16881-39-3Relevant articles and documents
Asymmetric Catalytic Hydrogenations of N-Pyruvoyl-(S)-proline Esters
Munegumi, Toratane,Fujita, Manabu,Maruyama, Tetsuya,Shiono, Shozo,Takasaki, Michiaki,Harada, Kaoru
, p. 249 - 254 (1987)
Asymmetric catalytic hydrogenations of the entitled compounds were carried out over palladium on charcoal in various solvents to afford N--(S)-proline esters with a d.e.(=diastereoisomeric excess) of up to 59percent.The stereochemistry of the catalytic hydrogenation was explained by the "chelation mechanism." And the effects of temperature and bulkiness of the ester groups on the asymmetric induction were also described.
Ring-Strain Effects in Base-Induced Sommelet–Hauser Rearrangement: Application to Successive Stereocontrolled Transformations
Tayama, Eiji,Watanabe, Kazutoshi,Matano, Yoshihiro
, p. 3631 - 3641 (2016/07/29)
The base-induced Sommelet–Hauser (S–H) rearrangement of azetidine-2-carboxylic acid ester-derived ammonium salts into 2-aryl-substituted derivatives was demonstrated. The ring-strain of four-membered N-heterocycles enables efficient generation of the desired ylide intermediate and enhances the rate of the S–H rearrangement. The asymmetric version of the rearrangement was characterized by excellent levels of successive chirality transmissions. The regio- and stereo-controlled nucleophilic ring opening of the rearrangement products produced quaternary α-aryl amino acid esters with excellent enantiopurities.
Total synthesis of wewakazole B
Long, Bohua,Zhang, Jingzhao,Tang, Xudong,Wu, Zhengzhi
supporting information, p. 9712 - 9715 (2016/10/31)
Wewakazole B is a novel cyclodecapeptide with highly potent cytotoxic activity isolated from a sample of M. producens collected from the Red Sea. It contains nine common and three modified amino acid residues. The first total synthesis of Wewakazole B was successfully achieved on a gram scale, unambiguously confirming its structure. Notable features include the careful choice of amino acid-protecting groups and the construction of three different substituted oxazoles present in this natural product.
Convenient and Simple Esterification in Continuous-Flow Systems using g-DMAP
Okuno, Yoshinori,Isomura, Shigeki,Sugamata, Anna,Tamahori, Kaoru,Fukuhara, Ami,Kashiwagi, Miyu,Kitagawa, Yuuichi,Kasai, Emiri,Takeda, Kazuyoshi
, p. 3587 - 3589 (2015/11/17)
The utility and applicability of polyethylene-g-polyacrylic acid-immobilized dimethylaminopyridine (g-DMAP) as a catalyst in a continuous-flow system were investigated for decarboxylative esterification. High catalytic activity toward acylation was provided by g-DMAP containing a flexible grafted-polymer structure. During decarboxylation, carboxylic acids and alcohols were converted cleanly using di-tert-butyl dicarbonate (Boc2O) as a coupling reagent, which reduced by-products. In addition, the use of Boc2O resulted in the formation of tert-butyl esters. These esterifications dramatically reduced the reaction time under continuous-flow conditions, with a residence time of approximately 2 min. This highly efficient esterification procedure will provide more practical industrial applications.
Solventless mechanosynthesis of N-protected amino esters
Konnert, Laure,Lamaty, Frederic,Martinez, Jean,Colacino, Evelina
, p. 4008 - 4017 (2014/05/20)
Mechanochemical derivatizations of N- or C-protected amino acids were performed in a ball mill under solvent-free conditions. A vibrational ball mill was used for the preparation of N-protected α- and β-amino esters starting from the corresponding N-unmasked precursors via a carbamoylation reaction in the presence of di-tert-butyl dicarbonate (Boc2O), benzyl chloroformate (Z-Cl) or 9-fluorenylmethoxycarbonyl chloroformate (Fmoc-Cl). A planetary ball mill proved to be more suitable for the synthesis of amino esters from N-protected amino acids via a one-pot activation/esterification reaction in the presence of various dialkyl dicarbonates or chloroformates. The spot-to-spot reactions were straightforward, leading to the final products in reduced reaction times with improved yields and simplified work-up procedures.
Practical one-pot double functionalizations of proline
Huy, Peter,Schmalz, Hans-Guenther
, p. 954 - 960 (2011/05/07)
Solubilization of proline as the triethylammonium salt allows N-protection (as the Boc, Cbz or Moc derivative) and subsequent esterification or amidation of the carboxy terminus to be performed in an efficient one-pot fashion. Based on this concept, highly practical protocols were developed to prepare a series of proline derivatives (including Pro-Ser dipetides, Weinreb amides and N-protected proline esters), which are important intermediates, for instance, for the synthesis of proline-derived peptides, chiral reagents and catalysts for asymmetric synthesis. Georg Thieme Verlag Stuttgart - New York.
Direct electrochemical α-cyanation of N-protected cyclic amines
Libendi, Samuel Shikuku,Demizu, Yosuke,Onomura, Osamu
experimental part, p. 351 - 356 (2009/03/12)
α-Cyanation of N-protected cyclic amines was achieved using a direct electrochemical method. Unsubstituted N-protected cyclic amines were easily cyanated at the α-position using an undivided cell in high yields; moreover, α-cyanation of α′-substituted pyrrolidine and α′-,β′- or γ-substituted piperidines smoothly proceeded in high yield and with high to excellent diastereoselectivity. α-Substituted N-cyano-pyrrolidines and -piperidines were also cyanated at the more substituted position (the α-position) using a divided cell with high yield and high regioselectivity.
Domino catalysis in the direct conversion of carboxylic acids to esters
Held,Von Den Hoff,Stephenson,Zipse
supporting information; experimental part, p. 1891 - 1900 (2009/08/07)
The combined use of high concentration conditions, auxiliary bases, and new catalysts allows for the rapid synthesis of sterically hindered carboxylic acid esters at room temperature. Mechanistic analysis indicates the intermediate formation of acid anhydrides and subsequent rate-limiting transformation to the ester products.
Asymmetric [1,2] Stevens rearrangement of (S)-N-benzylic proline-derived ammonium salts under biphasic conditions
Tayama, Eiji,Nanbara, Shintaro,Nakai, Takeshi
, p. 478 - 479 (2007/10/03)
The Stevens rearrangement of (S)-N-benzylic proline-derived ammonium salt with cesium hydroxide in 1,2-dichloroethane is shown to proceed with a high degree of the N-to-C chirality transmission to afford the α-substituted proline derivatives in high enantio-purities. Copyright
Conformationallly constrained peptidomimetics as β-turn templates and modulators of SH3 domains
-
, (2008/06/13)
Spirolactam compounds useful as inhibitors of protein-protein interactions modulated by SH3 domains are disclosed. Compounds of the invention are also useful as β-turn mimetics. Also disclosed are libraries of compounds of the invention, pharmaceutical compositions of the compounds of the invention, and methods for using the compounds of the invention to inhibit growth of a cell or to inhibit protein-protein interactions modulated by SH3 domains.
