(Dimethyl sulfide)trihydroboron → 2,3-Dihydro-1H-pyrido[3,4-b][1,4]oxazine
Reaction equation
[NH:1]1[C:6](=O)[CH2:5][O:4][C:3]2[CH:8]=[N:9][CH:10]=[CH:11][C:2]1=2.B.CSC>O1CCCC1>[NH:1]1[CH2:6][CH2:5][O:4][C:3]2[CH:8]=[N:9][CH:10]=[CH:11][C:2]1=2Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 25 °C
Procedure
To a stirred solution of 1H-pyrido-[3,4-b][1,4]oxazine-2-(3H)one (3 g, 21 mmol) in tetrahydrofuran (150 ml) was added rapidly a borane/dimethyl sulfide solution (52 ml of a 2M solution in THF, 5 eq) at 25° C. over 15 minutes. The reaction mixture was stirred at 25° C. for 2 hours and quenched with 5 ml of water. The solvent was removed in vacuo using a rotary evaporator and the residue treated with aqueous 1M HCl with stirring. The water was removed and the residue chromatographed on silica gel using CH2Cl2 /MeOH/NH4OH (90/10/1) to give 2 g (70%) of titled product. m.p. 167°-169° C. The structural assignment is supported by the proton NMR spectrum.
Workup
- customquenched with 5 ml of water
- customThe solvent was removed in vacuo
- customa rotary evaporator
- additionthe residue treated with aqueous 1M HCl
- stirringwith stirring
- customThe water was removed
- customthe residue chromatographed on silica gel
Sources & evidence
- ORD record
- ord-a0108b003d4f4800933b37f2cf7a7115
- Source dataset
- uspto-grants-1997_07
- Patent number
- US05652363
Reaction notes
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