22838-58-0Relevant articles and documents
A Facile Approach to the Synthesis of Benzothiazoles from N-Protected Amino Acids
Arfan, M.,Fatima, T.,Mannan, A.,Tahira, A.
, p. 292 - 297 (2020/04/21)
Abstract: –A simple trituration method for the synthesis of 2-substituted benzothiazoles derived from N-protected amino acids and 2-aminothiophenol using molecular iodine as a mild Lewis acid catalyst has been proposed. The reaction occurs in one step for 20–25 min in solve-free conditions and provides the target products in excellent yields.
HMOX1 inducers
-
Page/Page column 59, (2020/09/18)
The present invention is related to compounds of structure (I) as heme oxygenase 1 (HMOX 1) inducers. The present invention is also related a method of controlling the activity or the amount, or both the activity and the amount, of heme-oxygenase 1 in a mammalian subject. The definitions of the variables are provided herein.
Amino acid conjugated antimicrobial drugs: Synthesis, lipophilicity- activity relationship, antibacterial and urease inhibition activity
Ullah, Atta,Iftikhar, Fatima,Arfan, Muhammad,Batool Kazmi, Syeda Tayyaba,Anjum, Muhammad Naveed,Haq, Ihsan-ul,Ayaz, Muhammad,Farooq, Sadia,Rashid, Umer
, p. 140 - 153 (2018/01/10)
Present work describes the in vitro antibacterial evaluation of some new amino acid conjugated antimicrobial drugs. Structural modification was attempted on the three existing antimicrobial pharmaceuticals namely trimethoprim, metronidazole, isoniazid. Twenty one compounds from seven series of conjugates of these drugs were synthesized by coupling with some selected Boc-protected amino acids. The effect of structural features and lipophilicity on the antibacterial activity was investigated. The synthesized compounds were evaluated against five standard American type culture collection (ATCC) i.e. Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi strains of bacteria. Our results identified a close relationship between the lipophilicity and the activity. Triazine skeleton proved beneficial for the increase in hydrophobicity and potency. Compounds with greater hydrophobicity have shown excellent activities against Gram-negative strains of bacteria than Gram-positive. 4-amino unsubstituted trimethoprim-triazine derivative 7b have shown superior activity with MIC = 3.4 μM (2 μg/mL) for S. aureus and 1.1 μM (0.66 μg/mL) for E. coli. The synthesized compounds were also evaluated for their urease inhibition study. Microbial urease from Bacillus pasteurii was chosen for this study. Triazine derivative 7a showed excellent inhibition with IC50 = 6.23 ± 0.09 μM. Docking studies on the crystal structure of B. pasteurii urease (PDB ID 4UBP) were carried out.
Enantioselective Synthesis of Quaternary Δ4- and Δ5-Dehydroprolines Based on a Two-Step Formal [3+2] Cycloaddition of α-Aryl and α-Alkyl Isocyano(thio)acetates with Vinyl Ketones
Odriozola, Amaiur,Oiarbide, Mikel,Palomo, Claudio
supporting information, p. 12758 - 12762 (2017/09/25)
A divergent synthesis of optically active quaternary Δ4- and Δ5-dehydro prolines is developed based on the first catalytic enantioselective conjugate addition of α-substituted isocyano(thio)acetates to vinyl ketones that is general for both α-aryl and α-alkyl isocyano(thio)acetates. The new tetrasubstituted C?N stereocenter is formed without the need of any metal salt due to a bifunctional tertiary amine/squaramide catalyst, featuring a bulky polyaryl sidearm and an unusually short squaramide diamide H???H interatomic distance in the solid state.
Chemo- and Diastereoselective N-Heterocyclic Carbene-Catalyzed Cross-Benzoin Reactions Using N-Boc-α-amino Aldehydes
Haghshenas, Pouyan,Gravel, Michel
supporting information, p. 4518 - 4521 (2016/09/28)
N-Boc-α-amino aldehydes are shown to be excellent partners in cross-benzoin reactions with aliphatic or heteroaromatic aldehydes. The chemoselectivity of the reaction and the facial selectivity on the amino aldehyde allow cross-benzoin products to be obtained in good yields and good diastereomeric ratios. The developed method is utilized as the key step in a concise total synthesis of d-arabino-phytosphingosine.
