Boron tribromide mediated debenzylation of benzylamino and benzyloxy groups

The treatment of 2(or 4)-benzylamino substituted quinolines, 9-benzylaminoacridine, 2-benzylaminopyridine, a 4-benzyloxyquinoline, and an N-benzyloxyamidine with BBr₃ yields the corresponding amino or hydroxy substituted compounds. The scope and limitations of this novel reaction are discussed.     

Synthesis of 7‐Alkoxy/Hydroxy‐α‐methyltryptamines

Abstract

A simple method for the preparation of 7‐alkoxy/hydroxy‐α‐methyl‐DL‐tryptamines is reported. The key steps of the synthesis are the Japp–Klingemann coupling of 2‐piperidone‐3‐carboxylic acid 3 with diazonium salts 4, the Fischer‐type cyclization of hydrazones 5 to β‐carboline derivatives 6 and their hydrolysis to title compounds 8.     

Synthesis and characterization of new polyfluorinated dendrimeric phthalocyanines

The synthesis of new polyfluorinated dendrimeric metallophthalocyanines (M = Zn, Ni, Co) bearing 3,5-bis(2′,3′,4′,5′,6′-pentafluorobenzyloxy)benzyloxy moieties (2–4) was achieved by cyclotetramerization of phthalonitrile derivative 1 in the presence of zinc, nickel or cobalt salts in DMF. All the target phthalocyanines were separated by column chromatography and their spectroscopic, fluorescence and energy transfer properties, and aggregation behavior were investigated in different solvents and at different concentrations in chloroform. The compounds were characterized by Fourier transform-infrared, fluorine, proton and carbon nuclear magnetic resonance, mass, ultraviolet–visible and fluorescence spectral data. The phthalocyanines (2–4) were extremely soluble in various organic solvents, such as tetrahydrofuran, acetone and dichloromethane.     

Ultrasound assisted arylation of benzyl alcohol with 4-nitrochlorobenzene under a new multi-site phase-transfer catalyst in solid–liquid condition

The ultrasound assisted preparation of 1-(benzyloxy)-4-nitrobenzene from the reaction of 4-chloronitrobenzene (CNB) and benzyl alcohol was carried out successfully using potassium hydroxide and catalyzed by a new multi-site phase-transfer catalyst (MPTC) viz., 1,3,5-triethyl-1,3,5-trihexyl-1,3,5-triazinane-1,3,5-triium trichloride in a solid–liquid reaction condition (SL-MPTC). The advantage of using SL-MPTC is to avoid a serious hydration of potassium salt of benzyl alcohol in the reaction between 4-chloronitrobenzene (CNB) and benzyl alcohol. The reaction is greatly enhanced in the solid–liquid system, catalyzed by multi-site quaternary ammonium salt (MPTC) and ultrasound irradiation (40 kHz, 300 W) in a batch reactor, it shows that the overall reaction greatly enhanced with ultrasound irradiation than without ultrasound. The reaction mechanism is proposed and verified by examining the experimental evidence. A kinetic model is proposed in which a pseudo first-order rate law is sufficient to describe the results, such as the effects of agitation speed, ultrasound, different phase transfer catalysts and the effect of organic solvents, the amount of newly prepared MPTC, the effect of temperature, the amount of water, the concentration of 4-chloronitrobenzene (CNB) and potassium hydroxide concentrations. The apparent rate constant (k_app) were investigated in detail. Rational explanations to account for the phenomena on the results were made.