The present invention relates to a method for preparing (4R 6S) (E) 6 [2 (2 cyclopropyl) 4 (4 Fluorophenyl)quinoline 3 yl] vinyl 2 2 dimethyl 1 3 dioxane 4 yl]acetic acid ester derivative which is an intermediate of pitavastatin or of the salt thereof into a crystalline solid form. In addition the present invention relates to a novel solvate of the intermediate and to a method for preparing pitavastatin or the salt thereof using the intermediate.
