Crystalline germaazaspirodiones,their preparation and their use in the preparation of germaazaspiranes.

摘要

Novel high purity crystalline forms of dialkylgermaazaspirodiones, their preparation and their use in an improved process for the preparation of high purity dialkylgermaazaspiranes and their acid addition salts are disclosed.

The dialkylgermaazaspirodiones are of the formula:
<Chemistry id="chema01" num="0001"><Image id="ia01" he="27" wi="82" file="IMGA0001.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>wherein R<Sup>1</Sup> and Rare the same or different alkyl groups of 1 to about 4 carbon atoms and R<Sup>3</Sup> and R are the same or different alkyl groups of 1 to about 4 carbon atoms.

A process of purifying a dialkylgermazaaspirodione of the formula given above comprises crystallizing said dione in the presence or absence of a solvent and separating the resulting crystals from the mother liquor.

A process of preparing a dialkylgermaazaspirane comprises purifying a dialkylgermaazaspirodione of the formula given above by crystallization and reducing the purified dione. A salt may be prepared from the reduced dione by adding an acid thereto.