42- Thiazoline ring, 4-hydroxy— from

As described previously, thiazolines are versatile intermediates to thiazoles. In addition, thiazoline rings are structural motifs found in numerous natural products. Among a variety of methods for the construction of thiazolines, the cyclodehydration protocol is perhaps most popular. Bis(2-methoxyethyl)aminosulfur trifluoride (Deoxo-Fluor) is used as the cyclo-dehydrating agent for the conversion of 3-hydroxy thioamide 60 to the bis(thiazoline) 15 <04H(63)773>. A more recent protocol for the cyclodehydration of P-hydroxy thioamides to thiazolines involves pyridine-buffered phosphorus oxychloride as exemplified by the formation of 62 from 61 <04JA12897>. 

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