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Introduction to CH-NMR-NP system

The ¹³C/¹H-NMR database for natural products [CH-NMR-NP] is mainly composed of natural products that were published in major journals in the years between 2000 and the spring of 2014. For a natural product to be included in the database, complete ¹³C-NMR data was a strict precondition. No such precondition was set for ¹H and as a result some compounds show incomplete ¹H-NMR data. As it concerns a database, CH-NMR-NP lacks completeness.
The number of the compounds in natural products compiled from the published papers is about 29,500. Additionally, about 6,000 organic compounds with ¹H/¹³C spectral patterns were compiled from SDBS-NMR, and the total number of the compounds is approximately 35,500.
©Kikuko Hayamizu

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Welcome to CH-NMR-NP

Introduction

CH-NMR-NP is a ¹³C and ¹H NMR database of organic natural products compiled from published papers. The building began in May, 2002 and completed in 2014 summer to check the data. The data are mainly compiled from papers in the following research journals issued mainly from 2000 to spring in 2014. With addition of about 6,000 compoundst from SDBS-NMR, which include ¹H and ¹³C spectral patterns observed. The total number of the data included in CH-NMR-NP is 35,500.

Journals from which data were compiled

• Chem. Pharm. Bull. 2000-2013
• J. Antibiotics 2000-2013
• Tetrahedron + Tetrahedron Letters 2000-2014 spring
• J. Natural Products 2000-2014 spring
• Phytochemistry + Phytochem. Lett. 2000-2013
• J. Org. Chem. + Eur. J. Org. Chem. 2000-2013
• Magn. Reson. Chem. 1996-2013
• Organic Letters 1999-2014 spring
• Other Journals

The principles of data inclusion

1. The chemical shift tables of ¹H and ¹³C data were described.
2. The chemical structure was clearly drawn.
3. The name and molecular formula (consistent with the chemical structure) were given.
4. No obvious errors were found in the original literature source.
5. The compounds were judiciously selected so as not to overlap similar compounds with similar NMR spectra.

As the results, the database does not include every compound that appeared in the above journals.

Chemical Structure with Assignment

• Chemical structure was drawn by using an ISIS_Draw.
• The numbering at the carbon positions corresponds to the ¹H and ¹³C chemical shifts.
• To obtain 1:1 correspondence between the carbon position and the chemical shift, the different numbers are given for each carbon except for equivalent carbons.
• When the carbons in a long alkyl chain give the same chemical shifts, the same number may be given.
• For numbering the carbons, alphabets, Greek characters, or symbols like 1' and 1'' are all converted to figures. The order of the numbering is followed to the authors.

NMR Spectral Data

For each carbon in the chemical structure, following data are given.

1. ¹³C Chemical shift.
2. Number of hydrogen atoms attached ( C, CH, CH₂ and CH₃ )
3. ¹H Chemical shift.
4. ¹H Splitting information and additionaly proton types such as OH, NH, NH₂ and so on.
5. ¹³C Assignment exchangeable, if any.
6. Number of equivalent carbons.

Compound Information

• "Name" is the compound name given by the authors in the literature.
• "Molecular Formula" is molecular formula derived from the chemical structure of ISIS/Base.
• "Molecular Weight" is the molecular formula calculated from the chemical structure by ISIS/Base.
• "Characteristic" is taken from the description of the literature to classify the natural compound.
• "Chemical Name" is the full chemical name in the literature including IUPAC name.
• "CAS Registry No." is CAS registry number.

NMR Measurement Conditions

• "Solvent" is the solvent for the measurement. If the solvent is not described, the data is empty. The specified conditions of temperature or pH are included.
• "¹H Frequency (MHz)" is the measuring frequency for ¹H NMR spectrum.
• "Shift Ref" is the chemical shift references for ¹H and ¹³C spectra given by authors. TMS is the internal reference of tetramethylsilane. The solvent shifts for the references were given in ppm unit for "¹H / ¹³C" shifts.

Others

• "NP No." is given for an organic natural compound. The same number is given if the spectra were measured by different solvents or different conformers.
• "Spectral Key" is the spectral key for carbon and proton NMR spectra. When the measuring conditions (like different solvents, temperatures and conformers) were different, a compound may have two or more Spectral keys.
• "Source" is the origins of the compound taken from.
• "Remarks" are taken from the authors' description concerning "Source".
• "Reference" is the literature from which the data are compiled.
• "Comments" are the compiler's comments.
• "Clear Errors in Assignment" may be corrected by compilers.

The distribution, by the carbon number, of the organic natural compounds compiled in CH-NMR-NP is shown in the graph below.

Organic compounds from SDBS-NMR

About 6,000 organic compounds are included from SDBS-NMR. The C-numbers are from 1 to 48 and about 70 % compounds are composed of C5 to C15, mainly from commercial sources. Most of the ¹H spectra were observed at 400 MHz. Since the digital spectral patterns were compiled, the view and download the spectral patterns are possible.

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