"purported to" is a valid idiom in written English.
It indicates that something is said or believed to be true, but not necessarily confirmed. For example: "Many people have purported to have seen Bigfoot."
A company purported to exemplify a successful straddling strategy?
It purported to show favorable results from numerous comparison tests.
A second video purported to show a thunderous blast.
Video posted online purported to show the attacks.
I was not very good at that job and I had never purported to be.
– something that at least purported to be unspeakably ancient, predating human history by millennia.
"It is difficult to understand the ecological damage that this is purported to cause.
A clip from activists purported to have been filmed from inside the compound.
He is purported to have said that the Beetle was "too ugly and too noisy".
We believed that a statement, a confession, an incident, was seldom what it purported to be".
The other day we came across a graph that purported to describe the economic future.
