Synthesis
Preparation of (4-chloro-2-fluorophenyl)methanol:
To a solution of 4-chloro-2-fluorobenzoic acid (300 mg) in THF (15 ml) was added, at 0 C, LiAlH4
(130 mg). The suspension was stirred at 0C for 16 hours. The reaction mixture was diluted using EA and an aqueous solution of potassium sodium tartrate and was added to the solution at .
room temperature for 1 hour. The layers were separated and the organic phase was further washed with water. The combined organic layers were dried over MgSO4, filtered and evaporated in vacuo. The organic phase was extracted by CC (Bchi ).
Sepacore, 5 g column, solvent A: DCM, solvent B: 3N ammonia in MeOH, gradient
(expressed as B%): 0 to 5, flow rate: 6.0 ml/min) purified the crude product to provide 224 mg of colorless oily material. lC-MS(A) tR
= 0.68 min; [M+H]+: not seen.
Preparation of 4-chloro-2-fluorobenzaldehyde:
To a solution of (4-chloro-2-fluorophenyl)methanol (222 mg) in MeCN (20 ml) was added MnO2 (480 mg).
The mixture was stirred for 24 hours. The mixture was filtered through diatomaceous earth, the organic layer was dried through MgSO4 and evaporated in vacuo. The crude aldehyde was used in the next step without purification. lc-ms (A): tR = 0.76 min; [M+H]+: not seen.
