Letters in Organic Chemistry - Volume 17, Issue 2, 2020

Maltodextrins have an increasing number of biomedical and industrial applications due to their attractive physicochemical properties such as biodegradability and biocompatibility. Herein, we describe the development of a synthetic pathway and characterization of thiol-responsive maltodextrin conjugates with dithiomaleimide linkages. 19F NMR studies were also conducted to demonstrate the exchange dynamics of Read More

Di(2-ethylhexyl) phthalate (DEHP) is the most common phthalate ester, which has been used as a plasticizer for the production of numerous polymers, particularly polyvinyl chloride (PVC). Many other groups have synthesized meso-DEHP indicating interest in this molecule, but we are the first to synthesize enantiomerically pure di[(R)-2-ethylhexyl] phthalate. We report herein, for the first time, the isolation - from the cultur Read More

A novel bis-indole alkaloid was isolated from the flowers of Rauvolfia Yunnanensis Tsiang. Its structure was elucidated as 10,11´- dimethoxy-11,10´-bis-[N(a)-methyl deacetyldeformyl- 1,2- dihydro akuammiline(2β)] (1) on the basis of spectroscopic analysis, including 1D and 2D NMR techniques as well as HRESI-MS and comparison with data from the literature. The bis-indole alkaloid displayed more potent antihypertension activit Read More

Calix[4]monoquinone (3) has been synthesized by oxidation of rigid cone conformation of tripropoxy calix[4]arene (2), and conformational characteristics of this molecule have been studied by means of dynamic nuclear magnetic resonance (DNMR) and HH- correlated nuclear magnetic resonance spectroscopy (HH-COSY NMR). On the basis of the data that have been obtained, free Gibbs energy of activation (ΔG#) for q Read More

Titanium ethoxide has been employed as a novel and efficient reagent for the Knoevenagel condensation of aldehydes with active methylenes such as diethyl malonate and ethyl cyanoacetate under solvent free conditions to afford substituted olefins in high to excellent yields. The reaction is suitable for a variety of aromatic, aliphatic and heteroaromatic aldehydes with various active methylenes. Parallel to this, microwave irr Read More

Hypoxylon sp. was used to ferment at 25°C for 45 days. The solid culture of Hypoxylon sp. was extracted with 75% EtOH under ultrasonic for twice. And the dried combined extracts were then suspended in H2O and partitioned with ethyl acetate. EtOAc extracts were subjected to a silica gel column and eluted with petroleum ether - acetone to afford seven fractions. Sephadex LH-20 and RPHPLC were used subsequently to yi Read More

The aim of the current article was to describe simple procedures for the synthesis of new heterocycles incorporating the quinoxaline moiety using benzene-1,2-diamine and quinoxaline-2,3- dithiol as precursors. Simple synthetic methods are described for the synthesis of new heterocycles using commercially available chemicals. Also, the new compounds were determined using analytical and spectroscopic methods includin Read More

A K2CO3 promoted efficient one pot two-step method for the preparation of 1H-imidazol-4- yl-1-amine derivatives has been developed. A series of second amines with an imidazole group were obtained with 56%-91% yields by the K2CO3 promoted amination of acetates and nitrogen deprotection of the imidazole process.

Oxadiazoles are an important class of heterocyclic compounds, having broad-spectrum activity. They were also reported as anticancer, and antioxidant agents, hence it is of significant importance to explore new oxadiazoles. A series of eleven (5-aryl-N-[4-(trifluoromethyl)phenyl]-1,3,4- oxadiazol-2-amines (6a-k) was synthesized based on the structures of reported compounds, SU-101, IMC38525, and FTAB. All these oxa Read More

The present study deals with the synthesis of novel 1-(1,3-benzothiazol-2-yl)-3-chloro-4Hspiro[ azetidine-2,3'-indole]-2',4(1'H)-dione derivatives from the reaction of 3-(1,3-benzothiazol-2- ylimino)-1,3-dihydro-2H-indol-2-one derivatives with chloroacetyl chloride in the presence of triethylamine (TEA). The mechanism involved simple acid or base catalysed reaction through the formation of Schiff base followed by cyclisation via k Read More

A series of novel 2-S-, 4-, 5-substituted and bicyclic 6-methylpyrimidine-4-ol derivatives including pyrazole, 1,2,4-triazole and pyridazine moieties in the molecule were synthesized by accessible and efficient methods. Thiopyrazolyl derivatives were obtained from 2-mercapto-6-methylpyrimidin-4-ol. 4-Triazolyl and 4-aminotriazolylpyrimidines were synthesized from the quaternary ammonium salt of pyrimidine and 4-chloro-substitu Read More

We have developed an efficient and green synthesis of quinoline derivatives using L-proline under Knoevenagel condensation. L-proline was found to be an efficient catalyst for the Knoevenagel condensation of substituted 2-aminoaryl ketones 1 with the active methylene compounds 2, affording quinolone derivatives 3. The reaction has been done under conventional as well as under microwave conditions. The latter pro Read More