Hamri, Salha; Jouha, Jabrane; Oumessaoud, Asmaa; Pujol, M. D.; Khouili, Mostafa; Guillaumet, Gerald published their research in Tetrahedron in 2021. The article was titled 《Convenient approach for the synthesis of ONO-LB-457, a potent leukotriene B4 receptor antagonist》.Name: Ethyl 5-bromovalerate The article contains the following contents:
This study reported a new approach for the synthesis of 5-[2-(2-carboxyethyl)-3-[(E)-6-(4-methoxyphenyl)hex-5-enoxy]phenoxy]pentanoic acid I (ONO-LB-457), which was considered a highly potent and orally active LTB4 receptor antagonist. In this work, the preparation of compound I was proposed through a convergent synthesis focused on the preparation of two fragments. First, the preparation of 5-hydroxychroman-2-one from 2,6-dimethoxybenzaldehyde and malonic acid, involving a Knoevenagel reaction, followed by a reduction of the olefin and intramol. cyclization catalyzed by Lewis acid (tribromide) was achieved with an overall yield of 57%. Second, preparation of [(E)-6-(4-methoxyphenyl)hex-5-enyl] methanesulfonate from 5-bromovaleric acid involved a Wittig reaction. The desired compound I was obtained by nucleophilic substitution of [(E)-6-(4-methoxyphenyl)hex-5-enyl] methanesulfonate with Et 5-[2-(3-ethoxy-3-oxo-propyl)-3-hydroxy-phenoxy]pentanoate followed by hydrolysis, in seven steps with an overall yield of about 11%. In the experiment, the researchers used Ethyl 5-bromovalerate(cas: 14660-52-7Name: Ethyl 5-bromovalerate)
Ethyl 5-bromovalerate(cas: 14660-52-7) belongs to bromides. Most organobromine compounds, like most organohalide compounds, are relatively nonpolar. Bromine is more electronegative than carbon (2.9 vs 2.5). Consequently, the carbon in a carbon–bromine bond is electrophilic, i.e. alkyl bromides are alkylating agents.Name: Ethyl 5-bromovalerate
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary