Crystalline form of free base of imidazo isoindole derivative and preparation method therefor

The present invention relates to a crystalline form of a free base of an imidazo isoindole derivative and a preparation method therefor. Specifically, the present invention relates to the A, B, C, D,E, and F crystal forms of the compound represented by formula (I), the chemical name being (S)-2-(4-(4-(4-(6-fluoro-5H-imidazo[5,1-a]isoindol-5-yl)piperidine-1-yl)phenyl)-1H-pyrazol-1-yl)ethanol. Thepresent invention also relates to a preparation method for the A, B, C, D, E, and F crystal forms, the use thereof in a pharmaceutical composition, and the uses of the A, B, C, D, E, and F crystal forms and the pharmaceutical composition in the treatment of diseases having an IDO-mediated tryptophan metabolic pathway pathological feature. The A, B, C, D, E, and F crystal forms of formula (I) obtained in the present invention have good stability, and the crystallisation solvent used has low toxicity and low residue, and the crystal forms can be better used for clinical treatment. 本发明涉及种咪唑并异吲哚类衍生物的游离碱的结晶形式及其制备方法。具体而言，本发明