Abstract: In the preparation of zolmitriptan of formula III the reduction of the diazonium salt to (5)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one of formula IV is performed in a more concentrated mixture and by the effect on an alkali metal disulphite, preferably sodium disulphite. A zolmitriptan toluene solvate, characterized by a toluene content of 9 to 14% by weight according to the gas chromatography determination and by a maximum of the corresponding mass loss at temperatures of about 111° C. in the gravimetric analysis record. A zolmitriptan toluene solvate, showing strong Raman bands at the wave numbers of 1443 and 1354 cm?1, characteristic for the crystal lattice of zolmitriptan with built-in toluene, and further marked bands at 1004 and 786 cm?1, characteristic for toluene.

Abstract: A method for the preparation of zolmitriptan or its pharmaceutically acceptable salts, comprising isolation of a crystalline salt of zolmitriptan, its optional re-purification and conversion to the substance of formula (III). Zolmitriptan hydrochloride in the crystalline state.

Abstract: In the preparation of zolmitriptan of formula III the reduction of the diazonium salt to (5)-4-(4-hydrazinobenzyl)-1,3-oxazolidin-2-one of formula IV is performed in a more concentrated mixture and by the effect on an alkali metal disulphite, preferably sodium disulphite. A zolmitriptan toluene solvate, characterized by a toluene content of 9 to 14% by weight according to the gas chromatography determination and by a maximum of the corresponding mass loss at temperatures of about 111° C. in the gravimetric analysis record. A zolmitriptan toluene solvate, showing strong Raman bands at the wave numbers of 1443 and 1354 cm?1, characteristic for the crystal lattice of zolmitriptan with built-in toluene, and further marked bands at 1004 and 786 cm?1, characteristic for toluene.