Unable to sync iPod touch with macbook pro to download new purchases from I-tunes

You are not giving much info to help you:

What exactly happens when you try to sync?

Does iTunes see the iPod?

Was the iPod previous synced to another iTunes library/computer?

Have you successfully synced from this iTunes library/computer before?

If so have you done anything like update iTunes on the computer since it last successfully synced?

Do the songs play in iTunes?

Does any media now sync to the iPod?

Do you have the right boxes checked to sync?

iTunes: Syncing media content to iOS devices and iPod

Try syncing using the manual method

Managing content manually on iPhone, iPad, and iPod