91511-83-0Relevant articles and documents
Chemoenzymatic Formal Total Synthesis of Pancratistatin from Narciclasine-Type Compounds via Myers Transposition: Model Study for a Short Conversion of Narciclasine to Pancratistatin
Lapinskaite, Ringaile,Ghavre, Mukund,Rintelmann, Chelsea L.,Bedard, Korey,Dela Paz, Helen E.,Hudlicky, Tomas
supporting information, p. 2896 - 2900 (2017/10/06)
A formal total synthesis of pancratistatin was accomplished by conversion of advanced intermediates, used in the synthesis of narciclasine, to pancratistatin precursors via Myers' reductive transposition as the key strategic step. The synthesis began with the whole cell fermentation of m -dibromobenzene with JM109(pDTG601a), a recombinant strain that over-expresses toluene dioxygenase, which provided the corresponding cis -dihydrodiol 16 as a single isomer with complete optical purity. The key reductive transposition of the allylic alcohol 8a to olefin 9a allowed for further installation of the C-1/C-2 trans -diol, required for the pancratistatin scaffold, through the introduction of a cyclic sulfate and its subsequent opening. The formal synthesis of pancratistatin was accomplished in 14 steps (12 operations) from commercially available m -dibromobenzene. Experimental and spectral data are provided for all new compounds.
Suzuki-Miyaura coupling of halophenols and phenol boronic acids: Systematic investigation of positional isomer effects and conclusions for the synthesis of phytoalexins from pyrinae
Schmidt, Bernd,Riemer, Martin
, p. 4104 - 4118 (2014/05/20)
The Suzuki-Miyaura couplings of o-, m-, and p-halophenols with o-, m-, and p-phenol boronic acids were investigated for all combinations under standardized conditions, using Pd/C as a heterogeneous catalyst and water as a solvent. In the case of iodophenols, conventional heating was used, while for bromophenols significantly better results could be obtained using microwave irradiation. This systematic study revealed that 2,4′-biphenol is particularly difficult to access, irrespective of the starting materials used, but that these difficulties can be overcome by using different additives. The conclusions drawn from this investigation allowed us to identify conditions for the protecting group-free or minimized total synthesis of biaryl-type phytoalexins. These compounds possess antibacterial activity and are produced by fruit trees as a response to microbial infection.
Application of the β-azidonation reaction to the synthesis of the antitumor alkaloid (+)-pancratistatin
Magnus, Philip,Sebhat, Iyassu K.
, p. 15509 - 15524 (2007/10/03)
o-Vanillin 21 was converted into 24 following literature procedures. Treatment of 24 with n-BuLi/THF followed by addition of 25 gave 26. Dehydration (POCL3/pyridine/DBU), hydrogenation and hydrolysis of 26 gave the ketone 29. Chirality was introduced by deprotonation of 29 with the lithium salt of (+)-bis(αmethylbenzyl)amine, followed by triisopropylsilyl trifluoromethanesulfonate to give 30 (95%). β-Azidonation of 30 with (PhiO)n/TMSN3 rapidly produced 31 (95%) as a mixture of trans- and cis- diastereomers in a 3.5:1 ratio. Reduction with LiAIH4 followed by methyl chloroformate/pyridine gave 32, which on treatment with MCPBA/CH2CL2/imidazole resulted in 33. Hydrolysis of 33 gave 34, which when exposed to KOBu(t)/HMPA at 90 °C resulted in 39. After conversion of 39 into enone 42, epoxidation with NaHCO3/H2O2/MeOH gave 43. Reduction of 43 with L-selectride followed by solvolysis with sodium benzoate in water gave 46, which was immediately acetylated to give 47. Lactam formation (Tf2O/DMAP) converted 47 into 48 and the regioisomer 49 (7:1). The mixture of 48 and 49 demethylated to give 50 and the acetate protecting groups removed to give (+)pancratistatin 1.
FIRST SYNTHESIS OF COTARNONE. THE KEY INTERMEDIATE FOR THE SYNTHESIS OF COTARNINE
Shirasaka, Tadashi,Takuma, Yuki,Imaki, Naoshi
, p. 1223 - 1232 (2007/10/02)
The first synthesis of cotarnone (2), a degradation product of cotarnine (1), was achieved from 2-hydroxy-3-methoxybenzaldehyde (o-vanilin), and 2 can be converted to 1 by a known method.
