Might be this guy?
Demetrius Ypsilanti, sometimes spelled Ypsilantis, (1793 - January 3, 1832), second son of Prince Constantine, distinguished himself as a Russian officer in the campaign of 1814, and in the spring of 1821 went to the Morea, where the war of Greek independence had just broken out. He was one of the most conspicuous of the Phanariot leaders during the earlier stages of the revolt, though he was much hampered by the local chiefs and by the civilian element headed by Mavrocordato. In January 1822 he was elected president of the legislative assembly; but the ill-success of his campaign in central Greece, and his failure to obtain a commanding position in the national convention of Astros, led to his retirement early in 1823. In 1828 he was appointed by Capo d'Istria commander of the troops in East Hellas. He succeeded, on the 25th of September 1829, in forcing the Turkish commander Aslan Bey to sign a capitulation at the Pass of Petra, which ended the active operations of the war. He died at Vienna on the 3rd of January 1832.
He was brother of Alexander Ypsilantis.
The city of Ypsilanti, Michigan in the United States of America is named after him.
Nice find
