Sulfuric Acid → cis-1,3-Dibenzyl-4-hydroxy-4-(3-ethoxypropyl)-hexahydrothieno[3,4-d]imidazol-2-one

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Reaction Steps

To a Grignard reagent solution prepared from 3-ethoxypropyl bromide (41.7 g), magnesium metal (shoot, 11.2 g) and iodine (0.2 g) in 110 ml of anhydrous ether and 30 ml of anhydrous benzene, a solution of cis-1,3-dibenzyl-hexahydrothieno[3,4-d]imidazole-2,4-dione ([α]D20 + 91°, 60.0 g) in 700 ml of anhydrous benzene is added with stirring for two and half hours at 25° to 40°C. The mixture is stirred and refluxed at 68° to 73° C for 5 hours. The reaction mixture is decomposed by the addition of 3N sulfuric acid (280 g) below 20°C. The organic layer is washed with water and concentrated in vacuo to give the residual oil of 76 g of cis-1,3-dibenzyl-4-hydroxy-4-(3-ethoxypropyl)-hexahydrothieno[3,4-d]imidazol-2-one. [α]D20 + 17° (C = 1 in CHCl3). IR (Nujol) 3350 cm-1 (OH); 1690 cm-1 (C = O).

Provenance & Evidence