Pyridine → 1,3-benzothiazole-2-carbonitrile

Participants

Reaction Conditions

Reaction Steps

Benzothiazole-2-carboxamide 8 (0.61 mmol, 0.1 g) was dissolved in anhydrous pyridine (0.080 mol, 6.5 ml) and stirred under N2 at 0° C. The temperature of the reaction was dropped to 0° C. during dropwise addition of POCl3 (0.015 mol, 1.4 ml). The solution immediately changed from clear to a pale pink coloring with addition of POCl3. After 20 min, the acetone/ice bath was removed and the reaction was stirred at RT for 2 h further. The tan/brown-colored reaction was then transferred to a larger reaction flask containing 10 ml EtOAc at 0° C. The reaction was quenched by the dropwise addition of water. The organic product 10 was washed with water, extracted with EtOAc, and concentrated in vacuo to yield a light yellow/orange product. TLC analysis (3 Hexane: 2 EtOAc) and Agilent HPLC displayed 100% conversion to the desired product (single peak at 10.5 min). The compound was used in the subsequent step without purification (95% yield). ESI-MS: m/z calcd for C8H4N2S 161.01 (M+H)+, 160.86 found (100%). (see LC/MS spectra of FIG. 19A and NMR spectra of FIG. 19B).

Provenance & Evidence