Aminopyrazine → N-(pyrazin-2-yl)-4-(2-(1,2,3,6-tetrahydropyridin-4-yl)-4-(trifluoromethyl)phenyl)-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-sulfonamide

HRID 528562Notes

Reaction equation

HRID 528562 reaction equation
FC1C(F)=C(F)C(F)=C(F)C=1[O:4][S:5]([C:8]1[CH:9]=[CH:10][C:11]2[N:16]([C:17]3[CH:22]=[CH:21][C:20]([C:23]([F:26])([F:25])[F:24])=[CH:19][C:18]=3[C:27]3[CH2:32][CH2:31][N:30](C(OC(C)(C)C)=O)[CH2:29][CH:28]=3)[CH2:15][CH2:14][O:13][C:12]=2[CH:40]=1)(=O)=[O:6].[N:49]1[CH:54]=[CH:53][N:52]=[CH:51][C:50]=1[NH2:55].C[Si]([N-][Si](C)(C)C)(C)C.[Li+]>C(O)(C(F)(F)F)=O.C1COCC1>[N:49]1[CH:54]=[CH:53][N:52]=[CH:51][C:50]=1[NH:55][S:5]([C:8]1[CH:9]=[CH:10][C:11]2[N:16]([C:17]3[CH:22]=[CH:21][C:20]([C:23]([F:24])([F:26])[F:25])=[CH:19][C:18]=3[C:27]3[CH2:32][CH2:31][NH:30][CH2:29][CH:28]=3)[CH2:15][CH2:14][O:13][C:12]=2[CH:40]=1)(=[O:6])=[O:4]

Participants

6

Reactant 3

HCID 78747AminopyrazineHCID 2733832Lithium HexamethyldisilazideHCID 89761263tert-butyl 4-(2-(7-((perfluorophenoxy)sulfonyl)-2H-benzo[b][1,4]oxazin-4(3H)-yl)-5-(trifluoromethyl)phenyl)-5,6-dihydropyridine-1(2H)-carboxylate

Product 1

HCID 71711366N-(pyrazin-2-yl)-4-(2-(1,2,3,6-tetrahydropyridin-4-yl)-4-(trifluoromethyl)phenyl)-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-sulfonamideYield 49.1%

Reagents, catalysts & solvents 2

HCID 6422Trifluoroacetic acidCatalystHCID 8028TetrahydrofuranSolvent

Procedure

A round-bottom flask was charged with tert-butyl 4-(2-(7-((perfluorophenoxy)sulfonyl)-2H-benzo[b][1,4]oxazin-4(3H)-yl)-5-(trifluoromethyl)phenyl)-5,6-dihydropyridine-1(2H)-carboxylate (INTERMEDIATE AA, 37.7 mg, 0.053 mmol), pyrazin-2-amine (7.61 mg, 0.080 mmol, TCI America, Portland, Oreg.), and THF (1 mL) to give a clear, colorless solution. The flask was cooled in a dry ice-acetone bath for 5 min, then lithium bis(trimethylsilyl)amide (1M in THF) (112 μL, 0.112 mmol) was added dropwise over 30 s to give a light-yellow solution. After 20 min, the flask was lowered into an ice bath. After another 30 min, TFA (3 drops) was added via syringe, and the mixture was concentrated. The residue was dissolved in DCM (1 mL) and TFA (0.5 mL). After 20 min, the mixture was concentrated, and the residue was dissolved in MeOH and loaded onto a 500 mg SCX-2 ion exchange column. The column was eluted with MeOH then with 2N ammonia in methanol. The basic fraction was concentrated. The residue was further purified by chromatography on silica gel (12 g column, 10% MeOH/DCM, then 20% of a 2N ammonia in methanol solution dissolved in DCM) to give N-(pyrazin-2-yl)-4-(2-(1,2,3,6-tetrahydropyridin-4-yl)-4-(trifluoromethyl)phenyl)-3,4-dihydro-2H-benzo[b][1,4]oxazine-7-sulfonamide (13.49 mg, 0.026 mmol) as an off-white solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 8.08 (s, 1 H), 8.02 (s, 1 H), 7.86 (br. s., 1 H), 7.72 (dd, J=1.7, 8.6 Hz, 2 H), 7.59 (d, J=1.9 Hz, 1 H), 7.54 (d, J=8.1 Hz, 1 H), 6.43 (d, J=8.5 Hz, 1 H), 5.87 (br. s., 1 H), 4.27 (br. s., 2 H), 3.61-3.53 (m, J=6.1 Hz, 5 H), 3.09 (br. s., 2 H), 2.39-2.30 (m, 1 H). m/z (ESI) 518.4 (M+H)+.

Workup

  1. customto give a clear, colorless solution
  2. temperatureThe flask was cooled in a dry ice-acetone bath for 5 min
  3. customto give a light-yellow solution
  4. customthe flask was lowered into an ice bath
  5. waitAfter another 30 min
  6. concentrationthe mixture was concentrated
  7. dissolutionThe residue was dissolved in DCM (1 mL)
  8. waitAfter 20 min
  9. concentrationthe mixture was concentrated
  10. dissolutionthe residue was dissolved in MeOH
  11. washThe column was eluted with MeOH
  12. concentrationThe basic fraction was concentrated
  13. customThe residue was further purified by chromatography on silica gel (12 g column, 10% MeOH/DCM
  14. dissolution20% of a 2N ammonia in methanol solution dissolved in DCM)

Sources & evidence

ORD record
ord-47284b7a92be4d638d43e900f0c9a870
Source dataset
uspto-grants-2016_05
Patent number
US09346798B2

Reaction notes

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