nhong Jia

A general, simple and green process to access pyrrolo[2,1-a]isoquinolines using a KI/TBHP catalytic system

A novel KI/TBHP-catalyzed 1,3-dipolar cycloaddition/oxidation/aromatization cascade reaction provided general, efficient and green access to biologically important pyrrolo[2,1-a]isoquinolines. The product pyrrolo[2,1-a]isoquinolines were obtained from reactions between simple, readily available dipolarophiles and tetrahydroisoquinolines in moderate to excellent yields The reaction was environmentally benign in the adoption of nontoxic KI as a catalyst and IOH was generated in situ from the oxidation reaction of KI and TBHP.

High quantum yield and pH sensitive fluorescence dyes based on coumarin derivatives: fluorescence characteristics and theoretical study

The fluorescence coumarin derivatives were synthesized by an efficient one-pot, three-component reaction in 80–90% yields. These fluorescence dyes exhibited high fluorescent intensity and quantum yield where compound 4e, with p-methyl substituted on the phenyl ring, had the maximum fluorescence intensity and also the fluorescence quantum yield reached 0.83. These coumarin derivatives display different fluorescence in acidity and alkaline conditions and the fluorescent colour changed from blue to yellow-green when the pH of the solution turned from acidic to alkaline. The pH sensitive fluorescence properties of the coumarin derivatives showed a large shift from 441 to 538 nm in wavelength. Experimental results were confirmed with DFT and TDDFT calculations.

Copper-catalyzed cascade reactions of N-(2-bromoallyl)amines with KHCO3 as the C1 source: an efficient process for the synthesis of oxazolidin-2-ones

A novel synthesis of oxazolidin-2-ones by carbamic acid formation and a subsequent copper-catalyzed intramolecular vinylation from N-(2-bromoallyl)amines and KHCO3 was developed. KHCO3 was used as a C1 source and base in this efficient and convenient cascade process.

Iodine mediated reaction of quinones and N-substituted amino esters to 2-substituted benzo[f]isoindole-4,9-diones

A novel and efficient synthesis of benzo[f]isoindole-4,9-diones through the I2-promoted cyclization reaction of N-substituted amino acid esters and quinones has been realized successfully via an unprecedented 1,3-dipolar cycloaddition using KF as the base. Different substituted amino esters were found able to react with quinones through a cycloaddition reaction to afford 2-substituted benzo[f]isoindole-4,9-diones. The unexpected, short, attractive and direct synthesis of these interesting compounds is important and relevant, and provides an extremely preferable method for the synthesis of 2-substituted benzo[f]isoindole-4,9-diones.

X-ray structure of 1,3,4-tri-O-acetyl-2-deoxy-β-d-erythro-pentopyranose

Peracetylated 2-deoxy-d-erythro-pentose (2-deoxy-d-ribose) was synthesized through the acetylation of 2-deoxy-d-ribose with acetic anhydride in pyridine, and the products (including all four ring forms) exist in form of either a white solid or a syrup. A single crystal of 1,3,4-tri-O-acetyl-2-deoxy-beta-d-erythro-pentopyranose was obtained from the syrup and its structure was determined by X-ray diffraction. The crystal adopts the (1)C(4) conformation, presenting an orthorhombic system, space group P2(1)2(1)2(1) with Z=4, unit cell dimensions a=7.2274 (3)A, b=8.0938 (5)A, and c=22.0517 (11)A.