Convert PDF to CDX

Understanding PDF and CDX file formats

PDF (Portable Document Format) is a widely used file format developed by Adobe for presenting documents, including text and images, independent of software, hardware, or operating systems. CDX is a file format used by ChemDraw, a popular chemical structure drawing application. CDX files store chemical structure diagrams and related data, making them essential in chemistry and pharmaceutical industries.

Why convert PDF to CDX?

Converting a PDF containing chemical structures to a CDX file allows you to edit and manipulate the chemical diagrams in ChemDraw. This is particularly useful for researchers and chemists who need to extract and modify chemical information from published documents or scanned articles.

How to convert PDF to CDX

Direct conversion from PDF to CDX is not straightforward because PDF files are not inherently chemical-aware. However, you can use a combination of tools to achieve this:

1. Extract chemical structures from PDF: Use ChemScanner (a ChemDraw plugin) or OSRA (Optical Structure Recognition Application) to recognize and extract chemical structures from PDF files. OSRA can convert images of chemical structures into machine-readable formats.
2. Convert extracted structures to CDX: Once the chemical structure is recognized, save or export it as a CDX file using ChemDraw.

Step-by-step conversion process

1. Open your PDF file and identify the chemical structure you want to convert.
2. Use OSRA to process the PDF or image and generate a structure file (such as MOL or SDF).
3. Open the generated file in ChemDraw by selecting File → Open.
4. Once the structure appears in ChemDraw, save it as a CDX file by choosing File → Save As and selecting the CDX format.

Recommended software for PDF to CDX conversion

• ChemDraw: The industry standard for chemical structure editing and CDX file creation.
• OSRA: Free, open-source tool for optical recognition of chemical structures from images and PDFs.
• ChemScanner: A ChemDraw plugin that can extract chemical structures from PDF documents.

Tips for successful conversion

• Ensure the chemical structures in the PDF are clear and high-resolution for better recognition accuracy.
• Manually verify and edit the extracted structures in ChemDraw to correct any recognition errors.
• Always save your work in the native CDX format for full compatibility with ChemDraw features.