The most common and most likely answer to this crossword clue is the 12 letter word PROSPECTUSES
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result PROSPECTUSES
Buddy explains!

The straight part
We know that "brochures" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case brochures = prospectuses.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PROSPECTUSES mean?
PROSPECTUSES noun- A document, distributed to prospective members, investors, buyers or participants, which describes an institution (such as a university), a publication or a business and what it has to offer.
- A document which describes a proposed endeavor (venture, undertaking), such as a literary work (which one proposes to write).
- A booklet or other document giving details of a share offer for the benefit of investors.