Venkataprasad Jalli

Synthesis of Novel Spiro[indol-2,2′-pyrroles] Using Isocyanide-Based Multicomponent Reaction

Abstract An efficient and facile method for the synthesis of novel spiro[indole-2,2′-pyrroles] from N-methyl-3-isatin imines, t-butyl isocyanide, and dialkyl acetylenedicarboxylate has been achieved by [3 + 2] cyclo addition reaction. All the products were purified by column chromatography as yellow solids and confirmed with 1H NMR, 13C NMR, fast atom bombardment, mass, and infrared. Compound 11 was further confirmed with x-ray analysis. GRAPHICAL ABSTRACT

Crystal structure of ethyl 2-(2-{1-[N-(4-bromo-phen-yl)-2-oxo-2-phenyl-acetamido]-2-tert-butyl-amino-2-oxo-ethyl}-1H-pyrrol-1-yl)acetate.

In the title compound, C28H30BrN3O5, there is an intramolecular N—H⋯O hydrogen bond and an intramolecular C—H⋯O hydrogen bond, both forming S(9) ring motifs. The planes of the 4-bromophenyl ring and the phenyl ring are inclined to that of the pyrrole ring by 48.05 (12) and 77.45 (14)°, respectively, and to one another by 56.25 (12)°. In the crystal, molecules are linked via C—H⋯O hydrogen bonds and C—H⋯π interactions, forming slabs parallel to (10-1).

Crystal structure of benzyl 3-oxo-2-oxa-5-aza-bicyclo-[2.2.1]heptane-5-carboxyl-ate.

The title compound, C13H13NO4 (also known as N-benzyloxycarbonyl-4-hydroxy-l-proline lactone), crystallizes with two molecules in the asymmetric unit. They have slightly different conformations: the fused ring systems almost overlap, but different C—O—C—C torsion angles for the central chains of −155.5 (2) and −178.6 (2)° lead to different twists for the terminal benzene ring. In the crystal, the molecules are linked by C—H⋯O interactions, generating a three-dimensional network. The absolute structure was established based on an unchanging chiral centre in the synthesis.

Crystal structure of 3,4-dimethyl 2-(tert-butyl­amino)-5-[2-oxo-4-(thio­morpholin-4-yl)-2H-chromen-3-yl]furan-3,4-di­carboxyl­ate ethyl acetate hemisolvate

In the title hemisolvate, C25H28N2O7S·0.5C4H8O2, the thiomorpholine ring adopts a chair conformation, with the exocyclic N—C bond in an equatorial orientation. The dihedral angle between the coumarin ring system (r.m.s. deviation = 0.044 Å) and the furan ring is 64.84 (6)°. An intramolecular N—H⋯O hydrogen bond closes an S(6) ring. The ethyl acetate solvent molecule is disordered about a crystallographic inversion centre. In the crystal, the components are linked by C—H⋯O and C—H⋯S hydrogen bonds, generating a three-dimensional network.

Crystal structure of (tert-butyl­carbamo­yl)(4-chloro-2-oxo-2H-chromen-3-yl)methyl acetate

In the title compound, C17H18ClNO5, which was synthesized by reacting 4-chloro-3-formylcoumarin, acetic acid and tert-butyl isocyanide, the acetamido side chain is convoluted with ring-to-side chain C—C—C—C, C—C—C—N and C—C—N—C torsion angles of −123.30 (14), −135.73 (12) and 176.10 (12)°, respectively. In the crystal, N—H⋯O and weak C—H⋯O hydrogen bonds are present, which together with π–π coumarin-ring interactions [ring centroid separations = 3.4582 (8) and 3.6421 (9) Å], give rise to a layered structure lying parallel to (001).

Crystal structure of (1R,4R)-tert-butyl 3-oxo-2-oxa-5-aza-bicyclo-[2.2.2]octane-5-carboxyl-ate.

In the title compound, C11H17NO4, commonly known as N-tert-butoxycarbonyl-5-hydroxy-d-pipecolic acid lactone, the absolute configuration is (1R,4R) due to the enantiomeric purity of the starting material which remains unchanged during the course of the reaction. In the crystal there no intermolecular hydrogen bonds.