scholarly journals Investigation of Substituent Effect in Modified Nature-Sourced Polymers: Rational Side Chain Engineering to Control Yield, Design, and Properties

ACS Omega ◽  
2018 ◽  
Vol 3 (10) ◽  
pp. 12841-12850 ◽  
Author(s):  
Roi Rutenberg ◽  
Gilad Golden ◽  
Yael Cohen ◽  
Maya Kleiman ◽  
Elena Poverenov
Keyword(s):  
Substituent Effect ◽  
Side Chain ◽  
Rational Side

Polar effects on 13C NMR chemical shifts and rotational barriers of amides. A dual substituent parameters analysis of N,N-dimethyl-3-(5-substituted-2-furyl)-acrylamides

1987 ◽  
Vol 52 (2) ◽  
pp. 409-424 ◽  
Author(s):  
Zdeněk Friedl ◽  
Stanislav Böhm ◽  
Igor Goljer ◽  
Anna Piklerová ◽  
Daniela Poórová ◽  
...  
Keyword(s):  
Substituent Effect ◽  
Chemical Shifts ◽  
Polar Effect ◽  
Dominant Factor ◽  
Side Chain ◽  
Nmr Chemical Shifts ◽  
Resonance Effects ◽  
H Nmr ◽  
Reverse Substituent Effect ◽  
C Nmr

13C NMR chemical shifts were measured for sixteen N,N-dimethyl-3-(5-substituted-2-furyl)-acrylamides in CDCl3 at 21 °C; the barriers of rotation about the C-N bond ΔGc° were determined by using the 1H NMR coalescence method, and the positions of the IR bands of the ν(C=O) stretching vibrations were measured. The dual substituent parameters (DSP) analysis of the 13C NMR chemical shifts for atoms of the vinylcarboxamide side chain -C(3)H=C(2)H-C(1)=O(-N) gives evidence that the chemical shifts for the C-1 and C-3 atoms are controlled primarily by polar effects (δ(C-3) = -3.12σI - 1.03σR0; λ = ρI/ρR = 3.0), which exert a reverse substituent effect on these atoms. Similarly, the DSP analysis of the ΔGc° and ν(C=O) data shows that the dominant factor of the total substituent effect is the polar effect (λ = 1.95 and 1.70, respectively). A confrontation of the results of the DSP analysis with the CNDO/2 calculated electron densities at the corresponding atoms demonstrates that the reactivity of the entire vinylcarboxamide side chain can be well explained in terms of a combination of the polar effect (π-electron polarization) with resonance effects.

Unexpected substituent effect by a comonomer unit on the reactivity of an isocyanate group in a copolymer side chain

2005 ◽  
Vol 44 (1) ◽  
pp. 681-685 ◽  
Author(s):  
Yoshiteru Itagaki ◽  
Atsushi Sudo ◽  
Takeshi Endo
Keyword(s):  
Substituent Effect ◽  
Isocyanate Group ◽  
Side Chain

Rational Side-Chain Amino Acid Substitution in Firefly Luciferase for Improved Thermostability

2018 ◽  
Vol 54 (6) ◽  
pp. 584-590
Author(s):  
Q. Xu ◽  
M. Si ◽  
Z. Zhang ◽  
Z. Li ◽  
L. Jiang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Firefly Luciferase ◽  
Side Chain ◽  
Rational Side

Electroluminescent properties of side-chain naphthalimide-derivated polymers

1998 ◽  
Vol 95 (6) ◽  
pp. 1351-1354 ◽  
Author(s):  
C.-M. Bouché ◽  
P. Le Barny ◽  
H. Facoetti ◽  
F. Soyer ◽  
P. Robin
Keyword(s):  
Side Chain

Evidence for Impaired Hepatic Vitamin K1 Metabolism in Patients Treated with N-Methyl-Thiotetrazole Cephalosporins

1984 ◽  
Vol 51 (03) ◽  
pp. 358-361 ◽  
Author(s):  
H Bechtold ◽  
K Andrassy ◽  
E Jähnchen ◽  
J Koderisch ◽  
H Koderisch ◽  
...  
Keyword(s):  
Protein C ◽  
Oral Intake ◽  
Bleeding Complications ◽  
Side Chain ◽  
Acute Administration ◽  
Vitamin K1 ◽  
New Class ◽  
Parenteral Alimentation ◽  
Hepatocellular Regeneration ◽  
Echis Carinatus

SummaryIn 8 patients on no oral intake and with parenteral alimentation, administration of cephalosporins with N-methyl-thiotetrazole side chain (moxalactam, cefamandole), was associated with prolongation of prothrombin time, appearance in the circulation of descarboxy-prothrombin (counter immunoelectrophoresis and echis carinatus assay) and diminution of protein C. Acute administration of 10 mg vitamin Ki was followed by the transient appearance of vitamin K1 2,3-epoxide, indicating an impaired hepatocellular regeneration of vitamin K1 from the epoxide. Impaired hepatic vitamin K1 metabolism, tentatively ascribed to the N-methyl-thiotetrazole group, is one (but possibly not the only) cause of bleeding complications and depression of vitamin K1dependent procoagulants in patients treated with the new class of cephalosporins.

METABOLISM OF 17α-HYDROXYPROGESTERONE-4-14C-17α-CAPROATE BY HOMOGENATES OF RAT LIVER AND HUMAN PLACENTA

1961 ◽  
Vol 36 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Margaret Wiener ◽  
Charles I. Lupa ◽  
E. Jürgen Plotz
Keyword(s):  
Rat Liver ◽  
Human Placenta ◽  
Steric Hindrance ◽  
Placental Tissue ◽  
Caproic Acid ◽  
Major Product ◽  
Side Chain ◽  
Anaerobic Conditions ◽  
Prolonged Action ◽  
Long Acting

ABSTRACT 17α-hydroxyprogesterone-4-14C-17α-caproate (HPC), a long-acting progestational agent, was incubated with homogenates of rat liver and human placenta. The rat liver was found to reduce Ring A of HPC under anaerobic conditions to form allopregnane-3β,17α-diol-20-one-17α-caproate and pregnane-3β,17α-diol-20-one-17α-caproate, the allopregnane isomer being the major product. The caproic acid ester was neither removed nor altered during the incubation. Placental tissue did not attack HPC under conditions where the 20-ketone of progesterone was reduced. It is postulated that this absence of attack on the side chain is due to steric hindrance from the caproate ester, and that this may account for the prolonged action of HPC.

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