A 1,6-β-glucan synthetase inhibitor is provided, having potent growth inhibition and having excellent safety.
A compound is provided, capable of expressing in a wide spectral range and specifically or selectively, an antifungal effect based on its functional mechanism of 1,6-β-glucan synthesis inhibition. Also provided is a drug, especially an antifungal that contains the compound, its salt or their hydrate. Concretely, provided are a compound of the following formula (I), its salt or their hydrate, and a drug or antifungal containing, as the active ingredient, the compound, its salt or their hydrate: