Pyridine → 1,3-benzothiazole-2-carbonitrile
Reaction equation
[S:1]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=[C:2]1[C:10]([NH2:12])=O.N1C=CC=CC=1.O=P(Cl)(Cl)Cl>CCOC(C)=O.CCCCCC>[C:10]([C:2]1[S:1][C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2[N:3]=1)#[N:12]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- 0 °C
Procedure
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).
Workup
- customthe acetone/ice bath was removed
- stirringthe reaction was stirred at RT for 2 h further
- customThe tan/brown-colored reaction
- customwas then transferred to a larger reaction flask
- customThe reaction was quenched by the dropwise addition of water
- washThe organic product 10 was washed with water
- extractionextracted with EtOAc
- concentrationconcentrated in vacuo
- customto yield a light yellow/orange product
Sources & evidence
- ORD record
- ord-227e9043efb04fc1ae84f814bd0e0836
- Source dataset
- uspto-grants-2013_11
- Patent number
- US08586759B2
Reaction notes
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