反应详情

Two other S-protected p-thiobenzaldehydes were obtained as shown in Scheme 2 (FIG. 15). The thiocyanato-benzaldehyde 8 was prepared according to a general procedure (Suzuki and Abe (1996) Synth. Commun., 26: 3413-3419) in 20% yield. All attempts to improve the yield by replacement of DMF with 1,3-dimethyl-2-imidazolidinone, increasing the temperature, or prolonging the reaction time were unsuccessful. S-Acetylthiobenzaldehyde 9 was prepared in a two-step one-flask procedure. Cleavage of the methyl group of 4-methylthiobenzaldehyde according to a general procedure (Tiecco et al. (1982) Synthesis, 478-480) followed by trapping of the resulting anion with acetyl chloride afforded the desired S-acetylthiobenzaldehyde 9 in 55% yield.

1. temperatureincreasing the temperature
2. customS-Acetylthiobenzaldehyde 9 was prepared in a two-step one-flask procedure