Ronny,
As I kept thinking about our efforts to find Rewoquat W3690 I recalled more detail of the search that might be important to your efforts. We had a local distributor here in Cincinnati for this material. The UC grad students tried to obtain it through them but were told they would only sell to industrial customers – not universities!!! We asked our local Dry Dredgers member who owns a prep lab here if he could try. They would sell to him but only in drum quantities. This may not be of any help to you but I thought you should know the whole story.
Jack