- METHOD OF 4-BORONOPHENYLALANINE PRODUCTION
-
The present invention relates to a method of production of 4-boronophenylalanine (BPA) from 4-iodophenylalanine, in which all the functional groups of the amino acid are protected by benzyl protection method, and which uses isopropyl magnesium halogenide stabilized by a complexation base, and subsequent condensation of the resulting Grignard reagent with a boric acid ester. The final reaction step, catalytic hydrogenolysis or transfer hydrogenolysis of protecting groups on the amino acid, occurs after hydrolysis of the boronate ester groups.
- -
-
-
- METHOD FOR PREPARING L-BPA
-
Provided is a method for preparing L-BPA, which includes steps of: reacting N-protected (S)-4-halophenylalanine of Formula I, a boronating agent, Grignard reagent and bis(2-methylaminoethyl)ether to obtain a reaction mixture, wherein the reaction mixture comprises N-protected (S)-4-boronophenylalanine of Formula II and the R2 group represents a protecting group; isolating the N-protected (S)-4-boronophenylalanine from the reaction mixture; and deprotecting the R2 group of the N-protected (S)-4-boronophenylalanine to obtain L-BPA, wherein the L-BPA has a structure of Formula III.
- -
-
Paragraph 0123-0128
(2018/06/15)
-
- Process for preparing 4-Borono-L-Phenylalanine
-
Provided is a process for preparing 4-borono-L-phenylalanine, which has steps of: reacting N-protected (S)-4-halophenylalanine of formula (I), a boronating agent and an organolithium to obtain a reaction mixture, wherein the reaction mixture comprises the N-protected (S)-4-boronophenylalanine of formula (II) and the R group represents a protection group; isolating the N-protected (S)-4-boronophenylalanine from the reaction mixture; deprotecting the R group of the N-protected (S)-4-boronophenylalanine to obtain L-BPA.
- -
-
Paragraph 0077; 0078
(2015/05/06)
-
- Compositions, methods of preparing amino acids, and nuclear magnetic resonance spectroscopy
-
The present invention relates to amino acids, complexes, and compounds comprising deuterium and tritium isotopes preferably alpha deuterated amino acids, polypeptides, antibodies, derivatives and saccharide-amino acid complexes and conjugates. In some embodiments, the invention relates to methods of using compounds comprising deuterium for imaging biochemical concentrations and distributions in mammalian tissues using nuclear magnetic resonance spectroscopy. In some embodiments, the invention relates to the used of said amino acids derivatives and complexes in boron neutron capture therapy. In some embodiments, the present invention relates to the preparation of amino acids, polypeptides, antibodies, derivatives and saccharide complexes/conjugates comprising heavy hydrogen isotopes. In some embodiments, the invention relates to racemizing amino acids starting from compositions of any optical purity. In further embodiments, the invention relates to the preparation of amino acids and their N-acyl counterparts with deuterium incorporated at the alpha carbon.
- -
-
Page/Page column 13; sheet 3
(2010/11/27)
-
- A practical method for the synthesis of enantiomerically pure 4-borono- L-phenylalanine
-
Enantiomerically pure L-BPA (4-borono-L-phenylalanine) was synthesized from L-tyrosine or 4-iodo-L-phenylalanine derivatives using the palladium- catalyzed cross-coupling reaction of pinacolborane (2,3-dimethyl-2,3- butanediolatoboron). Cbz-Tyr(Nf)-OBzl (2b) underwent the cross-coupling reaction with pinacolborane (1) in the presence of [PdCl2(PPh3)2] catalyst to give N-benzyloxycarbonyl-4-(2,3-dimethyl-2,3-butanediolatoboryl)-L- phenylalanine benzyl ester (3a) in 58% yield. The reaction of the 4-iodo-L- phenylalanine derivatives, such as N-benzyloxycarbonyl-4-iodo-L-phenylalanine benzyl ester (2c), N,N-dibenzyl-4-iodo-L-phenylalanine benzyl ester (2d), (4S)-3-benzyloxycarbonyl-4-(4-iodobenzyl)-5-oxazolidinone (2e), and (4S)-3-t- butyloxycarbonyl-4-(4-iodobenzyl)-5-oxazolidinone (2f), with 1 proceeded very smoothly in the presence of [PdCl2(dppf)] catalyst, giving N- benzyloxycarbonyl-4-(2,3-dimethyl-2,3-butanediolatoboryl)-L-phenylalanine benzyl ester (3a), N,N-dibenzyl-4-(2,3-dimethyl-2,3-butanediolatoboryl)-L- phenylalanine benzyl ester (3b), (4S)-3-benzyloxycarbonyl-4-[4-(2,3-dimethyl- 2,3-butanediolatoboryl)benzyl]-5-oxazolidinone (3c), and (4S)-3- butyloxycarbonyl-4-[4(2,3-dimethyl-2,3-butanediolatoboryl)benzyl]-5- oxazolidinone (3d), respectively, in high yields. Deprotection of 3a-d gave enantiomerically pure L-BPA in high total yields.
- Nakamura, Hiroyuki,Fujiwara, Masaru,Yamamoto, Yoshinori
-
p. 231 - 235
(2007/10/03)
-
- Process for preparing L-p-boronophenylalanine and intermediate for preparing the same
-
There is disclosed a process for preparing L-p-boronophenylalanine which comprises subjecting a compound represented by the formula: wherein Y represents a protective group selected from the group consisting of benzyloxycarbonyl group, allyloxycarbonyl group and t-butoxycarbonyl group; and Bn represents benzyl group, to hydrogenation reaction in the presence of a palladium series catalyst, and a synthetic intermediate represented by the above formula for preparing the same.
- -
-
-
- A high-yield synthesis of 4-borono-DL-phenylalanine
-
A high-yield synthesis of 4-borono-DL-phenylalanine has been achieved by a route which features a highly diastereoselective formation of the Z-isomer of a boron-containing dehydroamino acid derivative.
- Park, Ki Chul,Yoshino, Kazuo,Tomiyasu, Hiroshi
-
p. 2041 - 2044
(2007/10/03)
-
