Ethylenethiourea → 5-[2-[(4,5-dihydro-1H-imidazol-2-yl)thio]ethyl]-1,4-dimethylpyrimido[1,6-a]indole

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Reaction Steps

A mixture of 2-imidazolidinethione (3.1 g), 5-(2-bromoethyl)-1,4-dimethylpyrimido[1,6-a]indole (6 g, described in Example 13) and dry dioxane (400 ml) is refluxed for 6 hours. The resulting precipitate is collected by filtration and dissolved in water and the solution is neutralized with aqueous sodium bicarbonate. After adding a few drops of 10% sodium hydroxide, the aqueous mixture is extracted with chloroform. The combined extracts are washed with water, dried over magnesium sulfate, filtered and evaporated. The residue is crystallized from acetonitrile to obtain the title compound (3.8 g): mp 157°-159° C.; ir (CHCl3) 3400, 1610, 1595 and 1570 cm-1 ; uv(MeOH) λmax 250,299,311 and 325 nm; ε=35200, 4840, 8200, and 10870, respectively; and nmr (CDCl3) δ2.52(s), 2.99(s), 3.43(m), 3.60(s), 4.25(s) and 7.1-8.2(m).

Provenance & Evidence