Ethyl 6-chloronicotinate → Ethyl 6-[(2,2,4,4-tetramethylchroman-6-yl)-ethynyl]nicotinate

HRID 1493791Notes

Reaction equation

[CH3:1][C:2]1([CH3:16])[CH2:11][C:10]([CH3:13])([CH3:12])[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:14]#[CH:15])[CH:8]=2)[O:3]1.Cl[C:18]1[CH:28]=[CH:27][C:21]([C:22]([O:24][CH2:25][CH3:26])=[O:23])=[CH:20][N:19]=1>C(N(CC)CC)C.[Pd](Cl)Cl.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>[CH3:1][C:2]1([CH3:16])[CH2:11][C:10]([CH3:12])([CH3:13])[C:9]2[C:4](=[CH:5][CH:6]=[C:7]([C:14]#[C:15][C:18]3[CH:28]=[CH:27][C:21]([C:22]([O:24][CH2:25][CH3:26])=[O:23])=[CH:20][N:19]=3)[CH:8]=2)[O:3]1

Participants

Conditions

Temperature: 55 °C

Procedure

A solution of 233 mg (1.09 mmol) of 2,2,4,4-tetramethyl-6-ethynylchroman (Compound 5) and 209 mg (1.09 mmol) of ethyl 6-chloronicotinate (Compound 9s) in 1 ml of triethylamine was degassed and then treated under argon with a powdered mixture of 50 mg (0.26 mmol) of cuprous iodide and 100 mg (0.14 mmol) of bis(triphenylphosphine) palladium (II) chloride. The reaction mixture was heated under argon at 55 degrees C. for 80 h and then cooled to room temperature. The triethylamine was then removed under vacuum and the residue purified by lash chromatography (silica; 5% ethyl acetate in hexanes) to give the title compound as a yellow oil. PMR (CDCl3): & 1.36 (12H, s), 1.42 (3H, t, J~7.2 Hz), 1.85 (2H, s), 4.37 (2H, q, J~7.2 Hz), 6.79 (1H, d, J~4 Hz), 7.34 (1H, dd, J~8.4 Hz, 2.1 Hz), 7.56 (1H, d, J~8.7 Hz), 7.60 (1H, d, J~2.1 Hz), 8.27 (1H, dd, J~8.7 Hz, 2.4 Hz), 9.19 (1H, d, J~2.4 Hz). MS exact mass, m/e 363.1837 (calcd. for C23H25O3N, 363 1834).

Workup

temperaturecooled to room temperature
customThe triethylamine was then removed under vacuum
customthe residue purified by lash chromatography (silica; 5% ethyl acetate in hexanes)

Sources & evidence

ORD record: ord-472b39675d3740b6bb73b11ab77a2c22
Source dataset: uspto-grants-1991_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05023341

Reaction notes

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