Annelation to the Quinazoline Ring. Preparation of Some Substituted 2H-Imidazo- and 2,3-Dihydropyrimido[1,2-c]quinazolines

1996 ◽  
Vol 61 (6) ◽  
pp. 957-961 ◽  
Author(s):  
Katarína Špirková ◽  
Štefan Stankovský
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Amino Acid Esters ◽  
H Nmr ◽  
Acid Esters ◽  
C Nmr

Preparation of some substituted 2H-imidazo[1,2-c]quinazolin-3-ones (2a-2f) and 2,3-dihydropyrimido[1,2-c]quinazolin-4-ones (3a-3c) by reaction of corresponding 3H-quinazoline-4-thiones (1a-1d) with amino acid esters is described. IR, 1H NMR and 13C NMR spectra of the compounds synthesized are presented.

Molecular recognition of chiral porphyrins with amino acid esters

2005 ◽  
Vol 09 (01) ◽  
pp. 7-15
Author(s):  
Wen J. Ruan ◽  
Xiao J. Zhao ◽  
Hua Han ◽  
Jing Nan ◽  
Zhi A. Zhu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Electronic Effect ◽  
Association Constants ◽  
Optically Active ◽  
Amino Acid Esters ◽  
Cd Spectra ◽  
Guest Molecules ◽  
H Nmr ◽  
Tripos Force Field ◽  
Acid Esters

Association constants between α,α,α,β- ZnT (o- BocTyr ) TAPP (1), α,α,α,β- ZnT (o- BocAla )- TAPP (2), and a series of amino acid esters were determined in chloroform by means of titrations monitored by UV-vis spectra. Association constants increased in the order K( AlaOMe ) < K( ValOMe ) < K( LeuOMe ), showing the same preference for the electronic effect of bulky amino acid esters. For the guest SerOMe and ThrOMe , the association constants of two hosts showed different orders; the order of 1 is K( SerOMe ) < K( ThrOMe ), and that of 2 is the reverse. The host 2 shows a D -/ L -selectivity of 6.9 for leucine methyl ester at 293 K in CHCl 3, which is the highest enantioselectivity achieved in our study. The host-guest system was studied by 1 H NMR spectra. On association, every proton experiences a small upfield shift. The intensity of circular dichroism (CD) spectra of 1 in the presence of optically active guests were reduced as compared with that of free 1, while that of 2 with optically active guests was of the induced split type. Molecular modeling of the host-guest systems were studied by simulated annealing on the basis of the Tripos force field. The minimal energies of the complexes were calculated, and the results show that the recognition behavior of hosts 1 and 2 toward amino acid esters is very different. The change of the interaction energy of 2 with guest molecules is larger than that of 1.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

Asymmetric Preparation of anti-β-Hydroxyα-amino Acid Esters

Synfacts ◽  
2006 ◽  
Vol 2006 (12) ◽  
pp. 1253-1253
Author(s):  
Y. Hamada ◽  
K. Makino ◽  
M. Iwasaki
Keyword(s):  
Amino Acid ◽  
Amino Acid Esters ◽  
Acid Esters

Antiviral activity of glycyrrhizic acid conjugates with amino acid esters against Zika virus

2021 ◽  
Vol 294 ◽  
pp. 198290
Author(s):  
Lidia A. Baltina ◽  
Mann-Jen Hour ◽  
Ya-Chi Liu ◽  
Young-Sheng Chang ◽  
Su-Hua Huang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Antiviral Activity ◽  
Zika Virus ◽  
Glycyrrhizic Acid ◽  
Amino Acid Esters ◽  
Acid Esters

Enantioselective Nucleophilic Aromatic Substitution Reaction of Azlactones to Synthesize Quaternary α-Amino Acid Derivatives

Synlett ◽  
2020 ◽  
Author(s):  
Xiaohua Liu ◽  
Yi Li ◽  
Hao Pan ◽  
Wang-Yuren Li ◽  
Xiaoming Feng
Keyword(s):  
Hydrogen Bonding ◽  
Charge Transfer ◽  
Amino Acid ◽  
Substitution Reaction ◽  
Nucleophilic Aromatic Substitution ◽  
Amino Acid Derivatives ◽  
Amino Acid Esters ◽  
Aromatic Substitution ◽  
Charge Transfer Interaction ◽  
Acid Esters

AbstractAn asymmetric organocatalytic nucleophilic aromatic substitution reaction of azlactones with electron-deficient aryls was established. A variety of α-aryl α-alkyl α-amino acid esters and peptides were obtained in decent yields and stereoselectivities. A new bifunctional catalytic mode involving charge-transfer interaction and hydrogen bonding is proposed to explain the enantioselectivity.

ChemInform Abstract: CONVENIENT METHOD FOR THE PREPARATION OF N-CARBONYL-α-AMINO ACID ESTERS

1977 ◽  
Vol 8 (50) ◽  
pp. no-no
Author(s):  
YU. A. DAVIDOVICH ◽  
V. I. BUTAEVA ◽  
O. M. GALKIN ◽  
T. N. SENTSOVA ◽  
S. V. ROGOZHIN
Keyword(s):  
Amino Acid ◽  
Convenient Method ◽  
Amino Acid Esters ◽  
Acid Esters
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