Structure and taste of 3,6:3′,6′-dianhydro-α,α-trehalose monohydrate

The X-ray diffraction structure of 3,6: 3′,6′-dianhydro-α,α-trehalose (3,6-anhydro-α-d-glucopyranosyl 3,6-anhydro-α-d-glucopyranoside) monohydrate is described. The molecule has exact two-fold symmetry through the anomeric oxygen atom. The pyranosyl ring has a slightly distorted 1C4 chair conformation and the cis-fused five-membered anhydro ring has a near perfect 4E envelope conformation. X-ray crystal data show an absence of a sweet AH,B glucophore, which would explain the absence of sweetness. Evidence indicating the importance of hydrophobic character to bitterness is presented.