. customevaporated in vacuo
7. customThe residue was purified by flash column chromatography on silica (eluant 50% EtOAc/isohexane)

ORD record

ord-aafe85264a0f49a8ada9926e4b2bd49e

Source dataset

uspto-grants-2007_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07217740B2