Liquid chromatographic resolution of amino acid esters of acyclovir including racemic valacyclovir on crown ether-based chiral stationary phases
Ahn, Seong Ae,Hyun, Myung Ho
, p. 268 - 273 (2015/03/18)
Valacyclovir, a potential prodrug for the treatment of patients with herpes simplex and herpes zoster, and its analogs were resolved on two chiral stationary phases (CSPs) based on (3,3′-diphenyl-1,1′-binaphthyl)-20-crown-6 covalently bonded to silica gel. In order to find out an appropriate mobile phase condition, various mobile phases consisting of various organic modifiers in water containing various acidic modifiers were applied to the resolution of valacyclovir and its analogs. When 30% acetonitrile in water containing any of 0.05 M, 0.10 M, or 0.15 M perchloric acid was used as a mobile phase, valacyclovir and its analogs were resolved quite well on the two CSPs with the separation factors (α) in the range of 2.49~6.35 and resolutions (RS) in the range of 2.95 ~ 12.21. Between the two CSPs, the CSP containing residual silanol protecting n-octyl groups on the silica surface was found to be better than the CSP containing residual silanol groups.
Highly enantioselective fluorescent recognition of amino acid derivatives by unsymmetrical salan sensors
Yang, Xia,Shen, Kang,Liu, Xuechao,Zhu, Chengjian,Cheng, Yixiang
scheme or table, p. 4611 - 4614 (2011/10/01)
Novel unsymmetrical salan fluorescent sensors 2a and 2b have been designed and synthesized. The chiral recognition of N-Boc-protected amino acids by 2a and 2b has been investigated. Sensor 2a possesses higher sensitivity and enantioselectivity than sensor 2b does. Job analysis and nonlinear regression results show that 2a can form a 1:1 stoichiometric complex with a N-Boc-protected amino acid. The obtained response selectivities and the association constants indicate that 2a is a highly enantioselective and sensitive fluorescent sensor toward N-Boc-protected amino acids.
Enantiomeric resolution of α-amino acid derivatives on two diastereomeric chiral stationary phases based on chiral crown ethers incorporating two different chiral units
Kim, Hee Jin,Choi, Hee Jung,Cho, Yoon Jae,Hyun, Myung Ho
body text, p. 1551 - 1554 (2010/10/20)
Two diastereomeric chiral stationary phases (CSPs) were applied to the liquid chromatographic resolution of various racemic a-amino methyl esters, α-amino N,N-diethylamides and α-amino N-propylamides. The CSP incorporating (R)-3,3' -diphenyl-1,1' -binaphtyl and (R,R)-tartaric acid unit as chiral barriers did not show any chiral recognition. In contrast, the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit as chiral barriers was found to show excellent chiral recognition especially for the two enantiomers of a-amino N-propylamides. Some of a-amino methyl esters and α-amino N,N-diethylamides were also resolved on the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit. From these results it was concluded that the two chiral units composing the diastereomeric CSPs can show "matched" or "mismatched" effect on the chiral recognition according to their absolute stereochemistry.
Synthesis and solid-phase application of suitably protected γ-hydroxyvaline building blocks
Cudic, Mare,Mari, Frank,Fields, Gregg B.
, p. 5581 - 5586 (2008/02/09)
(Chemical Equation Presented) Recently, an unexpected modified residue, γ-hydroxy-D-valine (D-Hyv), was identified within ribosomally expressed polypeptide chains of four conopeptides from the venoms of Conus gladiator and Conus mus. To assemble Hyv-conta
Enzymatic removal of carboxyl protecting groups. 1. Cleavage of the tert-butyl moiety
Schmidt, Marlen,Barbayianni, Efrosini,Fotakopoulou, Irene,Hoehne, Matthias,Constantinou-Kokotou, Violetta,Bornscheuer, Uwe T.,Kokotos, George
, p. 3737 - 3740 (2007/10/03)
(Chemical Equation Presented) A recent discovery that a certain amino acid motif (GGG-(A)X-motif) in lipases and esterases determines their activity toward tertiary alcohols prompted us to investigate the use of these biocatalysts in the mild and selective removal of tert-butyl protecting groups in amino acid derivatives and related compounds. An esterase from Bacillus subtilis (BsubpNBE) and lipase A from Candida antarctica (CAL-A) were identified as the most active enzymes, which hydrolyzed a range of tert-butyl esters of protected amino acids (e.g., Boc-Tyr-OtBu, Z-GABA-OtBu, Fmoc-GABA-O tBu) in good to high yields and left Boc, Z, and Fmoc-protecting groups intact.