Abstract
The title compounds, C20H16N2O3S, (I), and C21H18N2O3S, (II), differ by the presence of a methyl group in position 5 on the 1H-indole-2-one ring of compound (II). The two compounds have a structural overlap r.m.s. deviation of 0.48 Å. There is a significant difference in the conformation of the thia-zolidine ring: it has a twisted conformation on the fused N-C bond in (I), but an envelope conformation in compound (II) with the S atom as the flap. The planar pyrrolidine ring of the indole ring system is normal to the mean plane of the five-membered pyrrolidine ring of the pyrrolo-thia-zole unit in both compounds, with dihedral angles of 88.71 (9) and 84.59 (8)°. The pyran rings in both structures have envelope conformations with the methyl-ene C atom adjacent to the C=O group as the flap. In both compounds, there is a short intra-molecular C-H⋯O contact present. In the crystal of (I), mol-ecules are linked by C-H⋯O hydrogen bonds forming chains propagating along the b-axis direction. The chains are linked by N-H⋯π inter-actions, forming layers parallel to (10). In the crystal of (II), mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming inversion dimers which are linked by C-H⋯O hydrogen bonds to form a three-dimensional structure.
Highlights
In view of the importance of such compounds, we report on the synthesis and molecular and crystal structures of the title compounds, 6a,6b,7,11a-tetrahydro-6H,9H-spiro[chromeno[30,40:3,4]pyrrolo [1,2-c]thiazole-11,30-indoline]-20,6-dione (I) and 50-methyl-6a,6b,7,11a-tetrahydro-6H,9H-spiro[chromeno[30,40:3,4]pyrrolo [1,2-c]thiazole-11,30-indoline]-20,6-dione (II)
The molecular structures of both compounds are influenced by a short intramolecular C—HÁ Á ÁO contact (Tables 1 and 2), which forms an S(5) ring motif (Figs. 1 and 2)
There is a significant difference in the conformation of the five-membered thiazolidine ring in the two compounds
Summary
Indole derivatives have been reported to exhibit a large number of biological activities, such as anti-inflammatory (Chen et al, 2017), anti-fungal (Singh et al, 2000), antihepatitis B virus (Chai et al, 2006) and anti-HIV (Sriram et al, 2006; Pandeya et al, 2000). Indole analogues play a significant role in a diverse array of products, such as vitamin supplements, dyes, plastics, flavour enhancers, and in the agricultural and perfumery industries (Barden, 2011). In view of the importance of such compounds, we report on the synthesis and molecular and crystal structures of the title compounds, 6a,6b,7,11a-tetrahydro-6H,9H-spiro[chromeno[30,40:3,4]pyrrolo [1,2-c]thiazole-11,30-indoline]-20,6-dione (I) and 50-methyl-6a,6b,7,11a-tetrahydro-6H,9H-spiro[chromeno[30,40:3,4]pyrrolo [1,2-c]thiazole-11,30-indoline]-20,6-dione (II)
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