PubChem raw data is hosted on the NCBI servers which provide convenient access using rsync.
Download PubChem data using a rsync command like
rsync -Pav ftp.ncbi.nlm.nih.gov::pubchem/Compound/CURRENT-Full/SDF/\*.gz pubchem/
This example command will download all current compounds in SDF format.
You can explore the PubChem directory structure by accessing the NCBI FTP server using your browser.