Product Class 14: Pyrazines

Yamamoto,; Shinkai,

doi:10.1055/sos-sd-016-00919

Cited by 2 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The result in Figure indicates that the temperature at the inflection point of the curve is 386.15 K (standard uncertainty, 0.5 K), which is the melting point ( T m ) of 2-amino-5-bromopyrazine, and the fusion enthalpy (Δ fus H ) of 2-amino-5-bromopyrazine is 10.01 kJ mol –1 (standard uncertainty, 0.3 kJ mol –1 ). Besides, some previous publications have reported the melting points of 2-amino-5-bromopyrazine. ,,,− The T m value of 2-amino-5-bromopyrazine obtained in this work was similar to the values 387.65–388.65 K, 386.75 K, 386.15–387.15 K, and 385.15–387.15 K ,, in the literature. However, there are no data related to the fusion enthalpy of 2-amino-5-bromopyrazine in the database, so the data measured this time cannot be compared with the literature value.…”

Section: Resultssupporting

confidence: 88%

“…Besides, some previous publications have reported the melting points of 2-amino-5-bromopyrazine. 13,14,16,26−28 The T m value of 2-amino-5-bromopyrazine obtained in this work was similar to the values 387.65−388.65 K, 13 386.75 K, 26 386.15−387.15 K, 16 and 385.15−387.15 K 14,27,28 in the literature. However, there are no data related to the fusion enthalpy of 2-amino-5-bromopyrazine in the database, so the data measured this time cannot be compared with the literature value.…”

Section: Description Of Apparatussupporting

confidence: 86%

See 1 more Smart Citation

Solubility Measurement and Correlation of 2-Amino-5-bromopyrazine in Methanol/Ethanol/Isopropanol/Propylene Glycol Plus Water and 10 Pure Solvents at (278.15–323.15) K

Zhang

Huang

2023

J. Chem. Eng. Data

View full text Add to dashboard Cite

The solubility of 2-amino-5-bromopyrazine in the co-solvent mixtures of methanol, ethanol, isopropanol, and propylene glycol (PG) plus water and 10 monosolvents (methanol, ethanol, isopropanol, N,N-dimethylformamide (DMF), n-propanol, n-butanol, acetone, ethylene glycol (EG), PG, and water) was experimentally measured by the isothermal method at 278.15–323.15 K under 101.2 kPa. The temperature dominated the trend of solubility of 2-amino-5-bromopyrazine in pure and mixed solvents, especially high temperatures had a positive effect on dissolution. For the pure solvent system, the maximum solubility was obtained in DMF. For the mixed systems, isopropanol + water was superior to the other three combinations. The Apelblat model, van’t Hoff model, and NRTL model were used to correlate the solubility of 2-amino-5-bromopyrazine in 10 monosolvents. Furthermore, three thermodynamic co-solvency models including the Jouyban–Acree (JA) model, the Van’t Hoff–Jouyban–Acree (VJA) model, and the modified Apelblat–Jouyban–Acree (AJA) model were used to calculate the solubility data. This study would be helpful to the synthesis and purification processes of the final product.

show abstract

Section: Resultssupporting

confidence: 88%

Section: Description Of Apparatussupporting

confidence: 86%

Solubility Measurement and Correlation of 2-Amino-5-bromopyrazine in Methanol/Ethanol/Isopropanol/Propylene Glycol Plus Water and 10 Pure Solvents at (278.15–323.15) K

Zhang

Huang

2023

J. Chem. Eng. Data

View full text Add to dashboard Cite

show abstract

“…(see Figure ). These pyrasal ligands are more electron-withdrawing due to the pyrazine ring in the backbone, consequently reducing the nitrogen atom electron density available for bonding with a metal center . In preparing cerium pyrasal complexes, it was observed that a judicious choice of cerium(III) salts, specifically the counterion, directly affected the coordination geometry of the complexes formed with salophen ligands, but 8-coordinate complexes were obtained .…”

Section: Introductionmentioning

confidence: 99%

Cerium(IV) Pyrasal Complexes: A pH-Dependent 8- to 10-Coordinate Cerium Chelate Switch

Eralie,

Hoang,

Williamson

et al. 2023

Inorg. Chem.

View full text Add to dashboard Cite

In this work, five cerium(IV) complexes were synthesized, three of which were structural isomorphs from the same pyrasal ligand with the solid-state result identified by structural analysis dependent on the initial pH of the reaction solution and the temperature at which the reaction is performed. The ligands explored here are pyrasal ligands, which are Schiff-base ligands formed by the condensation of 2,3-diaminopyrazine and a salicylaldehyde derivative. Pyrasal ligands have weaker binding than other salophen-type ligands due to the electron-withdrawing effect of the nitrogen atoms contained within the pyrazine ring. The weaker binding leaves the ligand more susceptible to the changes in pH and temperature that alternate the chelating environment from 8-to 10-coordinate. This electron-withdrawing effect of the pyrazine backbone also deactivates the second amine after the first condensation addition of salicylaldehyde. Without a metal to template the complex formation reaction, even with extended reaction times and the addition of a large excess of ligand, the result is the addition of only one salicylaldehyde.

show abstract

Product Class 14: Pyrazines

Cited by 2 publications

References 0 publications

Solubility Measurement and Correlation of 2-Amino-5-bromopyrazine in Methanol/Ethanol/Isopropanol/Propylene Glycol Plus Water and 10 Pure Solvents at (278.15–323.15) K

Solubility Measurement and Correlation of 2-Amino-5-bromopyrazine in Methanol/Ethanol/Isopropanol/Propylene Glycol Plus Water and 10 Pure Solvents at (278.15–323.15) K

Cerium(IV) Pyrasal Complexes: A pH-Dependent 8- to 10-Coordinate Cerium Chelate Switch

Contact Info

Product

Resources

About