The recent developments in conventional synthesis of naphthol are summarized, including sulfonation alkali-fusion, via isopropyl naphthalene, hydrolysis, via tetrahydronaphthalene.
That's because, like naphthalene, paradichlorobenzene has a very strong smell and it can interfere with some of the bacteria producing the extra smelly ammonia.
In the early days of urinal cakes, probably around the turn of the 20th century, the little slabs were mostly made of naphthalene, AKA, olden-day moth balls.
Many urinal cakes these days are made of a compound called a molecule that looks a little bit like a throwing star and is often used as a naphthalene replacement in moth balls.