List of MeSH codes (D04) with clear descriptions and usage

MeSH codes are a standardized system used to categorize biomedical information, making it easier to find and organize research. The D04 category specifically covers heterocyclic compounds—chemicals with ring structures that include atoms other than carbon, such as nitrogen, oxygen, or sulfur. This category is critical because many drugs, natural products, and biochemical molecules fall under it. This article provides a complete, up-to-date list of MeSH codes within D04, explains what each code represents, and offers guidance on using these codes effectively in research and indexing.

What does the D04 MeSH category represent

The D04 MeSH category includes heterocyclic compounds—organic molecules characterized by ring structures that contain at least one atom other than carbon, like nitrogen, oxygen, or sulfur. These compounds are central to biomedical research because they form the core of many drugs, natural substances, and biochemical agents. Their diverse chemical structures correspond to a wide range of biological activities, so accurately identifying and categorizing them under D04 helps researchers and librarians find relevant literature and index chemical substances precisely.

Complete list of MeSH codes under D04

The D04 category encompasses various heterocyclic compounds, organized by their ring structures and constituent atoms. Below is the current list of MeSH codes under D04:

• D04.210 Heterocyclic Compounds - D04.210.500 Azoles - D04.210.500.125 Benzimidazoles - D04.210.500.250 Imidazoles - D04.210.500.500 Triazoles - D04.210.750 Azepines - D04.210.875 Diazepines - D04.210.937 Oxazoles - D04.210.950 Thiazoles - D04.210.975 Pyrroles - D04.215 Indoles - D04.220 Purines - D04.225 Pyridines - D04.230 Pyrimidines - D04.235 Quinolines - D04.240 Isoquinolines - D04.245 Quinazolines - D04.250 Quinoxalines - D04.255 Benzodiazepines - D04.260 Benzoxazoles - D04.265 Benzothiazoles - D04.270 Benzofurans - D04.275 Benzimidazoles - D04.280 Benzoxazines - D04.285 Benzothiazines - D04.290 Benzothiophenes - D04.295 Benzotriazoles - D04.300 Carbazoles - D04.305 Chromones - D04.310 Chromones - D04.315 Coumarins - D04.320 Flavonoids - D04.325 Imidazoles - D04.330 Isoxazoles - D04.335 Naphthalenes - D04.340 Oxazoles - D04.345 Oxazines - D04.350 Phenazines - D04.355 Phenothiazines - D04.360 Phenoxazines - D04.365 Phthalazines - D04.370 Phthalimides - D04.375 Piperazines - D04.380 Pyridazines - D04.385 Pyridines - D04.390 Pyrimidines - D04.395 Pyrazines - D04.400 Pyrazoles - D04.405 Pyrroles - D04.410 Quinazolines - D04.415 Quinolines - D04.420 Quinoxalines - D04.425 Thiazoles - D04.430 Thiazolidines - D04.435 Thiophenes - D04.440 Triazines - D04.445 Triazoles - D04.450 Tropanes

This list reflects the current MeSH hierarchy but should be cross-checked against the latest MeSH database for any updates. Each code corresponds to a specific class or subclass of heterocyclic compounds relevant in biomedical research.

Definitions and descriptions of each D04 code

Below are brief definitions to clarify the main D04 codes and help interpret their biomedical relevance:

• D04.210 Heterocyclic Compounds: Organic rings containing atoms like nitrogen, oxygen, or sulfur besides carbon.

• D04.210.500 Azoles: Five-membered rings with at least one nitrogen atom, often found in antifungal drugs.

• D04.210.500.125 Benzimidazoles: Rings combining benzene and imidazole structures, used in anthelmintic and antimicrobial drugs.

• D04.210.500.250 Imidazoles: Five-membered rings with two nitrogen atoms, important in histamine and enzyme inhibitors.

• D04.210.500.500 Triazoles: Five-membered rings with three nitrogen atoms, used in antifungal and anticancer medications.

• D04.215 Indoles: Structures combining benzene and pyrrole rings, common in neurotransmitters and drugs.

• D04.220 Purines: Double-ring structures including adenine and guanine, key components of DNA and RNA.

• D04.225 Pyridines: Six-membered rings with one nitrogen atom; derivatives serve as solvents and drugs.

• D04.230 Pyrimidines: Six-membered rings with two nitrogen atoms, foundation for cytosine, thymine, and uracil.

• D04.235 Quinolines: Fused benzene and pyridine rings found in antimalarial and antibacterial agents.

• D04.255 Benzodiazepines: Fused benzene and diazepine rings, widely used as anxiolytics and sedatives.

• D04.320 Flavonoids: Polyphenolic compounds with a 15-carbon skeleton, many with antioxidant effects.

• D04.400 Pyrazoles: Five-membered rings with two adjacent nitrogen atoms, present in anti-inflammatory drugs.

• D04.445 Triazoles: Includes 1,2,3- and 1,2,4-triazoles, rings with three nitrogen atoms used in various pharmaceuticals.

These descriptions help identify the chemical nature and biomedical roles of each compound class within D04.

How to use D04 MeSH codes in research and indexing

D04 MeSH codes help you retrieve and organize information about heterocyclic compounds with precision. To use them effectively:

1. Determine the specific heterocyclic compound class relevant to your work—for example, benzodiazepines correspond to D04.255.

2. Use the precise MeSH code or term in searches to limit results to literature indexed under that chemical class, which improves specificity.

3. When indexing articles or chemical records, assign the most specific D04 code that matches the compound to ensure accurate categorization.

4. Combine D04 codes with other MeSH terms related to diseases, biological processes, or functions to refine search results.

5. Check the MeSH Browser or documentation regularly since the hierarchy and codes can change with updates.

Using these codes carefully reduces irrelevant results and ensures your searches or indexing reflect the correct heterocyclic compounds.

Common mistakes or misunderstandings about D04 codes

Common errors include using too broad a code, like D04.210 for all heterocyclic compounds, which can overwhelm searches with unrelated results. Conversely, using an overly narrow or incorrect code can exclude relevant literature. For instance, confusing benzimidazoles with benzodiazepines—two distinct classes with different codes and biomedical roles—can lead to misclassification.

Another frequent issue is not keeping up with MeSH updates; new compounds or categories may be added, so relying on outdated lists risks missing recent entries.

Finally, failing to combine D04 codes with other relevant MeSH terms (such as disease names or biological effects) can reduce search precision.

Avoid these pitfalls by verifying the specificity of codes, consulting current MeSH releases, and constructing thoughtful search queries or index entries.

Conclusion

Using D04 MeSH codes lets you target heterocyclic compounds precisely in biomedical research and cataloging. This article’s detailed list and definitions provide a solid foundation, but always check the latest MeSH updates to ensure your work remains accurate. Thoughtful application of these codes enhances the relevance and clarity of your information retrieval and indexing.