The reaction of 2-amino-2-thiazoline (1) with acetylene carboxylates (2) afforded 5- substituted 2, 3-dihydro-7H-thiazolo [3, 2-a] pyrimidin-7-ones (3). 7-Bromomethyl-2, 3- dihydro-5H-thiazolo [3, 2-a] pyrimidin-5-one (10) was obtained by the reaction of 1 with γ- bromoacetoacetyl bromide. Treatment of 10 with N-bromosuccinimide provided the 6-bromo compound (12). The 7-bromomethyl compounds (10 and 12) were converted to 7- ...