201677-20-5Relevant articles and documents
Method for synthesizing chiral N-substituted-alpha-amino acid compound through chemical resolution
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Paragraph 0052-0053; 0055, (2020/03/11)
The invention belongs to the technical field of preparation of N-substituted-alpha-amino acid compounds, and particularly relates to a method for synthesizing a chiral N-substituted-alpha-amino acid compound through chemical resolution. The method comprises the following steps: mixing a racemate N-substituted-alpha-amino acid compound with phenylglycinol to form a salt, and adding an acid for neutralization to obtain a single-configuration chiral target product, wherein the N-substituted-alpha-amino acid compound is N-substituted-2-amino-4,4-dimethyl valeric acid, and an N-substituted amino protecting group is an alkoxycarbonyl group, an enoxycarbonyl group, an aryloxycarbonyl group or an alkylacyl group. According to the method, chiral phenylglycinol which is low in cost and stable in property is used as a resolution reagent, and N-substituted alpha-amyl amino acid can be well resolved; and R-configuration or S-configuration enantiomers are respectively obtained. The method is high inyield, good in purity, low in cost and suitable for industrial production.
Protease inhibitors
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, (2008/06/13)
The present invention provides compounds of formula (I) which inhibit proteases, including cathepsin K, pharmaceutical compositions of such compounds, and methods for treating diseases of excessive bone loss or cartilage or matrix degradation, including osteoporosis; gingival disease including gingivitis and periodontitis; arthritis, more specifically, osteoarthritis and rheumatoid arthritis; Paget's disease; hypercalcemia or malignancy; and metabolic bone disease therewith.
Conversion of Serine β-Lactones to Chiral α-Amino Acids by Copper-Containing Organolithium and Organomagnesium Reagents
Arnold, Lee D.,Drover, John C. G.,Vederas, John C.
, p. 4649 - 4659 (2007/10/02)
A method for the synthesis of optically pure α-amino acids has been developed.Mono- and di-N-protected α-amino-β-lactones 3a (L, R1=H, R2=COOCH2Ph (Z)), 3b (D, R1=H, R2=Z), 3c (L, R1=CH2Ph, R2=Z), and 3d (D, R1=CH2Ph, R2=Z) are readily produced by cyclization of the corresponding serine derivatives 2 under modified Mitsunobu conditions without loss of optical purity.Stereochemical integrity was demonstrated by conversion of 3 to 2-methoxy-2-(trifluoromethyl)phenylacetate esters 6 and analysis by HPLC, (19)F NMR, and (1)H NMR.Reaction of 3 with organolithium-derived cuprate reagents (R2CuLi or R2Cu(CN)Li2) at low temperature produces N-protected α-amino acids by attack at the β-methylene group.Yields of di-N-protected amino acids are generally higher (ca. 50-75percent), but some decrease in enantiomeric excess (ee) can occur (0-27percent).In contrast, the mono-N-protected β-lactones 3a and 3b give slightly lower yields (ca. 44-62percent) but negligible decrease in ee (0-1.7percent) with the exception of Ph2Cu(CN)Li2 (67percent loss of ee).However, the use of Cu(I)-catalyzed Grignard (RMgCl) additions gives better yields (44-83percent), complete retention of optical purity ( 99.4percent), and fewer side products.Reductive removal of the protecting groups in a single step (H2/Pd-C or Na/NH3) affords the free α-amino acids in 91-99percent yield.Their stereochemical purity was determined by conversion to the corresponding N-(-)-camphanoyl methyl esters and analysis by gas chromatography and (1)H NMR spectroscopy.
