An Efficient Solid-phase Parallel Synthesis of 2-Amino and 2-Amidobenzo[d]oxazole Derivatives via Cyclization Reactions of 2-Hydroxyphenylthiourea Resin
作者:Se-Lin Jung、Seul-Gi Kim、Gee-Hyung Lee、Young-Dae Gong
DOI:10.5012/bkcs.2012.33.12.4109
日期:2012.12.20
An efficient solid-phase methodology has been developed for the synthesis of 2-amino and 2-amidobenzo[d]-oxazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo-[d]oxazole resins 4 by cyclization reaction of 2-hydroxy-phenylthiourea resin 3. The resin-bound 2-hydroxyphenylthiourea 3 is produced by the addition of 2-aminophenol to the isothiocyanate-terminated resin 2 and serve as a key intermediate for the linker resin. This core skeleton 2-aminobenzo[d]oxazole resin 4 undergoes functionalization reaction with various electrophiles, such as alkylhalides and acid chlorides to generate 2-amino and 2-amidobenzo[d]oxazole resins 5 and 6 respectively. Finally, 2-amino and 2-amidobenzo[d]oxazole derivatives 7 and 8 are then generated in good yields and purities by cleavage of the respective resins 5 and 6 under trifluoroacetic acid (TFA) in dichloromethane ($CH_2Cl_2$).
开发了一种高效的固相合成方法,用于合成2-氨基和2-酰胺基苯并[d]噁唑衍生物。该方法的关键步骤是通过2-羟基苯硫脲树脂3的环化反应制备聚合物结合的2-氨基苯并[d]噁唑树脂4。树脂结合的2-羟基苯硫脲3是通过将2-氨基酚加到异硫氰酸酯终端树脂2上制备的,并作为接头树脂的关键中间体。这个核心骨架2-氨基苯并[d]噁唑树脂4通过与各种亲电试剂(如烷基卤化物和酰氯)进行功能化反应,分别生成2-氨基和2-酰胺基苯并[d]噁唑树脂5和6。最后,通过在二氯甲烷中使用三氟乙酸(TFA)切割相应的树脂5和6,可以高产率和纯度地得到2-氨基和2-酰胺基苯并[d]噁唑衍生物7和8。