Novel synthesis of methyl ketones based on the blaise reaction

Article abstract of DOI:10.1080/00397910802594276

A facile two-step synthesis of methyl ketones from alkyl nitriles via the Blaise conversion of nitriles into -keto esters and acid-mediated hydrolysis followed by decarboxylation of the resulting -keto esters is described. Copyright Taylor & Francis Group, LLC.

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Novel Synthesis of Methyl
Ketones Based on the Blaise
Reaction
H. Surya Prakash Rao a , K. Padmavathy a , K.
Vasantham a & Shaik Rafi a
a Department of Chemistry , Pondicherry University ,
Puducherry, India
Published online: 15 Apr 2009.
To cite this article: H. Surya Prakash Rao , K. Padmavathy , K. Vasantham & Shaik
Rafi (2009) Novel Synthesis of Methyl Ketones Based on the Blaise Reaction, Synthetic
Communications: An International Journal for Rapid Communication of Synthetic
Organic Chemistry, 39:10, 1825-1834, DOI: 10.1080/00397910802594276
To link to this article: http://dx.doi.org/10.1080/00397910802594276
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Synthetic Communications1, 39: 1825–1834, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802594276
Novel Synthesis of Methyl Ketones Based
on the Blaise Reaction
H. Surya Prakash Rao, K. Padmavathy,
K. Vasantham, and Shaik Rafi
Department of Chemistry, Pondicherry University, Puducherry, India
Abstract: A facile two-step synthesis of methyl ketones from alkyl nitriles via
the Blaise conversion of nitriles into b-keto esters and acid-mediated hydrolysis
followed by decarboxylation of the resulting b-keto esters is described.
Keywords: Blaise reaction, b-keto esters, methyl ketones
Apart from being synthetic intermediates,[1] many methyl ketones are
flavor and aroma substances.[2] Some methyl ketones are natural pro-
ducts resulting from decarboxylation of the corresponding fatty acids.[3]
A few lower-order methyl ketones are produced during cheese ripening.[4]
Reaction of methyl Grignard and related organometallic reagents with
acyl chlorides is a direct method generally employed for methyl ketone
synthesis.[5] Alternatively, the two-step reaction sequence of aldehydes
with methyl Grignard followed by oxidation of the resulting secondary
alcohols provides the methyl ketones. Overall, both methods use one-
carbon homologation of the corresponding aldehydes. Oxidation of the
terminal monosubstituted alkenes under Wacker–Tsuji conditions is also
used for methyl ketone synthesis.[6] These methods are limited by
availability of the required starting materials. We reasoned that alkyl
methyl ketones can be generated conveniently by dealkoxycarbonylation
of corresponding b-keto esters, which in turn, can be prepared readily by
Received August 20, 2008.
Address correspondence to H. Surya Prakash Rao, Department of Chemistry,
Pondicherry University, Puducherry, 605 014, India. E-mail: hspr.che@pondiuni.
edu.in
1825

