Sync Notes from Mac and iOS devices without iCloud

NOTE: i assume in my answer that you just don't want the Apple iCloud servers

you need an other email account to do this

• you add one more email account (any but not iCloud)
• and then you activate at this email account the section NOTES
• the notes are created in an imap folder named notes
• do it on both: iPhone and Mac
• then you move all notes on Mac to the other account
• then you can switch off the NOTES with the iCloud account

iPhone (iOS10):

Settings -> Notes -> Accounts -> (some account) -> notes -> switch: on/off

OSX 10.11.6

Settings -> Internet Accounts -> (some account) -> notes -> checkbox: on/off