:2-Methylundecanal

{{Chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 477214720

| ImageFile = 2-methylundecanal 200.svg

| ImageName = Skeletal formula of 2-methylundecanal

| PIN = 2-Methylundecanal{{Cite web|title = 2-Methylundecanal - Compound Summary|url = https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=61031|work = PubChem Compound|publisher = National Center for Biotechnology Information|accessdate = 12 October 2011|location = USA|date = 26 March 2005|at = Identification and Related Records}}

|Section1={{Chembox Identifiers

| CASNo = 110-41-8

| CASNo_Ref = {{cascite|correct|CAS}}

| ChEMBL = 3182849

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = S94QNS2VY5

| PubChem = 61031

| PubChem1 = 6915922

| PubChem1_Comment = (2R)-2-methyl

| PubChem2 = 637522

| PubChem2_Comment = (2S)-2-methyl

| ChemSpiderID = 54990

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID1 = 5291693

| ChemSpiderID1_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID1_Comment = (2R)-2-methyl

| ChemSpiderID2 = 553128

| ChemSpiderID2_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID2_Comment = (2S)-2-methyl

| EINECS = 203-765-0

| RTECS = YQ1509000

| SMILES = CCCCCCCCCC(C)C=O

| StdInChI = 1S/C12H24O/c1-3-4-5-6-7-8-9-10-12(2)11-13/h11-12H,3-10H2,1-2H3

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| InChI = 1/C12H24O/c1-3-4-5-6-7-8-9-10-12(2)11-13/h11-12H,3-10H2,1-2H3

| StdInChIKey = NFAVNWJJYQAGNB-UHFFFAOYSA-N

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| InChIKey = NFAVNWJJYQAGNB-UHFFFAOYAB

}}

|Section2={{Chembox Properties

| C=12 | H=24 | O=1

| Appearance = Colourless liquid

| Density = 830.3 mg cm⁻³

| BoilingPtK = 444

| RefractIndex = 1.432

}}

|Section3={{Chembox Hazards

| FlashPtC = 93.4

| GHSPictograms = {{GHS07}}{{GHS09}}

| GHSSignalWord = Warning

| HPhrases = {{H-phrases|315|317|410}}

| PPhrases = {{P-phrases|261|264|272|273|280|302+352|305+351+338|321|332+313|333+313|337+313|362|363|391|501}}

}}

|Section4={{Chembox Related

| OtherFunction_label = alkyl aldehydes

| OtherFunction = Hexyl cinnamaldehyde

Isobutyraldehyde

Lilial

}}

2-Methylundecanal is an organic compound that is found naturally in kumquat peel oil.{{cite book | last = Fenorali | first = Giovanni | year = 2004 | title = Fenorali's Handbook of Flavor Ingredients | edition = 5th | location = Boca Raton | publisher = CRC Press }} This compound smells herbaceous, orange, and ambergris-like.[http://www.chm.bris.ac.uk/motm/chanel5/c5jm.htm Molecule of the Month: Chanel No 5 and 2-methylundecanal] At high dilution it has a flavor similar to honey and nuts. It is a colorless or pale yellow liquid that is soluble in organic solvents such as ether and ethanol.{{cite book | year = 2008–2009 | title = CRC Handbook of Chemistry and Physics | edition = 89th | publisher = CRC Press }} It is used as a fragrance component in soaps, detergents, and perfumes.

Preparation

The first synthesis of 2-methylundecanal was recorded by Georges Darzens in 1904 from methyl nonyl ketone and ethyl chloroacetate.{{cite book | last = Darzens | first = Georges | year = 1904 | title = Comptes Rendus Hebdomadaires des séances de l'Académie des Sciences }} This method of synthesis can be used to produce a variety of aldehydes and became known as the Darzens reaction and is still used today. 2-Methylundecanal is synthesized in industry by two main routes. The first route, like Darzens, involves converting methyl nonyl ketone to its glycidate by allowing it to react with alkyl chloroacetate. The glycidate then undergoes saponification followed by decarboxylation.{{cite book | year = 2009 | title = Ullmann's Encyclopedia of Industrial Chemistry | edition = 7th | location = Hoboken | publisher = John Wiley & Sons Inc. }}

:CH₃(CH₂)₈C(O)CH₃ + ClCH₂CO₂R → CH₃(CH₂)₈CH(CH₃)OCH(CO₂R) + HCl

:CH₃(CH₂)₈CCH₃OCCO₂R + H₂O → CH₃(CH₂)₈CH(CH₃)CHO + CO₂ + ROH

The second method for the synthesis of 2-methylundecanal begins with the conversion of undecanal to 2-methyleneundecanal by allowing it to react with formaldehyde in the presence of base. The 2-methyleneundecanal is then hydrogenated to give 2-methylundecanal. The resulting solution is over 50% 2-methyleneundecanal. The double bond of this compound is hydrogenated and the resulting 2-methylundecanal is separated from the by-products using fractional distillation. The required undecanal in the first step is generated from 1-decene by hydroformylation.

:CH₃(CH₂)₇CH₂=CH₂ + H₂ + CO → CH₃(CH₂)₁₀CHO

:CH₃(CH₂)₁₀CHO + HCHO → CH₃(CH₂)₈C(CH₂)CHO + H₂O

:CH₃(CH₂)₈C(CH₂)CHO + H₂ → CH₃(CH₂)₈CH(CH₃)CHO

Chirality

2-Methylundecanal contains one asymmetric carbon atom.

File:2-Methylundecanal Structural Formulae of both Enantiomers.png

The enantiomers can be synthesized with high enantiomeric purity using the SAMP/RAMP hydrazone method. This process involves starting with simple achiral aldehydes and converting them either to their SAMP or RAMP chiral hydrazones using SAMP or RAMP as a chiral auxiliary. The chiral hydrazones are then metalated with lithium diisopropylamide (LDA) and alkylated with a slight excess of dimethyl sulfate. Testing of the enantiomers by a professional perfumer indicated only a slight difference in odor quality and intensity.{{cite book | last = Dyker | first = Hubert | year = 1990 | title = Synthesis and Properties of Enantiomers of the Two Artificial Fragrances Lilial and Methylundecanal }}

Applications

2-Methylundecanal is used widely as a fragrance element in soaps and detergents as well as in the perfume industry to give conifer notes, fir in particular, but is also used in fantasy compositions. This aldehyde was one of the first synthetics to be used in a prestigious perfume, namely Chanel No. 5.{{cite book | last = Ramsden | first = E.N. | year = 2000 | title = A-Level Chemistry | edition = 4th | location = UK | publisher = Nelson Thornes }}

References

External links

[http://www.chm.bris.ac.uk/motm/chanel5/c5jm.htm Molecule of the Month: Chanel No 5 and 2-methylundecanal]