208709-76-6Relevant articles and documents
Practical syntheses of chiral α-amino acids and chiral half-esters by kinetic resolution of urethane-protected α-amino acid N-carboxyanhydrides and desymmetrization of cyclic meso-anhydrides with new modified cinchona alkaloid catalysts
Ishii, Yutaka,Fujimoto, Ryosuke,Mikami, Masafumi,Murakami, Satoshi,Miki, Yasushi,Furukawa, Yoshiro
, p. 609 - 615 (2007)
The large-scale applications of the kinetic resolution of urethane-protected α-amino acid N-carboxyanhydrides (UNCAs) and the desymmetrization of cyclic meso-anhydrides using modified cinchona alkaloids are described. These asymmetric reactions are effective organocatalytic methods for the synthesis of chiral a-amino acids 6 and chiral half-esters 2 on an industrial scale, because the organocatalyst recovery and product purification can be carried out by a simple extractive procedure obviating a chromatographic purification step. The modified cinchona alkaloid catalysts (DHQD) 2AQN and (DHQ)2AQN, as reported by Deng and co-workers, are not readily available and therefore not suitable for industrial-scale synthesis. Various O-alkylated quinidine and quinine derivatives were prepared and screened as catalysts for the kinetic resolution of phenylalanine UNCA with alcohol. The readily prepared O-propargylquinidine (OPQD) and O-propargylquinine (OPQ) were discovered to be highly enantioselective and practical catalysts. These new catalysts were applied to the synthesis of chiral propargylglycine 24 and the key intermediate of BAY10-8888/PLD-118, 26, on an industrial scale, by the kinetic resolution of UNCA 22 and the desymmetrization of cyclic meso-anhydride 25, respectively.
α-Propargyl amino acid-derived optically active novel substituted polyacetylenes: Synthesis, secondary structures, and responsiveness to ions
Sogawa, Hiromitsu,Shiotsuki, Masashi,Sanda, Fumio
experimental part, p. 2008 - 2018 (2012/07/13)
Novel optically active substituted acetylenes HCi￡ CCH 2CR1(CO2CH3)NHR2 [(S)-/(R)-1: R1 = H, R2 = Boc, (S)-2: R1 = CH3, R2 = Boc, (S)-3: R1 = H, R2 = Fmoc, (S)-4: R1 = CH3, R2 = Fmoc (Boc = tert-butoxycarbonyl, Fmoc = 9-fluorenylmethoxycarbonyl)] were synthesized from α-propargylglycine and α-propargylalanine, and polymerized with a rhodium catalyst to provide the polymers with number-average molecular weights of 2400-38,900 in good yields. Polarimetric, circular dichroism (CD), and UV-vis spectroscopic analyses indicated that poly[(S)-1], poly[(R)-1], and poly[(S)-4] formed predominantly one-handed helical structures both in polar and nonpolar solvents. Poly[(S)-1a] carrying unprotected carboxy groups was obtained by alkaline hydrolysis of poly[(S)-1], and poly[(S)-4b] carrying unprotected amino groups was obtained by removal of Fmoc groups of poly[(S)-4] using piperidine. Poly[(S)-1a] and poly[(S)-4b] also exhibited clear CD signals, which were different from those of the precursors, poly[(S)-1] and poly[(S)-4]. The solution-state IR measurement revealed the presence of intramolecular hydrogen bonding between the carbamate groups of poly[(S)-1] and poly[(S)-1a]. The plus CD signal of poly[(S)-1a] turned into minus one on addition of alkali hydroxides and tetrabutylammonium fluoride, accompanying the red-shift of λmax. The degree of λmax shift became large as the size of cation of the additive.
Novel Compounds
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Page/Page column 23, (2009/12/05)
The invention provides a compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein R is C1-4 alkyl useful in the treatment of diseases and conditions for which antagonism of NK1 receptor is beneficial.
