(20R,25S)-2-Methylene-19,26-Dinor-1α,25-Dihydroxyvitamin D

1. (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 in crystalline form.

2. The crystalline form of (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 having molecular packing arrangement defined by space group P1 and unit cell dimensions a=6.4 Å, b=12.6 Å, c=16.0 Å, α=110.9°, β=95.3° and γ=90.6°.

3. A three dimensional structure for (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 as defined by the molecular packing arrangement set forth in claim 2 .

4. A method of purifying (20R,25S)-2-methylene-19,26-dinor, 1α,25-dihydroxyvitamin D 3 , comprising the steps of:

(a) preparing a solvent comprising water and methanol;

(b) dissolving a product containing (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 to be purified in said solvent;

(c) cooling said solvent and dissolved product below ambient temperature for a sufficient amount of time to form a precipitate of (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 crystals; and

(d) separating the (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 crystals from the solvent.

5. The method of claim 4 including the further step of maintaining said solvent and dissolved product at ambient temperature for a period of time prior to cooling below ambient temperature.

6. The method of claim 4 wherein said solvent comprises 20% water and 80% methanol, by volume.

7. The method of claim 4 wherein said solvent and dissolved product are cooled to about −20° C.

8. The method of claim 4 wherein the step of separating comprises filtering the solvent and precipitate to obtain the crystals.

9. The method of claim 4 including a further step (e) comprising repeating steps (a) through (d) using the recovered crystals from step (d) as the product of step (b).

10. The method of claim 7 wherein said solvent and dissolved product are maintained at −20° C. for up to 7 weeks.

11. A method of purifying (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 , comprising the steps of

(a) preparing a solvent comprising 80% methanol and 20% water, by volume;

(b) dissolving a product containing (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 to be purified in said solvent;

(c) cooling said solvent and dissolved product below ambient temperature for a sufficient amount of time to form a precipitate of (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 crystals; and

(d) recovering the (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D 3 crystals having a molecular packing arrangement defined by space group P1 and unit cell dimensions a=6.4 Å, b=12.6 Å c=16.0 Å, α=110.9°, β=95.3° and γ=90.6°, or any other space group that yields substantially the same crystalline packing arrangement.

12. The method of claim 11 wherein said solvent and dissolved product is maintained at ambient temperature for a period of time prior to cooling below ambient temperature.

13. The method of claim 11 wherein said solvent and dissolved product are cooled to about −20° C.

14. The method of claim 13 wherein said solvent and dissolved product are maintained at about −20° C. for up to 7 weeks.

15. The method of claim 11 wherein the step of recovering comprises filtering.

16. The method of claim 11 further including the step of (e) repeating steps (a) through (d) using the recovered crystals from step (d) as the product of step (b).