1826
H. S. P. Rao et al.
the Blaise reaction on nitriles. The Blaise reaction is a classical reaction
used for the transformation of nitriles into b-keto esters or into enamino
esters by reacting with alkyl 2-bromoacetates and zinc.[7] Several modifi-
cations in the reaction conditions such as preactivation of zinc and use of
ultrasound make the reaction facile and useful in organic synthesis.[8]
Overall, the Blaise conversion of nitriles into corresponding b-keto esters
is a two-carbon homologation.[9] By converting the product b-keto esters
into corresponding methyl ketones, the scope of the Blaise reaction can
be extended for one-carbon homologation of nitriles. We report herein
a facile and easy protocol for the generation of methyl ketones 3 from
nitriles 1 via b-keto esters 2 in a two-step process (Scheme 1).
The transformation of heptanenitrile 1b into 2-octanone 3b was
taken as a test case to optimize reaction conditions and yields. When
Blaise transformation of heptanenitrile 1b into ethyl 3-oxononanoate
2b was attempted by using 2 equivalents of ethyl 2-bromoacetate and
2 equivalents of zinc, activated according to the procedure described by
Hannick and Kishi,[8a] the reaction proceeded to give the b-keto ester
2b in only 40% yield. The yield of 2b increased to 67% when 1 mol% of
trimethylsilyl chloride (TMSCl) was employed for zinc activation.[10] By
using 10 mol% of TMSCl, the yield could be raised to 86% (Scheme 1
and Table 1). We found that the transformation works well under opti-
mized conditions on a 0.1-mol scale by employing benchtop commercial-
grade zinc powder and tetrahydrofuran (THF). The reaction, however,
required 2 equivalents of zinc and ethyl bromoacetate for completion.
Generality of the Blaise transformation was ascertained by reacting
various alkyl nitriles 1a–h with ethyl 2-bromoacetate to provide b-keto
esters 2a–h in excellent yield (Scheme 1 and Table 1). The 1H NMR spec-
tra of the b-keto esters 2a–h revealed the presence of enol tautomers to an
extent of 13%.
Hydrolysis of the ester group in the b-keto esters 2a–h followed by
decarboxylation of the resulting b-keto acids was conducted in a one-pot
operation with aqueous 18 N H2SO4 and 1% v=v polyethylene glycol-400
(PEG-400) under reflux conditions to provide methyl ketones 3a–h in
Scheme 1. 1a, 2a, 3a: R ¼ CH3(CH2)2CH2; 1b, 2b, 3b: R ¼ CH3(CH2)5CH2; 1c,
2c, 3c: R ¼ CH3(CH2)10CH2; 1d, 2d, 3d: R ¼ CH3(CH2)12CH2; 1e, 2e, 3e: R ¼ CH3-
(CH2)16CH2: 1f, 2f, 3f: R ¼ C6H5CH2; 1g, 2g, 3g: R ¼ CH3(CH2)2CH2SCH2CH2;
1h, 2h, 3h: R ¼ CH3(CH2)6CH2SCH2CH2.

1827

1828

Novel Synthesis of Methyl Ketones
1829
moderate to good yield (Scheme 1 and Table 1). The methyl ketones 3a–h
displayed the characteristic singlet for the methyl group at about d 2.1 ppm
in their H NMR spectra. Conversion of 1g and 1h into corresponding
1
methyl ketones 3g and 3h demonstrates tolerance of sulfur as a part of
the chain. Even though some of the methyl ketones prepared in study,
such as 3g and 3h, can be prepared alternatively by Michael addition of
corresponding thiols to methyl vinyl ketone,[11] the present procedure is
versatile and can be used for the preparation of many other alkyl methyl
ketones from readily available starting materials and benchtop reagents.
Efficacy of the present method was demonstrated by facile Blaise
conversion of the bis-nitrile 4 into the diketone 6 (Scheme 2). Addition
of 1,2-ethanedithiol to acrylonitrile provided the bis-nitrile 4. The Blaise
conversion of bis-nitrile 4 with ethyl bromoacetate and zinc activated by
TMSCl furnished bis-b-keto ester 5 in nearly quantitative yield. Dilute
sulfuric acid–mediated hydrolysis of the two-ester groups in 5 followed
by decarboxylation furnished known[12] C2 symmetric diketone 6 in
moderate yield.
In conclusion, we have demonstrated an efficient and facile conver-
sion of nitriles into corresponding methyl ketones in a two-step protocol
by going through the Blaise reaction for generating b-keto esters in the
firststep and subsequent acid-mediated dealkoxycarbonylation in the
secondstep.
EXPERIMENTAL
General
The 1H NMR spectra were recorded in CCl4 on a Jeol MY 60-MHz FT-
NMR spectrometer using tetramethylsilane (TMS, 0 ppm) as an internal
Scheme 2.

