| Abstract
| - Appropriately substituted2,3-dihydro-7H-thiazolo[3,2-a]pyrimidin-7-ones9−12 and 18 wereconsidered as annulated analogues of HEPT(1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine), and some of these compounds were also found active againstHIV-1, the most activeone being2,3-dihydro-5-[(3,5-dimethylphenyl)methyl]-3-ethoxy-6-ethyl-7H-thiazolo[3,2-a]pyrimidin-7-one (10b). S-Alkylation of5-alkyl-6-(arylmethyl)-2-thiouracils 1−4 wasperformedwith 2-bromoacetaldehyde acetals to furnish theS-[bis(alkoxy)ethyl] derivatives5−8 and withallyl bromide to furnish S-allyl derivatives 17.The target compounds 9−12 were obtainedbyan N regioselective intramolecular cyclizationreaction of silylated 5−8 usingtrimethylsilyltrifluoromethanesulfonate (TMS triflate) as the catalyst.Treatment of the S-allyl derivatives17 with bromine in dry methylene chloride afforded the3-(bromomethyl) derivatives 18.
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