Efficient Arndt–Eistert Synthesis of Selective 5-HT₇ Receptor Antagonist SB-269970

Synthesis, Radiolabeling, and in Vitro and in Vivo Evaluation of [18F]ENL30: A Potential PET Radiotracer for the 5-HT7 Receptor

“…This strategy was initially thought to be inferior since an unnecessary deprotection/protection had to be applied. However, this approach yielded in sufficient amounts of ( 10 ) that could be used in a subsequent coupling step with another key intermediate 3-(2-fluoroethoxy)­benzenesulfonyl chloride ( 14 ). ,,, The synthesis of ( 14 ) is detailed in Scheme . Notably, in the final step in the synthesis of 14 , the need for S -deprotection was circumvented and allowed direct oxidation of sulfur. , In summary, the reference synthesis was completed in 13 steps, ending up with an overall low yield of approximately 0.2%.…”

“…However, this approach yielded in sufficient amounts of (10) that could be used in a subsequent coupling step with another key intermediate 3-(2-fluoroethoxy)benzenesulfonyl chloride (14). 31,35,36,38 The synthesis of ( 14) is detailed in Scheme 1. Notably, in the final step in the synthesis of 14, the need for Sdeprotection was circumvented and allowed direct oxidation of sulfur.…”

Unusual Chemoselective RhII‐Catalysed Transformations of α‐Diazocarbonyl Piperidine Cores

“…The procedure of Schjøth-Eskesen et al was adopted to obtain the diazocarbonyl compounds. [14] It consists of the transformation of a carboxylic acid into a mixed anhydride, which is then treated with diazomethane. In general, due to their instability, the anhydrides were prepared and immediately used for the preparation of diazoketone derivatives 13-15 (Scheme 3).…”

“…The procedure of Schjøth‐Eskesen et al. was adopted to obtain the diazocarbonyl compounds 14. It consists of the transformation of a carboxylic acid into a mixed anhydride, which is then treated with diazomethane.…”