Crystal and Molecular Structure of 3-(Adenin-9-yl)propiontryptamide

The crystal structure of 3-(adenin-9-yl)propiontryptamide (3-(adenin-9-yl)-N-[2-(3-indolyl)ethyl]propionamide) has been investigated as a model for adenine-tryptophan interaction. The space group of the crystal is P21/c, with dimensions a=8.512(2), b=16.884(3), c=12.405(3) Å, β=105.54(2)°, and Z=4. The structure was solved by the direct method and refined by a block-diagonal least-squares method. A slight overlapping between adenine and indole moieties is found, but it may not be sufficient to produce a strong π-π interaction. The adenine base is paired with that related by the centre of symmetry through two N(6)H···N(1) hydrogen bonds, and also with the other centrosymmetrically related adenine base through two N(6)H···N(7) hydrogen bonds. Adenine and indole are bound through a hydrogen bond between N(7) of adenine and imino nitrogen of indole.