ERROR opening https://cactus.nci.nih.gov/chemical/structure/C%28%3DNNC1%3DNCCN1%29c1c2ccccc2c%28C%3DNNC2%3DNCCN2%29c2ccccc12/file?format=sdf&get3d=True  -- C%28%3DNNC1%3DNCCN1%29c1c2ccccc2c%28C%3DNNC2%3DNCCN2%29c2ccccc12 could not be loaded.