Green synthesis of coumarin derivatives using Brønsted acidic pyridinium based ionic liquid [MBSPy][HSO4] to control an opportunistic human and a devastating plant pathogenic fungus Macrophomina phaseolina.

An eco-friendly simple protocol has been devised for the preparation of coumarin derivatives using doubly Brønsted acidic task specific ionic liquid (TSIL) as a catalyst. Solvent-free conditions were employed for the reaction of different substituted phenols with ß-ketoester in TSIL to produce corresponding substituted coumarin derivatives in good to excellent yields at ambient conditions; at room temperature and with reduced reaction times. The ionic liquid catalyst can be recycled and reused up to five times. All the synthesized coumarins were evaluated for their antifungal activities against Macrophomina phaseolina, a plant as well as an opportunistic human pathogenic fungus affecting more than 500 plant species worldwide and with no registered commercial fungicide available against it, to date. Amongst all the coumarins tested, compounds 3f and 3i showed excellent antifungal activity comparable to reference fungicide mancozeb. The current methodology provides an easy and expedient way to access the coumarin core in search of potential fungicides for sustainable agriculture.

Crystal structure of N,N'-(1,2-phenyl-ene)bis-(2-chloro-acetamide).

In the title compound, C10H10Cl2N2O2, the secondary amide groups are differently twisted relative to the benzene ring, with dihedral angles between the respective planes of 21.03 (2) and 81.22 (2)°. In the crystal, the mol-ecules are connected by N-H⋯O and C-H⋯O hydrogen bonds, forming a two-dimensional polymeric network parallel to (001). One of the amide carbonyl O atoms accepts two H atoms in N-H⋯O and C-H⋯O inter-actions, forming an R 2 (2)(6) ring motif.

5-Methyl-1-[(4-methyl-phen-yl)sulfon-yl]-1H-pyrazol-3-yl 4-methyl-benzene-sulfonate.

In the title compound, C(18)H(18)N(2)O(5)S(2), the tolyl rings are oriented at a dihedral angle of 16.15 (11)° with respect to one another. The 5-methyl-1H-pyrazol-3-ol ring is roughly planar (r.m.s. deviation = 0.0231 Å) and subtends angles of 73.82 (8) and 89.85 (8)° with the tolyl rings. In the crystal, very weak π-π inter-actions between tolyl groups, with centroid-centroid distances of 4.1364 (19) and 4.0630 (16) Å, together with a C-H⋯π contact generate a three-dimensional network.

2-[(2-Amino-phen-yl)sulfan-yl]-N-(4-meth-oxy-phen-yl)acetamide.

In the title compound, C(15)H(16)N(2)O(2)S, the dihedral angle between the 4-meth-oxy-aniline and 2-amino-benzene-thiole fragments is 35.60 (9)°. A short intra-molecular N-H⋯S contact leads to an S(5) ring. In the crystal, mol-ecules are consolidated in the form of polymeric chains along [010] as a result of N-H⋯O hydrogen bonds, which generate R(3) (2)(18) and R(4) (3)(22) loops. The polymeric chains are interlinked through C-H⋯O inter-action and complete R(2) (2)(8) ring motifs.