Nitrogen → 4-Allyl-7-methyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydro-2H-benzo[b][1,4]oxazine

HRID 1400706Notes

Reaction equation

HRID 1400706 reaction equation
[CH3:1][C:2]1[C:3]([B:12]2[O:16][C:15]([CH3:18])([CH3:17])[C:14]([CH3:20])([CH3:19])[O:13]2)=[CH:4][C:5]2[NH:10][CH2:9][CH2:8][O:7][C:6]=2[CH:11]=1.C([O-])([O-])=O.[K+].[K+].N#N.[CH2:29](Br)[CH:30]=[CH2:31]>CN(C=O)C.O>[CH2:31]([N:10]1[CH2:9][CH2:8][O:7][C:6]2[CH:11]=[C:2]([CH3:1])[C:3]([B:12]3[O:13][C:14]([CH3:20])([CH3:19])[C:15]([CH3:18])([CH3:17])[O:16]3)=[CH:4][C:5]1=2)[CH:30]=[CH2:29]

Participants

7

Reactant 4

HCID 947NitrogenHCID 7841Allyl bromideHCID 11430Potassium CarbonateHCID 867107587-methyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydro-2H-benzo[b][1,4]oxazine

Product 1

HCID 867107574-Allyl-7-methyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydro-2H-benzo[b][1,4]oxazineYield 52.9%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6228DimethylformamideSolvent

Conditions

Temperature
70 °C

Procedure

A solution of 7-methyl-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydro-2H-benzo[b][1,4]oxazine (0.488 g, 1.774 mmol, prepared according to the procedures outlined for related compounds in Ref. WO20100130034) and K2CO3 (0.490 g, 3.55 mmol) in dry DMF (5 mL) was sparged with N2 for 5 min, treated with allyl bromide (0.773 mL, 8.87 mmol), then heated (70° C.) for 22 h. The reaction was diluted with water (50 mL) and extracted into EtOAc (50 mL) and washed with water, brine and then dried (Na2SO4), filtered, and concentrated. The crude was purified by biotage column chromatography (12 g SiO2, 0% (3 CV), 0-40% (10 CV), 40% (2 CV), EtOAc in hexanes). Product rich fractions were re-purified by biotage (0% (3 CV), 0-40% (15 CV), 40% (2 CV), EtOAc in hexanes) to afford the desired product (0.345 g, 0.938 mmol, 52.9% yield), as a colorless viscous oil. 1H NMR (500 MHz, CDCl3) δ 7.20 (s, 1H), 6.62 (d, J=0.5 Hz, 1H), 5.92 (ddt, J=16.9, 10.4, 5.9 Hz, 1H), 5.29 (dq, J=17.2, 1.6 Hz, 1H), 5.23 (dq, J=10.2, 1.4 Hz, 1H), 4.30-4.24 (m, 2H), 3.89 (dt, J=5.9, 1.3 Hz, 2H), 3.27-3.18 (m, 2H), 2.43 (s, 3H), 1.33 (s, 12H).

Workup

  1. extractionextracted into EtOAc (50 mL)
  2. washwashed with water, brine
  3. dry with materialdried (Na2SO4)
  4. filtrationfiltered
  5. concentrationconcentrated
  6. customThe crude was purified by biotage column chromatography (12 g SiO2, 0% (3 CV), 0-40% (10 CV), 40% (2 CV), EtOAc in hexanes)
  7. customProduct rich fractions were re-purified by biotage (0% (3 CV), 0-40% (15 CV), 40% (2 CV), EtOAc in hexanes)

Sources & evidence

ORD record
ord-d2affa5bd222447fa7b34b40f86c6ac0
Source dataset
uspto-grants-2014_12
Patent number
US08906929B2

Reaction notes

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