Reactions SRN1 en serie heterocyclique: IV: Reactivite des sels du dimethyl-2,2 nitro-5 dioxanne-1,3
作者:Michel P Crozet、Gaëlle Archaimbault、Patrice Vanelle、Robert Nouguier
DOI:10.1016/s0040-4039(00)98882-8
日期:1985.1
2-Alkyl 2-nitro 1,3-propanediol, 2-alkylidene 1,3-propanediol and 2-dialkylidene 1,3-propanediol are prepared via SRN1 reactions with salts of 2,2-dimethyl 5-nitro 1,3-dioxane and acid-catalyzed cleavage of the resulting acetals.
Lipase-Catalyzed Desymmetrization of Quaternary Carbon-Containing 1,3-Propanediols: A New Entry to the Asymmetric Synthesis of α-Substituted Serine Analogues
作者:Guo-Qiang Lin、Ping Tian、Ming-Hua Xu、Zhi-Qian Wang、Zu-Yi Li
DOI:10.1055/s-2006-939713
日期:——
A new approach to the asymmetric synthesis of α-substituted serine analogues was developed. The method utilizes a lipase-catalyzed esterification desymmetrization protocol. In the presence of PPL, a series of benzyl-substituted quaternary 2-nitropropane-1,3-diols were successfully desymmetrized by selective acetylation in very good yields and enantioselectivities (up to 95% ee).
5-Nitro-1,3-dioxane and 5-nitrohexahydropyrimidine salts are found to be suitable nucleophiles for S(RN)1 reactions. From C-alkylation products, base-promoted nitrous acid elimination and acid-catalyzed cleavage of the resulting acetals afford new compounds. Only the imidazole derivatives exhibit significant amoebicide and trichomonacide activities. Structure-activity relationships are discussed.