Process for the preparation of a tetrazole derivative in two crystalline forms and a new crystalline form of this derivative

摘要

Prepn. of 2-n-butyl-3-((2'-(tetrazol-5-yl)-biphenyl-4-yl)methyl)-1,3-diaza- -spiro(4.4)-non-1-ene-4-one (I) comprises: (a) treating 2-n-butyl-3-((2'-cyanobiphenyl-4-yl)methyl)-1,3-diazaspiro(4.4) non-1-ene-4-one (II) with an alkaline azide and Et3N.HCl in an inert, polar, aprotic solvent and recovering (I) in the form of an alkaline salt in aq. soln; (b) neutralising to pH 4.7-5.3, and (c) crystallising the pptd. prod. (i) in a solvent contg. < 10 vol.% water to obtain (I) in form A (i.e. (IA)) having a specified X-ray diffraction pattern; or (ii) in a solvent miscible with water contg. > 10 vol.% water to isolate (I) in form B (i.e. IB)) which has a different specified X-ray diffraction pattern. Also claimed is the prepn. of (IB) comprising recrystallising (IA) or (I) in a solvent miscible with water contg. ≥ 10% water. (IB) having a specified X-ray diffraction pattern, m.pt. 185-186 degrees C. and IR absorption at 1537,1200 and 745 cm<-1> or obtd. by the above processes is new.