Chemoselective N-acylation of indoles using thioesters as acyl source

The selective acylation of indoles often requires sensitive and reactive acyl chloride derivatives. Here, we report a mild, efficient, functional group tolerant, and highly chemoselective N-acylation of indoles using thioesters as a stable acyl source. A series of indoleamides have been obtained with moderate to good yields. In addition, heterocycles, such as carbazole, can also be used as nucleophiles in this reaction.

An Efficient Protocol for the Synthesis of pyrazolo[1,5-c]quinazolines via Staudinger-Aza-Wittig-Dehydroaromatization Sequence

One-pot synthesis of azide-substituted dihydropyrazoles in isopropanol was performed using chalcones, hydrazine hydrate, and acyl chloride at 0℃, and its subsequent Staudinger-aza-Wittig-dehydroaromatization reactions with methyldiphenylphosphine were also investigated for further application in the construction of pyrazolo[1,5-c]quinazolines.

Modification of the Acyl Chloride Quench-Labeling Method for Counting Active Sites in Catalytic Olefin Polymerization

The reliable and efficient counting of active sites in catalytic olefin polymerization has been realized by using acyl chloride as the quench-labeling agent. However, the molar ratio of acyl chloride to the alkylaluminum cocatalyst must be larger than 1 in order to completely depress side reactions between the quencher and Al-polymeryl that is formed via chain transfer reaction. In this work, a tetrahydrofuran/thiophene-2-carbonyl chloride (THF/TPCC) mixture was used as the quenching agent when counting the active sites of propylene polymerization catalyzed by MgCl2/Di/TiCl4 (Di = internal electron donor)-type Ziegler–Natta catalyst activated with triethylaluminum (TEA). When the THF/TEA molar ratio was 1 and the TPCC/TEA molar ratio was smaller than 1, the [S]/[Ti] ratio of the polymer quenched with the THF/TPCC mixture was the same as that quenched with only TPCC at TPCC/TEA > 1, indicating quench-labeling of all active sites bearing a propagation chain. The replacement of a part of the TPCC with THF did not influence the precision of active site counting by the acyl chloride quench-labeling method, but it effectively reduced the amount of acyl chloride. This modification to the acyl chloride quench-labeling method significantly reduced the amount of precious acyl chloride quencher and brought the benefit of simplifying polymer purification procedures after the quenching step.

Preparation of Thin-Film Composite Nanofiltration Membranes Doped with N- and Cl-Functionalized Graphene Oxide for Water Desalination

In the present work, chemically modified graphene oxide (GO) was incorporated as a crosslinking agent into thin-film composite (TFC) nanofiltration (NF) membranes for water desalination applications, which were prepared by the interfacial polymerization (IP) method, where the monomers were piperazine (PIP) and trimesoyl chloride (TMC). GO was functionalized with monomer-containing groups to promote covalent interactions with the polymeric film. The composite GO/polyamide (PA) was prepared by incorporating amine and acyl chloride groups into the structure of GO and then adding these chemical modified nanomaterial during IP. The effect of functionalized GO on membrane properties and performance was investigated. Chemical composition and surface morphology of the prepared GO and membranes were analyzed by thermogravimetric analysis (TGA), Raman spectroscopy, FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The fabricated composite membranes exhibited a significant increase in permeance (from 1.12 to 1.93 L m−2 h−1 bar−1) and salt rejection for Na2SO4 (from 95.9 to 98.9%) and NaCl (from 46.2 to 61.7%) at 2000 ppm, when compared to non-modified membranes. The amine- and acyl chloride-functionalized GO showed improved dispersibility in the respective phase.

Structure Modifications of Pinostrobin from Temu Kunci (Boesenbergia pandurata ROXB. SCHLECHT) and Their Analgesic Activity Based on in Silico Studies

Temu kunci (Boesenbergia pandurata ROXB. SCHLECHT) is one of Indonesia medicinal plants which contains essential oils and flavonoids and it has interesting pharmacological activities, such as antifungal, antibacterial, antioxidant, anti-inflammatory and anti-cancer. It also contains pinostrobin which potent as anti-inflammatory and analgesic activities through inhibition of COX-2 enzymes. This research was to obtain pinostrobin derivatives of acylation reactions between pinostrobin and acyl chloride derivatives. The structure modifications of pinostrobin were obtained by Schotten-Baumann method through nucleophilic substitution reactions between pinostrobin and acyl chloride derivatives. Their structure had analyzed using the spectrophotometric analysis (NMR, IR, and GC/MS). The investigation of structure modifications of pinostrobin (1) from this plant has demonstrated the presence of pinostrobin acetate (2) and new pinostrobin propionate (3). The 2 and 3 are derivatives of pinostrobin that can be synthesized using the Schotten-Baumann method to yield 84.3% and 73.9%, respectively. The results of in silico study between pinostrobin and pinostrobin acyl derivatives on the COX-2 receptor with a PDB code: 1PXX showed that pinostrobin RS value was -87.18kcal/mol, while pinostrobin propionate had a RS value of -98.61 kcal/mol. It can be predicted that the pinostrobin acyl derivative has greater analgesic activity than pinostrobin, so it is feasible to be developed and carried out research on its analgesic activity in vivo.

The facile and efficient synthesis of novel monocyclic cis-β-lactams conjugates having 1-methyl-1H-imidazole-2-thio nucleus

In this paper, the facile and efficient synthesis of novel monocyclic cis-β-lactam conjugates having 1-methyl-1H-imidazole-2-thiol nucleus has been developed through ketene-imine [2+2] cyclo-addition reaction of acyl chloride and different Schiff’s...

Vapour phase interfacial polymerization: a method to synthesize thin film composite membranes without using organic solvents

Thin film composite membranes (TFC) of polyamide (PA) prepared by interfacial polymerization (IP) between a diamine and an acyl chloride are those applied to industrial nanofiltration and reverse osmosis. Water,...