Is it obligatory for someone who bought a plot of land with his own money and registered it in his name and the names of two of his brothers with the intention of shared dwelling to give them a share of its sale price later, with their consent to the sale?

What you did is a gift (hiba), and if its conditions were met—namely, that the donor was qualified to dispose [of the property] and the donee took full possession of it—then the donor has no right to revoke it, for the Messenger of Allah, peace and blessings be upon him, said: "The one who revokes his gift is like a dog that returns to its vomit."

So, if you left the land to your two brothers, they have taken ownership of it, and you cannot revoke [the gift]. If they agree to sell it, there is no harm, and the price will be divided among you according to your shares.

However, if they did not take possession of the land and you remained in control of it, you can revoke [the gift], for Ibn Abi Zayd al-Maliki said: "A gift, a charity (sadaqah), or an endowment (habs) is not complete except by possession." It has been reported that Abu Bakr gifted something to Aisha, but when she did not take possession of it, he considered it a part of the inheritance.

It is better not to revoke a gift absolutely. If they agree to sell the land, there is no harm in that.