SAN FRANCISCO — Paul Vapnek, considered a dean of legal ethics in California and a longtime intellectual property lawyer, died in his sleep on Saturday. He was 86.

“Paul liked the law. He enjoyed the challenges that our field presented him. He enjoyed the interchange and the dialogue. And that was infectious. He got the rest of us to enjoy it as well,” said Mark Tuft, a partner at Cooper, White & Cooper who co-authored the Rutter Group’s California Practice Guide on Professional Responsibility with Vapnek.