Computer-Assisted Design of Organic Synthesis

Much commercial work on organic synthesis relies heavily on computer-aided-design. This teaching package demonstrates in a clear and concise manner how such CAD works by allowing the construction of synthetic routes from a target molecule. Its purpose is to teach how computers may be used to design organic syntheses and it is loosely based on the much more sophisticated LHASA programme, available on larger computers. However, its advantage over LHASA is that it makes parts of the design process "visible" to students. Enough practical chemistry hints are given in the accompanying manual for the work done on the system to be put in context of practical organic lab sessions. The software is written in BASIC and runs on the BBC Model B or Master series. The package consists of three programmes. The first is a general purpose drawing programme which allows the operator to input to the computer the structure to be synthesised. No special training is needed, and the structure is displayed in the standard format familiar to chemists.
An important aspect is the ability to look at the connection tables, central to the storage of structural information by the computer, a point which helps students to understand the nature of these tables. When the drawing has been completed, the second programme is loaded. This is termed the "perception phase". The structure is examined for synthetically important features (functional groups, rings) and a list of perceived groups is displayed. In excess of 40 functional groups can be separately recognised, and moderately complex ring systems. The final programme is the important "synthesis phase". The perceived functional groups invoke certain retrosynthetic 'transformations'; the target molecule is disconnected and both target and sub-target are displayed, along with minimal information about the reaction required to convert sub-target into target. When no more reactions are found, the programme finishes by displaying the synthesis tree. Enough practical examples with comprehensive instructions are given in the accompanying manual for the work done on the system to be put in context of practical organic lab sessions.
Instructions for producing hard copy are also included, using a demonstration file already stored on the disk.