合成路线1

This compound can be obtained by two related ways: 1) The cyclization of 3-cyclohexylpropionitrile (I) with thiosemicarbazide (II) by means of trifluoroacetic acid gives 5-(2-cyclohexylethyl)-1,3,4-thiadiazol-2-amino (III), which is submitted to a new cyclization process with bis(2,4,6-trichlorophenyl)malonate (IV) in refluxing xylene yielding 2-(2-cyclohexylethyl)-7-hydroxy-5H-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one (V) (1-3). The nitration of (V) with fuming nitric acid in acetic acid affords the corresponding 7-hydroxy-6-nitro derivative (VI), which is treated with POCl3 and tripropylamine to afford the 7-chloro-6-nitro derivative (VII). The reaction of (VII) with concentrated aqueous NH4OH in ethanol gives the corresponding 7-amino-6-nitro compound (VIII), which is reduced with Sn-HCl in dioxane-water to afford the 6,7-diamino derivative (IX). Finally, this compound is dissolved in aqueous HCl and treated with NaNO2. 2) The cyclization of 3-cyclohexylpropionic acid (X) with thiosemicarbazide (II) by means of hot H2SO4 gives the thiadiazole (III), which is cyclized again with malonic acid (XI) by means of POCl3 in hot toluene to afford the previously obtained thiadiazolopyrimidine (V).