Intramolecular nitrile oxide cycloaddition (INOC) reactions in the indole series. 2. Total synthesis of racemic and optically active paliclavine and 5-epi-paliclavine

Abstract

The first total synthesis of the ergot alkaloid paliclavine and the formal total synthesis of paspaclavine in optically active form are described.

MgI2‐chemoselective cleavage for removal of amino acid protecting groups: A fresh vision for peptide synthesis

“…Regarding the most popular PGs N ‐Tos, N ‐Pmc, or N ‐Pbf, engaged to mask the guanidine group of arginine, and usually removed in acidic conditions, they remained unaffected under MgI 2 ‐MW experimental conditions (Table , entries 19–20, 23–24), offering, along with the cyclohexyl group, an orthogonal strategy for the solid phase peptide synthesis on the Merrifield resin (Table , entry 25).…”

Synthesis of hydroxydiamines and triamines via reductive cleavage of N–N bond in substituted pyrazolidines

“…The reduction by active metals (Aeberli and Houlihan 1969) or boron compounds (Feuer and Brown 1970), hydrogenation on platinum group metals (Stetter and Findeisen 1965), and application of hydrazine hydrate on Raney nickel (Robinson and Brown 1961) should be mentioned as the most widely used methods. A number of chiral compounds, for example, c-amino alcohols, or some other bifunctional compounds (Tufariello 1979;Kozikowski and Chen 1981;Kozikowski and Adamczyk 1983) have been obtained via N-O bond breaking in chiral isoxazolines and isoxazolidines. However, the reductive cleavage of chiral functionally substituted pyrazolidines and pyrazolines has not been studied yet.…”

Chalcone Ditosylates as Potent Precursor for Synthesis of Some 4,5-Disubstituted Isoxazoles with Antioxidant and Anti-inflammatory Activities

“…Isoxazole derivatives have been useful as a versatile building block for the synthesis of organic compounds. Isoxazoles can be converted into various important synthetic units like βhydroxy ketones [1][2][3][4][5][6][7], γ-amino alcohols [8,9], α,β-unsaturated oxime [10,11] and β-hydroxy nitriles [12,13]. Along with these, isoxazole derivatives have been used in synthetic investigation as of their known biological activities and pharmacological properties like hypoglycemic effect [14], analgesic [15], anti-inflammatory [16], antibacterial activities [17] and anticancer activity [18].…”