1. Open your EndNote library, and select references you want to export to BibTex format
2. Make sure that BibTeX is an export option:
From Edit – Output Styles -- Open Style Manager...
On the next EndNote Styles screen, scroll down to the BibTeX Export entry and click the checkbox, then close the EndNote Styles window.
From Edit – Output Styles, Make sure that the option BibTeX Export is checked in the Output Styles menu as well
3. Click File—Export. this will open a dialog for saving your file
4. Navigate to the directory where you want to save your BibTex file,
Select Text File (*.txt) from the file type dropdown menu
Save your file as filename.bib
Note: BibTex entries exported from EndNote do not have a BibTex Key. You will need to create a key for each entry.