Crystallization of the drug propranolol with dicarboxylic acids yielded molecular salts with oxalic and fumaric acids in molar ratios of 1 : 1 and 2 : 1, with maleic acid in a molar ratio of 1 : 1.

The title compounds consist of a bornane skeleton with attached acetamide, C₁₂H₂₁NO (±)-(1) {systematic name: (±)-N-[(1RS,2RS,4RS)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl]acetamide}, and chloroacetamide, C₁₂H₂₀ClNO (±)-(2) {systematic name: (±)-2-chloro-N-[(1RS,2RS,4RS)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl]acetamide}, functionalities to the 2-exo-position. The crystal structure of the first monoclinic polymorph of (±)-(1) has been reported previously [Unget al.(2014).Monatsh. Chem.145, 983–992]. Compound (±)-(1) crystallizes in the space groupP2₁/nwith two independent molecules in the asymmetric unit, in contrast to the above-mentioned polymorph which crystallized in the space groupC2/cwith one molecule in the asymmetric unit. In the title compounds, the bicyclic bornane moieties have normal geometries. In the crystals of both compounds, molecules are linked by N—H...O hydrogen bonds, reinforced by C—H...O contacts, formingtrans-amide chains propagating along thea-axis direction. In the case of compound (±)-(1), neighbouring chains are linked by further C—H...O contacts, forming double-chain ribbons along [100].

C₁₆H₁₇NO₃, orthorhombic, P2₁2₁2₁ (no. 19), a = 7.9882 (2) Å, b = 11.4053 (3) Å, c = 16.2381 (5) Å, V = 1479.42 (7) ų, Z = 4, R _gt (F) = 0.0480, wR _ref (F ² ) = 0.0991, T = 173 K.

The title compound, C₂₃H₂₅N₃O₄, {systematic name: 1-benzyl-4-[(3aR,5R,6R,6aR)-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl]-1H-1,2,3-triazole}, consists of a substituted 2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole. The furanose ring adopts an envelope conformation close toC₃-exo, where the C atom substituted by the benzyloxy group is the flap. The fused dioxolane ring also adopts an envelope conformation, with the methylene C atom as the flap. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming zigzag chains along [010].

The title compound, C₂₁H₂₉NO₇(1) [systematic name: benzyl ({(3aR,5S,6R,6aR)-5-[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-6-yl}methyl)carbamate], consists of a substituted 2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxolane skeleton. The furanose ring adopts an envelope conformation close toC₃-exo, where the C atom substituted by the benzyl carbamate group is the flap. The fused dioxolane ring also adopts an envelope conformation, as does the terminal dioxolane ring, with in each case an O atom as the flap. In the crystal, molecules are linked by N—H...O and C–H...O hydrogen bonds, forming chains propagating along theb-axis direction.

The title compound, C₁₃H₂₁NO₇{systematic name: (3aR,5S,6R,6aR)-5-[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-6-(nitromethyl)tetrahydrofuro[2,3-d][1,3]dioxole}, consists of a substituted 2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxolane skeleton. The furanose ringAadopts a^oT₄conformation. The fused dioxolane ringBand the substituent dioxolane ringCalso have twisted conformations. There are no strong hydrogen bonds in the crystal structure: only weak C—H...O contacts are present, which link the molecules to form a three-dimensional structure.