In the title compound, C(11)H(8)O(3)S(2), the dihedral angle between the mean planes of the two thio-phene rings is 65.10 (10)°. Intra-molecular C-H⋯O inter-actions form S(6) and S(7) ring motifs. In the crystal, chains along the a axis are formed by C-H⋯O inter-actions. Adjacent chains are connected into a three-dimensional network by C-H⋯O and O-H⋯O inter-actions.

In the title compound, C(14)H(10)N(2)O, the dihedral angle between the imidazo[1,2-a]pyridine and phenyl rings is 28.61 (4)° The mol-ecules are connected into broad chains parallel to the a axis by weak C-H⋯O and C-H⋯N hydrogen bonds. The linking of the ribbons is provided by π-π stacking inter-actions between neighbouring pyridine rings, with a centroid-centroid distance of 3.7187 (7) Å.

The quinoline fused-ring system of the title compound, C(11)H(8)ClNO, is planar (r.m.s. deviation = 0.005 Å); the formyl group is slightly bent out of the plane [C-C-C-O1 torsion angles = 8.8 (7) and -172.8 (4)°].

All the non-H atoms of the title compound, C(12)H(10)ClNO, lie on a crystallographic mirror plane orientated perpendicular to the crystallographic b axis.

The quinoline fused-ring system of the title compound, C(11)H(8)ClNO(2), is planar (r.m.s. deviation = 0.0095 Å); the formyl group is slightly bent out of this plane [C-C-C-O torsion angles = -2.4 (3) and 175.9 (2)°].

The quinoline fused-ring system of the title compound, C(11)H(8)ClNO, is planar (r.m.s. deviation = 0.007 Å); the formyl group is bent slightly out of the plane [C-C-C-O torsion angles = -9.6 (5) and 170.4 (3)°].

In the title compound, C(11)H(8)ClNO(2), the quinoline fused-ring system is almost planar (r.m.s. deviation = 0.020 Å). The formyl group is slightly bent out of the quinoline plane [deviation of the O atom = 0.371 (2) Å].

The quinolinyl fused-ring of the title compound, C(11)H(8)ClNO, is almost planar (r.m.s. deviation = 0.013 Å); the formyl group is slightly bent out of the plane of the fused ring system [C-C-C-O torsion angle = 13.5 (4)°].

A new alkaloid, 2-(furan-2-yl)-6-(2S,3S,4-trihydroxybutyl)pyrazine (1), along with 12 known compounds, 2-(furan-2-yl)-5-(2S,3S,4-trihydroxybutyl)pyrazine (2), (S)-4-isobutyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (3), (S)-4-isopropyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (4), (4S)-4-(2-methylbutyl)-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-...