TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The organic solvent is distilled off and replaced with toluene. The purification process further comprises conversion of (III) to (II). The conversion of (II) is achieved using an alkali metal hydroxide. The conversion step is carried out in a mixture of methanol and water. Preferred Components: The crystalline forms A and B of (I) has an X-ray powder diffraction (XRPD) pattern as given in the figure of specification, with peaks value as given in the specification. The crystalline forms A and B of (I) has a thermo gravimetric analysis (TGA) thermogram showing a weight loss with an onset temperature of 259 degrees C plus minus 5 degrees C. The crystalline forms A and B of (I) and amorphous form of (I) has a TGA thermogram as given in the figure of specification. The crystalline forms A and B of (I) has a differential scanning calorimetry (DSC) thermogram showing an endothermic peak with an onset temperature as given in the specification. The crystalline forms A and B of (I) and amorphous form of (I) has DSC thermogram as given in the figure of specification. The crystalline form B of (I) comprises 0.1-0.2 (preferably 0.13) moles of ethyl acetate. The crystalline forms B of (I) has a TGA thermogram showing a weight loss with an onset temperature of 257 degrees C plus minus 5 degrees C and weight loss around 130-200 degrees C. The crystalline forms B of (I) has 1H NMR spectrum comprises peaks attributable to ethyl acetate, where the peaks are at around 4 (preferably 1.2) ppm. The crystalline form B of (I) has a 1H NMR spectrum as given in the figure of specification. The amorphous form of (I) has a TGA thermogram showing a weight loss with an onset temperature of 258 degrees C plus minus 5 degrees C, and around 1.2 wt.% loss of 26-71 degrees C. The amorphous form of (I) has a cycling differential scanning calorimetry (Cycling DSC) thermogram showing a step change due to a glass transition, where the step change is at a temperature of 50 degrees C plus minus 2 degrees C. The organic solvent is a mixture of toluene and methanol. The toluene and methanol are present at a weight proportion of 62:38. The alkali metal hydroxide is sodium hydroxide. The purity of (II) is at least 95%, preferably greater than 99%. ACTIVITY - Tranquilizer; Antimigraine; Cardiovascular-Gen.; Hypotensive; Cardiant; Antianginal; Antiarrhythmic; Vasotropic.    MECHANISM OF ACTION - Dopamine- beta -hydroxylase inhibitor.    EXAMPLE - (R)-5-(2-Aminoethyl)-1-(6,8-difluorochroman-3-yl)-1H-imidazole-2(3H)-thione (6.23 g) in a mixture of dichloromethane (DCM) (40 ml) and methanol (40 ml) was added to a benzaldehyde suspension (2.230 ml). To the resulting clear solution sodium cyanoborohydride (1.9 g) was added in portions at 20-25 degrees C to avoid intensive foaming and the solution was stirred at 20-25 degrees C for 40 hours. The solution was quenched at 20-25 degrees C with in hydrochloric acid (35 ml), neutralized with 3N sodium hydroxide (35 ml), the mixture was extracted with DCM (200 ml). The organic phase was washed with brine, dried (magnesium sulfate), evaporated to dryness. The oily residue crystallized from 2-propanol (40 ml) at 20-25 degrees c over a week-end. The crystals were collected, washed with 2-propanol, dried to give crude product (5.2 g). Recrystallization from 2-propanol-DCM has not removed all impurities. The resulting mixture was collected, evaporated with silica, applied on a column, eluted with ethyl acetate (EA) in a propotion of 9:1, preferably greater than 4:15, fractions were collected (3.8 g) and re-crystallized from acetonitrile (180 ml) at 190-92 degrees C to give crystalline forms A and B of 1-((3R)-6,8-difluoro-3,4-dmyhydro-2H-1-benzopyran-3-yl)-1,3-dihydro-5-(2-((phenylmethy-amino)ethyl)-2H-imidazole)-2-thione (2.25 g).