[N-]=[N+]=[N-].[N:4]([C:7]1([CH3:18])[C:16]2[C:11](=[CH:12][CH:13]=[C:14]([I:17])[CH:15]=2)[O:10][CH2:9][CH2:8]1)=[N+]=[N-].CP(C)C.O>C1COCC1>[I:17][C:14]1[CH:15]=[C:16]2[C:11](=[CH:12][CH:13]=1)[O:10][CH2:9][CH2:8][C:7]2([CH3:18])[NH2:4]To a mixture of 6-iodo-4-methylchroman-4-ol (1.0 g, 3.4 mmol) and NaN3 (0.7 g, 10.3 mmol) in CHCl3 (15 ml), at 0° C., was added TFA (1.3 ml, 17.2 mmol) as a solution in 10 ml of CHCl3 dropwise via addition funnel. The addition was carried out over 2 h and stirring continued for an additional 2 h at 0° C. The mixture was warmed to r.t. and stirred over night. The mixture was diluted with 30 ml of water and extracted with CH2Cl2. The organic layer was dried over Na2SO4 and concentrated in vacuo to yield 4-azido-6-iodo-4-methylchroman as a yellow oil. 1H NMR (400 MHz, CDCl3) δ 7.65 (d, J=2.07 Hz, 1H), 7.50 (dd, J=8.71, 2.07 Hz, 1H), 6.66 (d, J=8.71 Hz, 1H), 4.27 (m, 2H), 2.06 (m, 2H), 1.68 (s, 3H). MS (ESI+) for C10H10IN3O m/z 273.0 (M+H)+ loss of azide. The crude azide was dissolved in THF (15 ml) followed by the addition of trimethylphosphine (4 ml, 1.0 M in THF) at r.t. After 15 min. 3 ml of water was added and stirring continued at r.t. for 2 h until complete as indicated by LC/MS. The solvent was removed in vacuo and the residue diluted with water (75 ml) and extracted with CH2Cl2 (3×50 ml). The organic layer was dried over Na2SO4 and concentrated in vacou to yield 6-iodo-4-methylchroman-4-amine (0.900 g, 91%) as a yellow oil. This material was used in the next step without purification. 1H NMR (400 MHz, CDCl3) δ 7.77 (d, J=2.07 Hz, 1H), 7.40 (dd, J=8.60, 2.18 Hz, 1H), 6.59 (d, J=8.50 Hz, 1H), 4.25 (m, 2H), 2.01 (m, 2H), 1.53 (s, 3H). MS (ESI+) for C10H12INO m/z 273.2 (M+H)+ loss of NH3.
Wird geladen…
