Zhi-Ping Lin

An improved synthesis of 1,3,5-triaryl-2-pyrazolines in acetic acid aqueous solution under ultrasound irradiation

Background Pyrazoline derivatives have been found to possess a broad spectrum of biological activities. Among various pyrazoline derivatives, 2-pyrazolines seem to be the most frequently studied. A variety of methods have been reported for the preparation of this class of compound. However, in spite of their potential utility, some of the reported methods suffer from drawbacks such as long reaction times, cumbersome product isolation procedures and environmental concerns. Organic reactions in aqueous media have attracted increasing interest recently because of environmental issues and the understanding of biochemical processes. Ultrasound has increasingly been used in organic synthesis in the last three decades. A large number of organic reactions can be carried out in higher yields, shorter reaction time or milder conditions under ultrasound irradiation. Results Preparation of a series of 1,3,5-triaryl-2-pyrazolines through the reaction of chalcones and phenylhydrazine hydrochloride was carried out in 83–96% yield within 1.5–2 h in sodium acetate-acetic acid aqueous solution under ultrasound irradiation. Conclusion We have described a practical and convenient procedure for the synthesis of 1,3,5-triaryl-2-pyrazolines in sodium acetate-acetic acid aqueous solution at room temperature under ultrasound irradiation.

One‐Pot Synthesis of 4‐Oxo‐2‐thioxohexahydropyrimidines Catalyzed by Potassium Carbonate Under Ultrasound

Abstract The one‐pot condensation of aldehydes, ethyl cyanoacetate and thiourea catalyzed by potassium carbonate in ethanol results 4‐oxo‐2‐thioxohexahydropyrimidines in 20–90% yields under ultrasound irradiation.

Pinacol Coupling of Aromatic Aldehydes and Ketones Using TiCl3‐Al‐EtOH Under Ultrasound Irradiation

Abstract Titanium trichloride in EtOH can be reduced by Al to the corresponding low‐valent titanium complexes. This can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 40–82% yields within 30–90 min at r.t. under ultrasound irradiation.

Magnesium‐Induced Pinacol Coupling of Aromatic Aldehydes and Ketones Under Ultrasound Irradiation

Abstract The system of magnesium and magnesium iodide can reduce some aromatic aldehydes and ketones to the corresponding pinacols in good yields within 10–60 min at room temperature under ultrasound irradiation.

Simple and Efficient Synthesis of 3-(N-Hydroxylamino)-1,3-diarylpropan-1-one Oximes Under Ultrasound Irradiation

Abstract A series of 3-(N-hydroxylamino)-1,3-diarylpropan-1-one oximes have been synthesized through the reaction of chalcones and hydroxylamine hydrochloride in 56–96% yield within 2–3 h in the presence of sodium acetate in EtOH under ultrasound irradiation.

Pinacol Coupling of Aromatic Aldehydes using La-Ticl4 in CH3COOEt under Ultrasound Irradiation

Titanium tetrachloride can be reduced by lanthanum filings to the corresponding low valent titanium complex, which can induce some aromatic aldehydes to the corresponding pinacols in 28%-97% yields within 10-50 min in ethyl acetate at r.t. under ultrasound irradiation.