(S)-(+)-2-ФТОР-АЛЬФА-МЕТИЛ-4-ДИФЕНИЛУКСУСНАЯ КИСЛОТА

Описание

(S)-Flurbiprofen is the COX-active enantiomer of the non-selective COX inhibitor flurbiprofen with IC₅₀ values of 0.48 and 0.47 μM for COX-1 and COX-2, respectively, in guinea pig whole blood. It inhibits the release of 6-keto prostaglandin F_1α (6-keto-PGF_1α; ) and thromboxane B₂ (TXB₂; ) from rat whole blood, gastric mucosa, lung, and jejunal tissue ex vivo in a dose-dependent manner. (S)-Flurbiprofen (1 nM) inhibits basal and bradykinin-, serotonin-, and histamine-stimulated prostaglandin E₂ (PGE₂) release from isolated skin flaps of rat lower hind paws. It also inhibits release of the neuroinflammatory marker calcitonin gene-related peptide (CGRP; Item Nos. 24405 | 24725 | 24728) when used at a concentration of 1 μM. In vivo, (S)-flurbiprofen reduces the number of flinches per minute in the formalin test in rats, indicating antinociceptive activity.

Использование

(S)-Flurbiprofen is the S-isomer of Flurbiprofen (F598700), an anti-inflammatory used as an analgesic.

Синтез

The synthesis began with conversion of commercially available aniline 168 to racemic flurbiprofen (169) through a Sandmeyer reaction and subsequent phenyl group introduction through the use of sodium tetraphenylborate. A chiral resolution was then performed on the resulting stereogenic acid on multikilogram scale by treatment with (S)- 1-phenylethylamine in MeOH/toluene, which gave various yields of salt 170 as reported by the authors. Acidification with aqueous HCl delivered (S)-flurbiprofen (XXI). Importantly, with respect to green chemistry considerations, the (R)- enantiomer could be recycled by racemizing the undesired (R)- enantiomer 171 in refluxing methanolic sulfuric acid, improving the overall atom economy of the process and significantly reducing waste.