Can I travel to the Netherlands for tourism with a business visa?

You have explained in comments to Tor-Einar's answer that the visit that you described in your application but won't be going on anyway is a

cultural, leisure and educational tour[] to the Netherlands for Iranian scholars and experts who wish to attend in our leisure/cultural tour that is scheduled for May 31st - June 5th, 2018 and will include several visits of cultural points in the Netherlands

That sounds like fancy language for a special-interest tourist visit. The fact that the tour organizer chose to send you something they phrased as an "invitation letter" rather than a plain booking confirmation does not make your planned tourist visit into a business visit.

Your application accurately described something that is a short tourist visit (no matter what your supporting documents called themselves), and you were granted a long multiple-entry visa to go on that visit.

The general rule is that you're allowed to make minor changes of plan, as long as the visit you actually make is still broadly the same as the one you applied for. In your case there are differences that are arguably not quite minor -- most importantly it doesn't sound like your new plans are a package tour -- but it doesn't sound to me like those differences are so large that you can reasonably be suspected of any deceptive intent by having plans for a package tour when you applied and later go on a different tourist trip to the same Schengen country. In particular, you can't be suspected of "consulate shopping", because even if you applied for the later visit you would have done so at the Dutch consulate.

The fact that you were given a multiple-entry visa indicates that you're trusted to arrange new visits with new premises by yourself without having them pre-vetted by a consulate. This ought to mean that you're also free to make changes of the kind you describe here.

What I would do: Go on your now-planned trip. When you're asked your purpose at the border, say something like

I got this visa for a package tour in the beginning of June, but I was prevented from going due to [insert five words about why]. Now I'm going to take a look around on my own instead. I'll be here until next Thursday (or whatever).

Be sure to have concrete plans about your actual visit ready to show at this point, as arriving third-country nationals should always have -- but it's probably not very likely that you will be asked for them.

It will be a hit or miss.

In general, you are allowed to use a multiple entry visa for later trips, which were not planned or anticipated when you initially applied for the visa. As long as you still fulfill all entry critera, you are free to use your visa to enter the Schengen area later for other purposes than the plans you initially provided when applying for the visa.

You are however, still in general, not allowed to provide one story when applying for the visa and later use the visa only for a completely different purpose. If you applied for a visa to do some business in the Netherlands and the first thing you do is to try to use the visa for tourism, perhaps not even in the Netherlands, it can easily be interpreted by the immigration officer that you obtained the visa under false pretence or by deception. He will rightfully refuse entry and may revoke your visa. This will in reality have negative impact on the assessment of any future Schengen visa application you may lodge.

In the end, it will all depend on the amount of scrutiny exercised by the immigration officer. You may have luck and be 'stamped in' without any questions at all, or the immigration officer may start asking questions, in which case your story will soon fall apart and not work.