A new and efficient method for the preparation of substituted 3,4-dihydropyrimidin-2(1H)-ones via Biginelli synthesis using catalytic amounts of 1,3-dichloro-5,5-dimethylhydantoin is presented. Short reaction times, easy work-up, high yields of products and stability, easy-handling, non-toxicity and cheapness of the catalyst are noteworthy advantages of the present work.

A simple, facile, and efficient procedure for the synthesis of 2-arylthizolines and 2-arylimidazolines has been developed by the simple condensation of nitriles with 2-aminoethanethiol or ethylenediamine catalyzed by 1,3-dibromo-5,5-dimethylhydantoin under solvent-free conditions. Selective preparation of bisthiozolines and monoimidazolines from dinitriles and also selective conversion of arylnitriles to their corresponding 2-arylthiazolines or imidazolines in the presence of alkylnitriles can be considered as considerable advantages of this method.

The use of a stable, easily available and efficient catalyst in the title reaction is established.

1,3-Dibromo-5,5-dimethylhydantoin as an Efficient Homogeneous Catalyst for the Synthesis of 2-Arylthiazolines and 2-Arylimidazolines. -An inexpensive, approximately non-toxic, commercially available, and highly efficient catalyst, short reactions times, solvent-free conditions, easy work-up and high yields are advantages of the present protocol. -(HOJATI*, S. F.; MOHAMMADPOOR-BALTORK, I.; MALEKI, B.; GHOLIZADEH, M.; SHAFIEZADEH, F.; HAGHDOUST, M.; Can.