Potassium Carbonate → tert-butyl 3-(1H-indol-5-yl)-1,2,4-thiadiazol-5-ylcarbamate

HRID 634260Notes

Reaction equation

HRID 634260 reaction equation
Br[C:2]1[N:6]=[C:5]([NH:7][C:8](=[O:14])[O:9][C:10]([CH3:13])([CH3:12])[CH3:11])[S:4][N:3]=1.[NH:15]1[C:23]2[C:18](=[CH:19][C:20](B(O)O)=[CH:21][CH:22]=2)[CH:17]=[CH:16]1.C([O-])([O-])=O.[K+].[K+]>O1CCOCC1.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[NH:15]1[C:23]2[C:18](=[CH:19][C:20]([C:2]3[N:6]=[C:5]([NH:7][C:8](=[O:14])[O:9][C:10]([CH3:13])([CH3:12])[CH3:11])[S:4][N:3]=3)=[CH:21][CH:22]=2)[CH:17]=[CH:16]1

Participants

6

Reactant 3

HCID 11430Potassium CarbonateHCID 27343615-Indolylboronic acidHCID 44604453tert-Butyl (3-bromo-1,2,4-thiadiazol-5-yl)carbamate

Product 1

HCID 68356726tert-butyl 3-(1H-indol-5-yl)-1,2,4-thiadiazol-5-ylcarbamateYield 44.2%

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 312751,4-DioxaneSolvent

Procedure

To a mixture of tert-butyl (3-bromo-1,2,4-thiadiazol-5-yl)carbamate (100 mg, 0.359 mmol) and indole-5-boronic acid (57.9 mg, 0.359 mmol) in 1,4-dioxane (5 mL) was added Pd(PPh3)4 (20.77 mg, 0.017 mmol) and 1M aq K2CO3 solution (0.539 mL, 0.539 mmol). N2 gas was purged for 15 min. After 15 min, the reaction was heated at reflux for 4 h. The reaction mixture was cooled to RT and treated with H2O (5 mL), extracted with EtOAc (25 mL). The aqueous layer was back extracted with EtOAc (25 mL). The combined organic layers were dried over anhydrous Na2SO4 and concentrated. The crude was further purified by silica gel column chromatography (eluent: 10% EtOAc in petroleum ether) to afford tert-butyl (3-(1H-indol-5-yl)-1,2,4-thiadiazol-5-yl)carbamate (50 mg, 44.2%) as an off white solid. MS (ESI, pos. ion) m/z: 261 (M+1); 1H NMR (400 MHz, DMSO-d6): δ 12.40 (s, 1H), 11.31 (s, 1H), 8.35 (s, 1H), 7.91 (dd, J=1.2 Hz & 8.4 Hz, 1H), 7.46 (d, J=8.4 Hz, 1H), 7.41-7.40 (m, 1H), 6.35 (s, 1H), 1.52 (s, 9H).

Workup

  1. customN2 gas was purged for 15 min
  2. temperaturethe reaction was heated
  3. temperatureat reflux for 4 h
  4. additiontreated with H2O (5 mL)
  5. extractionextracted with EtOAc (25 mL)
  6. extractionThe aqueous layer was back extracted with EtOAc (25 mL)
  7. dry with materialThe combined organic layers were dried over anhydrous Na2SO4
  8. concentrationconcentrated
  9. customThe crude was further purified by silica gel column chromatography (eluent: 10% EtOAc in petroleum ether)

Sources & evidence

ORD record
ord-4930042288cf4bf7aed8ce4f4f2fb1e9
Source dataset
uspto-grants-2016_04
Patent number
US09321756B2

Reaction notes

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