97672-26-9

Upstream product

• 35660-94-7 (Z)-2-methyl-2-butenoyl chloride 
• 2216-51-5 (-)-menthol 
• 66069-77-0 (E)-3-bromo-2-methyl-but-2-enoyl chloride 
• 35057-99-9 (E)-3-bromo-2-methylbut-2-enoic acid 
• 5953-76-4 methyl angelate 
• 565-63-9 Angelic acid 
• 18419-38-0 (-)-menthol trimethylsilyl ether 
• 55517-33-4 trimethylsilyl angelate 

Downstream Products

• 609358-96-5 (4R,5R)-2,2,4,5-Tetramethyl-[1,3]dioxolane-4-carboxylic acid (1R,2S,5R)-2-isopropyl-5-methyl-cyclohexyl ester 
• 609358-97-6 (R)-Benzylamino-((4S,5R)-2,2,4,5-tetramethyl-[1,3]dioxolan-4-yl)-acetonitrile 

Relevant academic research and scientific papers

Semisynthesis of ingenol 3-angelate (PEP005): Efficient stereoconservative angeloylation of alcohols

A high-yielding method was developed for the preparation of ingenol 3-angelate (PEP005, ingenol mebutate) via the corresponding 5,20-acetonide without concomitant isomerization of the angelate (Z-form) to the corresponding tiglate (E-form). The general sc

Total synthesis of thiostrepton. Retrosynthetic analysis and construction of key building blocks

The first phase of the total synthesis of thiostrepton (1), a highly complex thiopeptide antibiotic, is described. After a brief introduction to the target molecule and its structural motifs, it is shown that retrosynthetic analysis of thiostrepton reveals compounds 23, 24, 26, 28, and 29 as potential key building blocks for the projected total synthesis. Concise and stereoselective constructions of all these intermediates are then described. The synthesis of the dehydropiperidine core 28 was based on a biosynthetically inspired aza-Diels-Alder dimerization of an appropriate azadiene system, an approach that was initially plagued with several problems which were, however, resolved satisfactorily by systematic investigations. The quinaldic acid fragment 24 and the thiazoline-thiazole segment 26 were synthesized by a series of reactions that included asymmetric and other stereoselective processes. The dehydroalanine tail precursor 23 and the alanine equivalent 29 were also prepared from the appropriate amino acids. Finally, a method was developed for the direct coupling of the labile dehydropiperidine key building block 28 to the more advanced and stable peptide intermediate 27 through capture with the highly reactive alanine equivalent 67 under conditions that avoided the initially encountered destructive ring contraction process.

Synthetic studies on thiostrepton: Construction of thiostrepton analogues with the thiazoline-containing macrocycle

Leading the way: The novel thiostrepton analogue 1 and its 5S, 6S diastereomer were synthesized through macrolactamization reactions. Forays towards the total synthesis of the natural product itself should follow a similar strategy.

Enantioselective preparation of (2R,3R)-(+)- and (2S,3S)-(-)-2,3-epoxy- 2-methylbutanoic acids and some derivatives

(2R,3R)-(+)- and (2S,3S)-(-)-2,3-epoxy-2-methylbutanoic acids (epoxyangelic acids) were prepared from (Z)-2-methyl-2-butenoic acid using the Sharpless asymmetric epoxidation method in combination with the use of (- )- and (+)-menthol as chiral auxiliaries. Both substances, obtained in high enantiomeric excess, were characterized by spectroscopic and optical activity data. Their absolute configuration was determined by correlation with (R)- (+)-2-methyl-1,2-butanediol.

A New and Efficient Esterification Reaction via Mixed Anhydrides by the Promotion of a Catalytic Amount of Lewis Acid

In the presence of a catalytic amount of Lewis acid, various carboxylic esters or S-phenyl carbothioates are prepared in excellent yields by the respective reactions of equimolar amounts of silyl carboxylates and alkyl silyl ethers or phenyl silyl sulfides with 4-trifluoromethylbenzoic anhydride.