One‐Step Synthesis of 2‐Aminothiazoline Derivatives Free of Lachrymatory Intermediates

Abstract

A convenient one‐step condensation of p‐R‐acetophenones, dioxane dibromide, and N,N′ dialkylthioureas was developed as a synthetic access to derivatives of 2‐amino‐1,3‐thiazoline, such as N‐[4‐(4‐R‐phenyl)‐3‐R1‐2,3‐dihydro‐1,3‐thiazol‐2‐yliden]‐N‐(R1)amine, where R=H, Br, NO₂, or CH₃O, and R1=CH₃, CH₃CH₂, CH₃CH₂CH₂CH₂, or Ph. Unlike the routine syntheses of similar compounds based on lachrymatory ω‐halogenated acetophenones, the one‐step approach escapes the preparation and dealing with inconvenient starting materials. The yields based on the starting p‐R‐acetophenones were in the range of 57–70%.

Keywords:

• 2‐Amino 1,3‐thiazoline
• condensation
• cyclization
• synthesis

Acknowledgment

The support of this study by Johnson & Johnson Pharmaceutical Research and Development, a division of Janssen Pharmaceutica N.V., which contracted the new products for pharmacological evaluations, is gratefully acknowledged.