vamos-hose

A pure JavaScript library that predicts 13C NMR chemical shifts from SMILES strings. It generates HOSE codes and looks them up in a preprocessed NMRShiftDB2 database (1.4M entries). Runs entirely in the browser with no server-side dependencies — the database is code-split into 256 lazy-loaded chunks.

Live Demo · npm

Target API

lookupNmrShifts -- SMILES to predicted shifts

import { lookupNmrShifts } from 'vamos-hose';

const shifts = await lookupNmrShifts('CCCCC1=NC(Cl)=C(CO)N1CC2=CC=C(C=C2)C3=CC=CC=C3C4=NNN=N4', {
  nucleus: '13C',
});
// Returns: [{ shift: 13.9, atom: 'C', hose: '...', smiles: '...' }, ...]

plotSpectra -- Render a synthetic NMR spectrum

import { plotSpectra } from 'vamos-hose';

const canvas = document.getElementById('nmr-canvas');
plotSpectra(canvas, shifts, {
  range: [0, 220],    // ppm range
  width: 800,
  height: 300,
  lineWidth: 0.5,     // Lorentzian half-width in ppm
});

estimateFromSpectra -- Reverse lookup: peaks to candidate structures

import { estimateFromSpectra } from 'vamos-hose';

const candidates = await estimateFromSpectra({
  nucleus: '13C',
  peaks: [14.1, 22.7, 32.0, 127.5, 128.3, 130.6, 137.0, 174.1],
  tolerance: 2.0,     // ppm tolerance per peak
  minMatches: 5,      // minimum peaks that must match
});
// Returns: [{ smiles: '...', hose: '...', matchedPeaks: 7, score: 0.87 }, ...]

Development

npm install
npm test

Acknowledgments

This project builds on the work of several open-source projects and academic publications:

• nmrshiftdb2 — NMR chemical shift database (Stefan Kuhn, Christoph Steinbeck et al.). The HOSE code generator in src/hose-generator.js is a JavaScript port of the ExtendedHOSECodeGenerator (AGPL v3).
• CDK (Chemistry Development Kit) — The canonical labeling algorithm is ported from CDK's CanonicalLabeler (Oliver Horlacher, LGPL 2.1), which implements the Weininger algorithm (D. Weininger et al., J. Chem. Inf. Comput. Sci., 1989, 29, 97-101).
• openchemlib-js — SMILES parsing and molecule representation (BSD-3-Clause).
• W. Bremser — Original HOSE code concept (Analytica Chimica Acta, 1978, 103, 355-365).

License

AGPL-3.0-or-later

The HOSE code generator (src/hose-generator.js) is a JavaScript port of nmrshiftdb2's ExtendedHOSECodeGenerator, which is licensed under AGPL v3. It also ports CDK's CanonicalLabeler, licensed under LGPL 2.1. Since the algorithms were directly ported (not linked as a library), the derived code is a derivative work and the AGPL v3 copyleft applies to the entire project. See LICENSE and the src/hose-generator.js file header for details.

Note: The AGPL applies to the software only. Chemical shifts, NMR predictions, drug candidates, or any other scientific results produced by running this library are not covered by the AGPL and remain the property of the user.