MCDL format (mcdl)# Modular Chemical Descriptor Language As described in [gb2001]. [gb2001] A.A. Gakh and M.N. Burnett. Modular Chemical Descriptor Language (MCDL): Composition, Connectivity and Supplementary Modules. J. Chem. Inf. Comput. Sci., 2004, 41, 1491-1499. [Link] Here’s an example conversion from SMILES to MCDL: obabel -:"CC(=O)Cl" -omcdl CHHH;COCl[2]