5-Chloro-2-methylbenzoxazole → Benzoxazole

HRID 2197512Notes

Reaction equation

HRID 2197512 reaction equation
Cl[C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8](C)=[N:7][C:6]=2[CH:11]=1.COC1C=CC=C(OC)C=1C1C=CC=CC=1P(C1CCCCC1)C1CCCCC1>CC([O-])=O.CC([O-])=O.[Pd+2]>[O:9]1[C:5]2[CH:4]=[CH:3][CH:2]=[CH:11][C:6]=2[N:7]=[CH:8]1

Participants

4

Reactant 2

HCID 295105-Chloro-2-methylbenzoxazoleHCID 112698722-Dicyclohexylphosphino-2',6'-dimethoxybiphenyl

Product 1

HCID 9228Benzoxazole

Reagents, catalysts & solvents 1

HCID 167845palladium(II) acetateCatalyst

Conditions

Temperature
100 °C

Procedure

To form 5-vinyl-2-methylbenzoxazole (4aa), the general procedure was followed using 5-chloro-2-methylbenzoxazole (3d) (167 mg, 1.01 mmol), vinyl MIDA boronate (2g) (218 mg, 1.19 mmol), SPhos (42 mg, 0.10 mmol) and Pd(OAc)2 (11 mg, 0.050 mmol). The reaction time and temperature were modified so that the reaction mixture was heated to 100° C. for 2 h. Benzoxazole 4aa was isolated as a pale golden liquid (152 mg, 96%). TLC (hexanes:EtOAc 3:1) Rf=0.46, visualized by UV (254 nm). 1H-NMR (500 MHz, CDCl3 w/TMS) δ 7.67 (s, 1H), 7.38 (d, J=8.0 Hz, 1H), 7.34 (d, J=8.0 Hz, 1H), 6.79 (dd, J=17.5, 11.0 Hz, 1H), 5.74 (d, J=17.5 Hz, 1H), 5.24 (d, J=11.0 Hz, 1H), 2.61 (s, 3H). 13C-NMR (125 MHz, CDCl3) δ 164.3, 150.6, 141.9, 136.5, 134.2, 122.9, 116.8, 113.4, 109.9, 14.5. HRMS (El+) Calculated for C10H9NO (M)+: 159.0684, Found: 159.0685. IR (KBr, cm−1) 3087, 3006, 2984, 2928, 1623, 1622, 1578, 1477, 1433, 1381, 1335, 1262, 1179, 1114, 1040, 989, 918, 881, 840, 815.

Sources & evidence

ORD record
ord-cd6b010b32fc46fcaa3de0688632457a
Source dataset
uspto-grants-2012_12
Patent number
US08338601B2

Reaction notes

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