Error while using Java Pattern compile with regex

Question

I am trying to come up with correct regex for the below usecase:

prefix.string1.anyNumber.string2.anyNumber.string3

example 1: prefix.abcd.22.pqr.55.xyz

example 2: prefix.abcd.22.xyz

example 3: prefix.pqr.55.xyz

Need to generate a regex that I can use to generate Pattern in java.

I tried the below:

String regex = "prefix\.abcd\.\d\.pqr\.\d\.xyz|prefix\.abcd\.\d\.xyz|prefix\.pqr\.\d\.xyz"
Pattern p = Pattern.compile(regex);

It does not work. I have not used patterns much before. Trying to figure out what I am missing here. Appreciate any help. Thank you.