It can take time for Google to recrawl your site and update its index. Are you sure these URLs are returning an appropriate status code?
Make removal permanent
The Remove URLs tool is only a temporary removal. To remove content or a URL from Google search permanently you must take one or more of the following additional actions:
Remove or update the actual content from your site (images, pages, directories) and make sure that your web server returns either a 404 (Not Found) or 410 (Gone) HTTP status code. Non-HTML files (like PDFs) should be completely removed from your server. (Learn more about HTTP status codes)
The fact is: you don’t control the Google index, Google does.
Give it time and the crawlers will only go to a page and get 404 so many times before they drop it form SERPs.
Though I have found that they can remain indexed for some considerable time, with 404s for long gone pages still appearing in Search Console. This suggests that they may remain in the index and crawlers may occasionally look, but the important thing is they are gone from SERPs.
You may want to set up 301 redirects for equivalent pages or 410 headers to say it’s gone in htaccess.
Too late now, but a tip for future projects. If you have a site in development on-line, you may want to use robots.txt or the robots metatag to keep the pages out of indexes during development.
Set up a 301 redirect from the old URL to another relevant page on your site.
Remove it from any XML sitemaps…
Manually remove it from Google’s index (i think others have also mentioned this)
setting the 301’s is important, if any other website still links to your old URL but you haven’t redirected it Google will try to crawl the page still and re-index it… even after you manually remove it.