(20R,25S)-2-Methylene-19,26-Dinor-1alpha,25-Dihydroxyvitamin D3 in Crystalline Form

A method of purifying (20R,25S)-2-methylene-19,26-dinor, 1α,25-dihydroxyvitamin D3, 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 D3 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 D3 crystals;
• and
• (d) separating the (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D3 crystals from the solvent.

A method of purifying (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D3, 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 D3 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 D3 crystals;
• and
• (d) recovering the (20R,25S)-2-methylene-19,26-dinor-1α,25-dihydroxyvitamin D3 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.