ChemicalBook CAS DataBase List 7-Chlorothieno[3,2-b]pyridine

7-Chlorothieno[3,2-b]pyridine synthesis

11synthesis methods

Product Name:7-Chlorothieno[3,2-b]pyridine
CAS Number:69627-03-8
Molecular formula:C7H4ClNS
Molecular Weight:169.63

69627-02-7

69627-03-8

To a 250 mL round-bottomed flask were added 30 mL of methylene chloride and 20 mL of ethylene chloride, followed by N,N-dimethylformamide (1.8 mL, 23.28 mmol) and oxalyl chloride (2.9 mL, 33.86 mmol). Oxalyl chloride was slowly added dropwise to the mixture at 0 °C. Next, thieno[3,2-b]pyridin-7(4H)-one (1.6 g, 10.58 mmol) was added and the reaction mixture was heated to reflux for 6 hours. After completion of the reaction, the mixture was cooled to room temperature to afford 7-chlorothieno[3,2-b]pyridine (1.7 g, 90% yield) as a pale yellow solid. The product was characterized by 1H-NMR (400 MHz, CDCl3): δ 8.61 (d, J = 5.2 Hz, 1H), 7.81 (d, J = 5.2 Hz, 1H), 7.30 (d, J = 4.8 Hz, 1H).

107818-20-2
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$10.00/250mg

69627-03-8
175 suppliers
$6.00/100mg

Yield:69627-03-8 96%

Reaction Conditions:

Stage #1: thieno[3,2-b]pyridin-7-olwith trichlorophosphate at 60 - 100; for 3.5 h;
Stage #2: with ammonia;water monomer at 0;

Steps:

1

7-Chlorothieno[3,2-6]pyridine (6); To neat POCl₃ (200 mL, 2146 mmol) at 6O⁰C in a 500 mL round-bottom flask was added thieno[3,2-&]pyridin-7-ol (1 eq., 200 g, 1323 mmol) in small portions over 1.5 h. The reaction mixture was heated at 6O⁰C for Ih and at 100⁰C for an additional hour. After cooling down to O⁰C, the reaction mixture was poured onto crushed ice (1 L) over a period of 30 min. After 15 min, NH₄OH (1.5 L) was added to the mixture to form a grey precipitate that was collected by filtration, washed with water (50 mL) and air dried. The dry solid was suspended in EtOAc (1 L). The slurry was stirred at r.t. for 15 min, filtered and the filter was washed with EA (2x 100 mL). The organic phase was collected, dried over MgSO₄ and concentrated. The residue was passed through a short silica gel pad (300 g, eluent - a gradient hexane/EtOAc, 8/2 to 5/5) and dried in the vacuum oven (35⁰C) for 2h to afford 6 as a off-white solid (214.8 g, 1266 mmol, 96% yield). MS (m/z): 170.0 (M+H). ¹H NMR (400 MHz, DMSO-d₆) δ (ppm): 8.64 (d, J = 5.1 Hz, IH), 8.25 (d, J = 5.5 Hz, IH), 7.66 (d, J = 5.5 Hz, IH), 7.54 (d, J = 5.1 Hz, IH).