DTBP-promoted site-selective α-alkoxyl C–H functionalization of alkyl esters: synthesis of 2-alkyl ester substituted chromanones

ABSTRACTChalcogenide semiconductors have been deposited epitaxially from aqueous solutions either chemically or electrochemically at growth rates of up to 0.7 μmhr−1. After recalling the basic principles of these deposition processes, results are presented concerning chemically deposited CdS on InP, GaP and CuInSe2 substrates, electrodeposited CdTe on InP, and CdSAnP heterostructures. Characterisation of these structures by RHEED, TEM, HRTEM, and glazing angle X ray diffraction allows to analyse the effects of substrate orientation, polarity, lattice match plus the influence of temperature on epitaxial growth. These results are discussed in terms of self organisation and a site selective growth mechanisms due to the free enegy of formation of each compound.

Download Full-text

ACTIVATION OF THE TRANSESTERIFICATIONS PROCESS OF VEGETABLE OILS TRIGLYCERIDES WITH METHANOL UNDER THE INFLUENCE OF MAGNETIC FIELD

JOURNAL OF ADVANCES IN CHEMISTRY ◽

10.24297/jac.v11i6.850 ◽

2015 ◽

Vol 11 (6) ◽

pp. 3630-3634

Author(s):

T.A. Mamedova ◽

Z.M. Aliyeva ◽

A.E. Aliyeva ◽

R.T. Samedov ◽

V.M. Abbasov ◽

...

Keyword(s):

Magnetic Field ◽

Fatty Acids ◽

Reaction Time ◽

Vegetable Oils ◽

High Yield ◽

Alkyl Esters ◽

Sunflower Oils ◽

The Magnetic Field

The process of producing mono-alkyl esters of fatty acids from cottonseed and sunflower oils under the influence of the magnetic field with intensity 15-45 mT was investigated . It was revealed that the use of the energy of magnetic field allows to reduce the reaction time to 10 times, the excess of used alcohol to 2 times while maintaining high yield of the desired product.

Download Full-text

para-Selective Cyanation of Arenes by H-Bonded Template

10.26434/chemrxiv.11448690.v1 ◽

2019 ◽

Author(s):

Sandeep Pimparkar ◽

Trisha Bhattacharya ◽

Arun Maji ◽

Argha Saha ◽

Ramasamy Jayarajan ◽

...

Keyword(s):

Selective Functionalization ◽

Directing Group ◽

Product Utility ◽

Site Selective

The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work we demonstrate the para-selective introduction of versatile nitrile moiety, enabled by detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias. The conspicuous shift in the step energetics was probed by both experimental and computational mechanistic tools heralds the inception of para-deuteration. The synthetic impact of the methodology was highlighted with reusability of directing group and post synthetic modifications

Download Full-text

para-Selective Cyanation of Arenes by H-Bonded Template

10.26434/chemrxiv.11448690 ◽

2019 ◽

Author(s):

Sandeep Pimparkar ◽

Trisha Bhattacharya ◽

Arun Maji ◽

Argha Saha ◽

Ramasamy Jayarajan ◽

...

Keyword(s):

Selective Functionalization ◽

Directing Group ◽

Product Utility ◽

Site Selective

The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work we demonstrate the para-selective introduction of versatile nitrile moiety, enabled by detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias. The conspicuous shift in the step energetics was probed by both experimental and computational mechanistic tools heralds the inception of para-deuteration. The synthetic impact of the methodology was highlighted with reusability of directing group and post synthetic modifications

Download Full-text

Cobalt/Lewis Acid Catalysis for Hydrocarbofunctionalization of Alkynes via Cooperative C–H Activation

10.26434/chemrxiv.11760519.v1 ◽

2020 ◽

Author(s):

Chang-Sheng Wang ◽

Sabrina Monaco ◽

Anh Ngoc Thai ◽

Md. Shafiqur Rahman ◽

Chen Wang ◽

...

Keyword(s):

Catalytic System ◽

Lewis Acid ◽

Hydrogen Transfer ◽

Acid Catalysis ◽

Rate Limiting Step ◽

Site Selectivity ◽

Set Up ◽

Site Selective ◽

First Time ◽

Rate Limiting

A catalytic system comprised of a cobalt-diphosphine complex and a Lewis acid (LA) such as AlMe3 has been found to promote hydrocarbofunctionalization reactions of alkynes with Lewis basic and electron-deficient substrates such as formamides, pyridones, pyridines, and azole derivatives through site-selective C-H activation. Compared with known Ni/LA catalytic system for analogous transformations, the present catalytic system not only feature convenient set up using inexpensive and bench-stable precatalyst and ligand such as Co(acac)3 and 1,3-bis(diphenylphosphino)propane (dppp), but also display distinct site-selectivity toward C-H activation of pyridone and pyridine derivatives. In particular, a completely C4-selective alkenylation of pyridine has been achieved for the first time. Mechanistic stidies including DFT calculations on the Co/Al-catalyzed addition of formamide to alkyne have suggested that the reaction involves cleavage of the carbamoyl C-H bond as the rate-limiting step, which proceeds through a ligand-to-ligand hydrogen transfer (LLHT) mechanism leading to an alkyl(carbamoyl)cobalt intermediate.

Download Full-text