import re
text = r'"prop1": "val1","prop2": "va\" l2" "abcdefg": "h ij kl mn""1234": "5678"'
rx = r'"[^"\\]*(?:\\.[^"\\]*)*"\s*:\s*"[^"\\]*(?:\\.[^"\\]*)*"'
print( ', '.join(re.findall(rx, text, re.S)) )
# => "prop1": "val1", "prop2": "va\" l2", "abcdefg": "h ij kl mn", "1234": "5678"
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