Retinal

Athanor · official

C₂₀H₂₈O · 284.4 g/mol

IUPAC name: (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraenal

Also called vitamin A aldehyde, retinaldehyde, vitamin A, rhodopsin chromophore

Vitamins

Open in Athanor

Drawn from its SMILES with RDKit

DangerHarmful if swallowed · Causes skin irritation · May damage fertility or the unborn child · May cause long lasting harmful effects to aquatic life

Names and identifiers

IUPAC name: (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraenal
Synonyms: vitamin A aldehyde, retinaldehyde, vitamin A
+ 37 more
rhodopsin chromophore, all-trans-Retinal, trans-Retinal, retinene, axerophthal, all-E-Retinal, E-Retinal, Retinene 1, all-trans-Retinaldehyde, Vitamin A1 aldehyde, all-trans-Vitamin A aldehyde, all-trans-Retinene, Retinyl aldehyde, Retinal, all-trans, (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraenal, (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraenal, DTXSID5025998, CHEBI:17898, RR725D715M, NSC626581, NSC-122757, NSC-626581, DTXCID205998, NSC122757, 3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-Nonatetraenal, 3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexenyl)nona-2,4,6,8-tetraenal, CHEBI:15035, Retinyl Aldehydde, All trans retinal, Aldehydde, Retinyl, 11 cis Retinal, 11 trans Retinal, Aldehyde, Vitamin A, RefChem:879480, 204-135-8, all trans-Retinal, all-trans retinal
Molecular formula: C₂₀H₂₈O
Empirical formula: C₂₀H₂₈O
Molecular weight: 284.4 g/mol
Exact mass: 284.21402
CAS number: 116-31-4
PubChem CID: 638015
Canonical SMILES: CC1=C(C(CCC1)(C)C)C=CC(=CC=CC(=CC=O)C)C
Isomeric SMILES: CC1=C(C(CCC1)(C)C)/C=C/C(=C/C=C/C(=C/C=O)/C)/C
InChI: InChI=1S/C20H28O/c1-16(8-6-9-17(2)13-15-21)11-12-19-18(3)10-7-14-20(19,4)5/h6,8-9,11-13,15H,7,10,14H2,1-5H3/b9-6+,12-11+,16-8+,17-13+
InChIKey: NCYCYZXNIZJOKI-OVSJKPMPSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Calculated

Heavy atoms: 21
Rings: 1
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.45
H-bond donors: 0
H-bond acceptors: 1
Rotatable bonds: 5
TPSA (Å²): 17.1
Formal charge: 0
XLogP3: 6.2 PubChem
Complexity: 522 PubChem
Stereocenters: None
Double-bond geometry: C10=C11: E · C12=C14: E · C15=C16: E · C17=C19: E
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C84.45%
H9.92%
O5.62%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 5.72 Crippen (Wildman and Crippen 1999)
log S (water solubility): -4.88 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 3.26 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 284.44
log P ≤ 5 (Crippen): 5.72
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 1

Breaks 1 of the four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Most widely reported: 147 company reports to ECHA. Source [1].

Harmful or irritant
Health hazard

H302Harmful if swallowed (28.6% of reports)
H315Causes skin irritation (29.3% of reports)
H360May damage fertility or the unborn child (72.1% of reports)
H413May cause long lasting harmful effects to aquatic life (72.1% of reports)

Precautionary statements: P203, P264, P270, P273, P280, P301+P317, P302+P352, P318, P321, P330, P332+P317, P362+P364, P405, P501

Safety data sheets on the supplier’s page: 001Chemical, Finetech Industry Limited, AA BLOCKS.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[2]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[3]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[4]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[5]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[6]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
[7]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.