Are there any additional clauses in the contract that can prohibit any conversions?
Don't think so.
Perhaps read it yourself. The plan is to settle part in cash and part in shares (for a decent price).
I don't think he wants to ruin his reputation. Piss off Solomon forever. And alienate himself from the rest of the shareholder base. Etc. I think he understands there is only one way to make this work. In fact, if he converts for 1.50, we could see a rally. Maybe.