Theoretical Insights Elucidate Novel Active Phosphonate Esters—Cephalosporin Antibiotics’ Intermediate

Theoretical insights elucidate a series of active phosphonate esters application in preparation of Cephalosporin antibiotics’ intermediate. The B3LYP/6-311+G(d,p) method was employed to obtain the stable equilibrium geometries including comparing to the AE-active ester. It was found that the Ethyl-aminothiazoly Loximate (AT) molecule fragment is almost planar sheet, but it is almost perpendicular to the plane of phosphoryl ester. Moreover, the calculated Mulliken atomic charge distribution and frontier molecular orbital analysis of these esters showed that the amino N atom connected to the Thiazole ring of the AT had the maximum negative charge, which suggested that this area had high molecular activity. The value of ΔEL-H was energy gap between EHOMO and ELUMO and indicated that compound 6a had high reaction activity. The theory calculation results can explain the reaction mechanism well and predict that the novel active phosphonate ester has a hopeful application prospect in preparation of Cephalosporin antibiotics’ intermediate.

Studies on the Relationship between the Helical Structure and Optical Activity of Some Chiral Cyclic Esters Ⅱ

A method for the analysis of the relationship between the helical structure and optical activity was proposed by the study of the conformations and X-ray diffraction structures of some cyclic esters prepared by esterification of L-(-)-2.3-O-methylidene threitol and L-(+)-2,3-O-isopropplidene threitol with alkanedioyl dichlorides and o-,m-,and p-phthaloyl dichlorides.

Electrochemically promoted decarboxylative borylation of alkyl N-hydroxyphthalimide esters

An electrochemically promoted decarboxylative borylation reaction is reported. The reaction proceeds under mild conditions in an undivided cell without use of transition metal-or photo-catalysts. The key feature of the reaction is the compatibility of diboron reagents with the electrochemical conditions. This reaction exhibits broad substrate scope, good functional group tolerability, and easy scalability.

Synthesis of amyl ester grafted on carbon-nanopolymer composite as an inhibitor for cleaner shale drilling

Wellbore instability in oil and gas industry well drillings is a significant challenge that is linked to shale swelling when shale interacts with free water molecules in the water-based drilling fluid.Strategic design of environmentally benign,biodegradable,and effective shale hydration inhibitors is a prominent objective of contemporary exploration in well-drilling fluids as a replacement for the common KCl which is detrimental to aquatic lives.This work reports the synthesis and potential of novel green acrylic polymer-amyl ester activated carbon(-C)nanocomposite to hinder shale hydration in formations during drilling.Both less hydrophobic acrylic acid-acrylamide-activated carbon-amyl ester(AA-AAm-C-Amyl)and more hydrophobic acrylic acid-acrylamide-octadecene-activated carbon-amyl ester(AA-AAm-OD-CAmyl)composites were synthesized,characterized,and tested with standard methods as a cleaner fluid additive for shale swelling inhibition,and their results compared with that of KCl.The polymer matrixes displayed remarkable thermal stability.Results also indicate that AA-AAm-C-Amyl and AA-AAm-OD-CAmyl composites could stabilize wellbore effectively with 95.2%and 93.7%anti-swelling ratio,and shale recovery capacity of 97%and 95.2%respectively.The surface evaluation of the composite fluidtreated bentonite revealed that the mechanism of inhibition could be based on the collaborative action of nanopore plugging of carbon core and strong adsorption of the polymer component of the materials on clay surfaces via encapsulation and hydrogen bonding to form an impressive filter cake which could actively prevent water invasion into formation.Hence,AA-AAm-C-Amyl and AA-AAm-OD-C-Amyl composites could be a sustainable substitute for the conventional KCl as a shale inhibitor for welldrilling.

Syntheses of New Functionalized Monomers for π-Conjugated Polymers

1 Results Tailored monomers based on the activated esters of 2,5-dibromobenzoic (sulfonic) acid derivatives, the 3-substituted 2,5-dibromothiophenes, the 9-substituted 2,7-dibromocarbazoles, and on the brominated 1,10-phenanthrolines suitable for Suzuki, Yamamoto or Grignard metathesis (GRIM) coupling reactions were synthesized and characterized by melting point, elemental analysis, 1H NMR, FTIR and TLC. The Horner-Wadsworth-Emmons reaction mechanism was utilized for the preparation of the 3-[2-(pyren-1...

Synthesis and Self-Assembly of Two 1,3-Alternate Thiacalix[4]arenes Derivatives Bearing Amide Groups

Two 1,3-alternate thiacalix[4]arene derivatives bearing amide groups, 1,3-alternate p-tert-butylthiacalix[4]arene tetraamide (4), and 1,3-alternate p-H-thiacalix[4]arene tetraamide (6) were prepared, and their crystal structures were determined by single-crystal X-ray diffraction method. The steric hindrances posed by tert-butyl groups play an important part in the synthesis and the self-assembly of the two compounds. Compound 6 was synthesized from the corresponding ester, which was obtained by the reaction of acid chloride with ammonia. In the crystal structure, compound 4 presents a highly symmetric molecular structure, while for compound 6, because of absence of tert-butyl groups, it presents a more flexible molecular structure.