I believe Syria would like a peace agreement, but it is very difficult for any Arab country to abandoned the Palestinians. They are seen as the victims, and Israel is seen as the "Occupier". Normally, I don't believe in linkage, but it would be helpful if peace with the Palesinians was linked to peace with Syria. With Syria and the PA on one side, some compromise might become possible with Hamas, because it would be in Syria's interest to have a peace agreement. If you are serious about a peace treaty drop pre-conditions to negotiations. Only an idiot would surrender before a peace agreement.
U.S. says working on initiative to de-escalate Syria fighting, with focus on Aleppo (Reuters)
from the article: Some serious thoughts on Syria