Ethyl 2-[N-(tert-butyloxycarbonyl)-L-alanylamino]-4-methyl-1,3-thiazole-5-carboxylate reveals a trans orientation of the preceding amide N-H with respect to the thiazole-ring sulfur

The title molecule, C15H23N3O5S, was prepared as a synthetic precursor to 4 -methylthiazole-based DNA minor groove binders which would bear chiral amin o acids in the sequence. The crystallographic evidence presented herein sho ws that the aromatic amide NH group preceding the thiazole ring points away from the direction of sulfur. The molecule is biplanar, with the dihedral angle between the N-terminus peptide moiety and the thiazole-containing pla ne being 49.7 (5)degrees, with a bend at the C alpha carbon.