Q: how i sincronize my itunes on my mac from my ipod touch?

By design, iTunes syncing typically works in one direction only, from the computer to the device, not from device to computer.  iTunes can transfer songs purchased from the iTunes Store, because iTunes can verify ownership of those songs.  There are third-party utilities that can transfer from device to computer.

It is best to transfer your complete iTunes library from your old computer to the new Mac.  That way, you can also keep your playlists and other supporting data, such as song ratings and play count.  If you are able to do it that way, please post back.  Or refer to this Apple support document

How to move your iTunes library to a new computer - Apple Support

Songs purchased from the iTunes Store can also be downloaded again, to the new Mac, at no additional cost.  In iTunes, sign in using the Apple ID used to make the purchases.  On the iTunes Store home screen, find and click Purchases (along right side of window).  On the Purchases screen, you can download previous purchases.

Your i-device was not designed for unique storage of your media. It is not a backup device and media transfer was planned with you maintaining a master copy of your media on a computer which is itself independently backed up against loss.  To use a device with a different setup you transfer the old library from a computer or a backup directly to the new setup, not the device to the library. Media syncing is one way, computer to device, updating the device content to the content on the computer, not updating or restoring content on a computer. The exception is iTunes Store purchases which can be transferred to a computer.

Redownload or transfer your iTunes Store purchases from an iPhone, iPad or iPod to a computer - https://support.apple.com/en-us/HT201267 - "This feature works only for content bought from the iTunes Store." As of OS9 no longer does apps which now must be re-downloaded directly from the Store.