INDEX recrystallization

The tartrate salt is recrystallized by dissolving in hot methanol, filtering, adding hot ethanol to the filtrate and cooling. The product is collected and air-dried. MP 148°-150°C. A second crop is obtained from the filtrate for a total yield of 59%. The tartrate is then metathe-sized with pamoic acid (Merck Index 6867) to give pyrantel pamoate as the product. 

Fig. 4a. Resolution of racemic (67) by column chromatography on microcrystalline cellulose triacetate (column B) and by recrystallization 35) C = crystals M = mother liquor the index following C or M gives the number of recrystallizations the fraction has undergone. The value of [ot] ° is given, followed by the quantity obtained...

Jackson and McDonald13 analyzed samples of inulin from various sources. They obtained a uniform product by recrystallization from water, irrespective of the source. Since they determined total solids by refractive index and density measurements on the hydrolyzed inulin, they were not concerned with its crystalline form nor with its moisture content. 

For powder photographs, the use of the charts described on p. 143 and in Appendix 3 will show whether the substance is cubic, tetragonal, or hexagonal if it is not, the numerical methods of indexing the patterns of crystals of low symmetry may be tried or, if it is. possible to pick out single crystals, or if the specimen can be recrystallized to give suitable crystals, the unit cell dimensions may be determined by the methods described earlier. A search may then be made in the tables of Donnay and Nowacki (1954), in which, for each crystal system, the species are arranged in order of the axial ratios. 

The double melting point has been observed in only one 5 of the previous studies. The initial melting point varies with the state of subdivision and is not a reliable index of purity. Several recrystallizations did not change the melting behavior or the remelt temperature. The checkers did not observe the double melting point with the product initially obtained, but did so with material recrystallized once. 

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