Ustiloxins AF 是抗有丝分裂杂环肽,含有 13 元环状核心结构,具有合成上具有挑战性的手性叔烷基芳基醚键。使用 S(N)Ar 反应,通过 31 个线性步骤实现了 ustiloxin D 的首次全合成。该合成产品的 NOE 研究表明乌司洛辛 D 作为单一阻转异构体存在。随后,利用新发现的乙炔基氮丙啶开环反应,以 15 个步骤的最长线性序列开发了乌斯蒂洛辛 D 和 F 的高度简洁和收敛的合成方法。该方法进一步优化以实现更好的大环内酰胺化策略。通过第二代制备了乌斯蒂洛辛D、F和8个类似物(14-MeO-乌斯蒂洛辛D、4个C-6位氨基酸残基不同的类似物、以及3个(9R,10S)-表乌斯蒂洛辛类似物)路线。对这些化合物作为微管蛋白聚合抑制剂的评估表明,C-6 位的变化在一定程度上是可以容忍的。相反,C-9 甲氨基的 S 构型和游离酚羟基对于抑制微管蛋白聚合至关重要。
Intermolecular Rhodium(II)-Catalyzed Reactions with Silicon-Substituted Carbonyl Ylides
作者:Carsten Bolm、Sandra Saladin、Andrey Kasyan
DOI:10.1021/ol026987m
日期:2002.12.1
[reaction: see text] The Rh(II)-catalyzed reaction of benzyl 2-trialkylsilyl-2-diazoacetates with various acyclic and cyclic ketones affords novel dioxolanones via silicon-substituted carbonyl ylides in up to 98% yield.
Prostate-specific membrane antigen (PSMA) has been identified as a diagnostic and therapeutic target for prostate cancer. (S)-2-[3-[(R)-1-Carboxy-2-mercaptoethyl]ureido-pentanedioic acid (Cys-CO-Glu) were used to design novel PSMA targeting probes by nucleophilic conjugate addition between cysteine and maleimide based reagents. 3 ([I-123]IGLCE) was synthesized by this strategy and showed high affinity for PSMA. Results of binding inhibition assays of these derivatives suggested the importance of an aromatic group and succinimide moiety for high affinity. [I-123]3 was evaluated in vivo with PSMA positive LNCaP and PSMA negative PC-3 human prostate cancer xenograft bearing mice. [I-125]3 accumulated in LNCaP tumors but not in PC-3 tumors, and the accumulation was inhibited by 2-(phosphonomethyl)pentanedioic acid (2-PMPA). Use of [I-123]3 provided positive images of LNCaP tumors in single photon emission tomography scans. These results warrant further evaluation of [I-123]3 and its derivatives as radiolabeled probes for the diagnosis of prostate cancer.
Maclaren,J.A., Australian Journal of Chemistry, 1971, vol. 24, p. 1695 - 1702