Synthesis of the C11–C23 Fragment of the Potent Antitumor Agent Dictyostatin

Abstract

Descrevemos neste trabalho uma síntese curta e eficiente para o fragmento C1-C9 do potente agente antitumoral dictiostatina. Esta abordagem sintética inclui uma reação de epoxidação assimétrica de Sharpless seguida da abertura de epóxido nas condições de Myashita para introduzir os centros estereogênicos em C6 e C7 e uma reação de olefinação tipo Horner-Wadsworth-Emmons nas condições de Ando para construir a ligação com geometria /Z/do dieno 1,3-/Z/,/E/.We describe herein a short and efficient synthesis of the C1-C9 fragment of the potent antitumor agent dictyostatin. Notable features of this approach include a Sharpless asymmetric epoxidation followed by epoxide opening under Myashita's conditions to introduce the stereogenic centers at C6 and C7, and a Horner-Wadsworth-Emmons type reaction under Ando's conditions to construct the Z-double bond of the 1,3-(Z,E)-diene system.

Growth of Hydrophilic CuS Nanowires via DNA‐Mediated Self‐Assembly Process and Their Use in Fabricating Smart Hybrid Films for Adjustable Chemical Release

“…R f = 0.36 (20 % EtOAc in hexane). [ α ] D 20 = +8.0 ( c = 1.02, CHCl 3 ) 24 . 1 H NMR (250 MHz, C 6 D 6 ): δ = 0.10 (s, 3 H), 0.14 (s, 3 H), 1.02 (s, 9 H), 1.18 (d, J = 7.0 Hz, 3 H), 1.34 (d, J = 7.0 Hz, 3 H), 2.27–2.18 (m, 1 H), 2.86 (s, 3 H), 3.08 (br.…”

Synthesis, electrochemical studies and anticancer activity of ferrocenyl oxindoles

“…The cells were thereafter washed twice with phosphate buffered saline (PBS) to remove detached cells. Growth media was then added containing different concentrations of the chemical compound and incubated at 37 • C. 28 The cells were photographed at the beginning of the experiment and after 24 and 48 h to assess the progression of cell migration into the wound. 29,30 Chamber cell-migration assay.…”

“…In addition, it is important to note that the ferrocenyl oxindoles studied are structurally simple and easily accessible, therefore representing new potential lead compounds for further development in cancer therapy. 27,28 Experimental IR spectra were recorded on a Nicolet Magna 760 (KBr). 1 H-and 13 C-NMR were recorded on Bruker 250 or 500 MHz spectrometers.…”

1H chemical shift differences of Prelog–Djerassi lactone derivatives: DFT and NMR conformational studies

“…Lactone 2 used in the NMR studies was an authentic sample synthesised according to the method described in ref. 7. Data of 2: R f 0.12 (15% EtOAc-hexane); [α] 20 D = −60 (c = 1.6, CHCl 3 ); for 1 H and 13 C NMR spectra see Table 1.…”

“…6 As part of similar synthetic efforts, the Dias group disclosed the synthesis of the C11-C23 fragment of dictyostatin employing the 3-epi-Prelog-Djerassi lactone derivative (2) as a key intermediate. 7 It was observed that the H-5 methylene of compound 2 presented an anomalous 1 H chemical shift difference (1.02 and 2.54 ppm, Δδ = 1.52 ppm). In general, the chemical shifts of diastereotopic H-5 protons for the Prelog-Djerassi lactone (1) and its derivatives are in the range of 1.2 to 2.0 ppm (Δδ = 0.8 ppm).…”