16874-02-5Relevant academic research and scientific papers
Scavenging of fluorinated N,N′-dialkylureas by hydrogen binding: A novel separation method for fluorous synthesis
Palomo, Claudio,Aizpurua, Jesus M.,Loinaz, Iraida,Fernandez-Berridi, Maria Jose,Irusta, Lourdes
, p. 2361 - 2364 (2001)
(matrix presented) A dramatic solubility increase in fluorous solvents is observed for N,N′-di(polyfluoroalkyl)ureas when hydrogen binding complexes are formed with commercially available perfluoroalkanoic acid scavengers. As a case example, analytically pure peptides and esters are obtained using this novel separation method.
Visible Light Induced Cu-Catalyzed Asymmetric C(sp3)-H Alkylation
Chai, Hongli,Huo, Yumei,Liu, Liangyu,Ma, Zijian,Qi, Rupeng,Wang, Chao,Wang, Hongying,Wang, Rui,Xu, Zhaoqing
supporting information, p. 12777 - 12783 (2021/08/31)
The asymmetric functionalization of C-H is one of the most attractive strategies in asymmetric synthesis. In the past decades, catalytic enantioselective C(sp3)-H functionalization has been intensively studied and successfully applied in various asymmetri
Chiral tetraaryl-and tetraalkynylborates as chiral solvating agents for tetraalkylammonium salts
Tayama, Eiji,Sugawara, Takeshi
, p. 803 - 811 (2019/01/18)
The application of tetracarbon-substituted chiral borate sodium salts (NaBR*4) as NMR chiral solvating agents for various tetraalkylammonium salts (R4NX) has been successfully demonstrated. Ion exchange between R4NX and NaBR*4 proceeded in excellent yields and provided the corresponding dia-stereomeric salts (R4NBR*4). The ee values of the R4NX salts were determined by1H NMR analysis of R4NBR*4. Two types of chiral borates, tetraaryl-and tetraalkynylborates with optically active 1,1′-binaphthyl components were used. At the beginning of this research, we investigated the efficacy of a known chiral tetraar-ylborate developed by Pommerening et al. for R4NX. To expand the possibility of further structural design of the chiral borate, we designed chiral tetraalkynylborates as a new structure. Their synthesis and application are also described.
Design, synthesis, and biological evaluation of novel dipeptide-type SARS-CoV 3CL protease inhibitors: Structure-activity relationship study
Thanigaimalai, Pillaiyar,Konno, Sho,Yamamoto, Takehito,Koiwai, Yuji,Taguchi, Akihiro,Takayama, Kentaro,Yakushiji, Fumika,Akaji, Kenichi,Kiso, Yoshiaki,Kawasaki, Yuko,Chen, Shen-En,Naser-Tavakolian, Aurash,Sch?n, Arne,Freire, Ernesto,Hayashi, Yoshio
, p. 436 - 447 (2013/10/01)
This work describes the design, synthesis, and evaluation of low-molecular weight peptidic SARS-CoV 3CL protease inhibitors. The inhibitors were designed based on the potent tripeptidic Z-Val-Leu-Ala(-pyrrolidone-3-yl)-2-benzothiazole (8; Ki = 4.1 nM), in which the P3 valine unit was substituted with a variety of distinct moieties. The resulting series of dipeptide-type inhibitors displayed moderate to good inhibitory activities against 3CLpro. In particular, compounds 26m and 26n exhibited good inhibitory activities with Ki values of 0.39 and 0.33 μM, respectively. These low-molecular weight compounds are attractive leads for the further development of potent peptidomimetic inhibitors with pharmaceutical profiles. Docking studies were performed to model the binding interaction of the compound 26m with the SARS-CoV 3CL protease. The preliminary SAR study of the peptidomimetic compounds with potent inhibitory activities revealed several structural features that boosted the inhibitory activity: (i) a benzothiazole warhead at the S1′ position, (ii) a γ-lactam unit at the S1-position, (iii) an appropriately hydrophobic leucine moiety at the S2-position, and (iv) a hydrogen bond between the N-arylglycine unit and a backbone hydrogen bond donor at the S3-position.
Asymmetric α-2-tosylethenylation of N,N-dialkyl-l-amino acid esters via the formation of non-racemic ammonium enolates
Tayama, Eiji,Igarashi, Tomohito,Iwamoto, Hajime,Hasegawa, Eietsu
supporting information; experimental part, p. 339 - 345 (2012/01/19)
Asymmetric α-2-tosylethenylation of (S)-2-(pyrrolidin-1-yl)propanoic acid esters was shown to produce good yields with high enantioselectivities. The reaction proceeds via the formation of a non-racemic ammonium enolate without an external source of chirality.
Facile synthesis of tert-butyl ester of N-protected amino acids with tert-butyl bromide
Chevallet, Pierre,Garrouste, Patrick,Malawska, Barbara,Martinez, Jean
, p. 7409 - 7412 (2007/10/02)
A facile synthesis of a wide variety of N-benzyloxycarbonyl-amino acid-tert-butyl ester derivatives under mild conditions is described. N-protected amino acids were esterified with tert-butyl bromide in dimethylacetamide as solvent, in the presence of benzyltriethylammonium chloride (BTEAC)and a large excess of potassium carbonate. Many amino Z-acid-Tert-butyl esters that might be difficult to prepare by other methods have been synthesized in high yields by this procedure. The reaction is simple, unexpansive, easily scaled up, and proceeds without observable racemization.
ISOPROPENYL CHLOROCARBONATE (IPCC) IN AMINO ACID AND PEPTIDE CHEMISTRY: ESTERIFICATION OF N-PROTECTED AMINO ACIDS; APPLICATION TO THE SYNTHESIS OF THE DEPSIPEPTIDE VALINOMYCIN
Zeggaf, Choukri,Poncet, Joel,Jouin, Patrick,Dufour, Marie-Noelle,Castro, Bertrand
, p. 5039 - 5050 (2007/10/02)
Esterification of N-protected α-amino acids was achieved via isopropenyl chlorocarbonate (IPCC) activation.In situ alcoholysis of the unstable mixed anhydride intermediate was catalised by 4-(dimethylamino)pyridine (DMAP).Competing isopropenyl ester formation was negligible when using methylene chloride as the solvent.A variety of esters from primary and secondary alcohols were obtained with good yields (60 to 90 percent), and even the more hindered tertiobutyl alcohol gave acceptable yields under more drastic conditions.The improvement in depsipeptide synthetic methodology is illustrated by preparation of the antibiotic valinomycin, using IPCC for ester bond formation, and BOP reagent for peptide coupling and the last-step cyclisation.
Cyclic esters of 3,4-dihydroxy-thiophene-1,1-dioxide compounds and 3,4-dihydroxy-cyclopentadienone compounds
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, (2008/06/13)
Cyclic esters of 3,4-dihydroxy-thiophene-1,1-dioxide and of the corresponding cyclopentadienone compound, and their manufacture. The compounds can be used as "solid forms" of phosgene, thiophosgene or oxalyl chloride, or as acyl transfer agents.