1830
H. S. P. Rao et al.
standard. Infrared (IR) spectra were obtained on an ABB BOMEM
MB 104 Fourier transform–infrared (FT-IR) spectrometer. Mass spectra
(MS) were obtained using a Varian gas chromatography (GC)-MS spec-
trometer. The nitriles 1a–d were prepared from the corresponding alkyl
bromides by treatment with sodium cyanide.[13] The nitrile 1e is commer-
cially available. The nitriles 1f and 1g were prepared by conjugate addi-
tion of butanethiol or octanethiol to acrylonitrile in chloroform in the
presence of a catalytic amount (3 mol%) of triethylamine.[14] Among
the b-keto esters prepared in this study, ethyl 3-oxoheptanoate 2a,[15]
ethyl 3-oxononanoate 2b,[16] ethyl 3-oxopentadecanoate 2c,[17] ethyl
3-oxoheptadecanoate 2d,[18] ethyl 3-oxohenicosanoate 2e,[19] ethyl 3-oxo-
4-phenylbutanoate 2f,[20] and ethyl 3-oxo-5-butylsulphanylpentanoate
2g[21] are known compounds. Similarly, all the methyl ketones prepared
in this study [viz., 2-hexanone 3a,[22] 2-octanone 3b,[23] 2-tetradecanone
3c,[24] 2-hexadecanone 3d,[25] 2-icosanone 3e,[26] 1-phenyl-2-propanone
3f,[27] 4-butylsulphanylbut-2-one 3g,[28] 4-octylsulphanylbut-2-one 3h,[24]
and 4-(2-[(3-oxobutyl)sulfanyl]ethylsulfanyl)-2-butanone 6[12]] are known
compounds. Their physical and spectral (IR, 1H NMR, and EI-MS) data
matched the reported data. Spectral and other characterization details
are given for two unknown b-keto esters 2h and 5 as well as for 2e, for
which complete data are not available.
Representative Procedure for Conversion of Alkylnitriles 1a–g to
b-Keto Esters 2a–g
TMSCl (0.25 g, 2.32 mmol, 10 mol% of Zn) was added to a stirred suspen-
sion of zinc (1.52 g, 23.20 mmol) in THF (8 mL) taken in a 100-mL
round-bottomed flask under reflux, and the mixture was refluxed for
30 min. To the cooled reaction mixture, ethyl 2-bromoacetate (0.33 g,
1.98 mmol) was added. After the appearance of the green color, nitrile
(0.96 g, 11.60 mmol) and the remaining ethyl 2-bromoacetate (3.52 g,
21.08 mmol) were added simultaneously using two dropping funnels.
Progress of the reaction was monitored by thin-layer chromatography
(TLC). After 4 h, aq 3N HCl (4 mL) was added dropwise to the cooled
(0–5ꢀC) reaction mixture and stirred for 1 h at room temperature, by
which time the two phases separated. The organic phase (THF) was
separated, and the remaining aqueous layer was diluted with ice-cold
water (50 mL). The aqueous layer was extracted with dichloromethane
(3 ꢁ 15 mL) in portions. The combined organic layer was dried over
anhydrous Na2SO4 and concentrated in vacuo to yield the crude product.
Column chromatography (hexanes–EtOAc, 9:1) of the residue afforded
the b-keto esters in 84–93% yield.

Novel Synthesis of Methyl Ketones
1831
Data
Ethyl 3-Oxohenicosanoate 2e
White solid (85%); mp: 47–48ꢀC; IR (KBr): nmax 2924, 2854, 1751
(COOEt), 1719 (CO), 1647, 1462, 1312, 1233, 1024 cmꢂ1 1H NMR
;
(60 MHz, CCl4): d 0.89–1.60 (m, 12H), 2.07–2.27 (m, 2 H), 3.43 (s, 2H,
-CO-CH2-CO-), 4.03 (q, J ¼ 7.2 Hz, 2H, OCH2CH3). HRMS (ESI) calcu-
lated for C23H44O3Na (MNaþ): 391.3188; found: 391.3192.
Ethyl 3-Oxo-5-octylsulphanylpentanoate 2h
Colorless viscous oil (84%); IR (neat): nmax 2926, 2855, 1742 (COOEt),
1
1721 (CO), 1456, 1406, 1312, 1179 cmꢂ1; H NMR (60 MHz, CCl4): d
0.89 (t, J ¼ 7.1 Hz, 3H), 1.0–1.8 (m, 15H), 2.1–2.9 (m, 6H), 3.34 (s, 2H,
-CO-CH2-CO-), 4.17 (q, J ¼ 7.2 Hz, 2H, OCH2CH3). HRMS (ESI)
calculated for C15H28O3SNa (MNaþ): 311.1657; found: 311.1662.
Ethyl 5-[(2-[5-(ethyloxy)-3,5-dioxopentyl]sulfanylethyl)sulfanyl]-3-
oxopentanoate 5
Yellow viscous oil (93%); IR (neat): nmax 2984, 2927, 1744 (COOEt), 1713
1
(CO), 1638, 1412, 1319, 1174, 1030 cmꢂ1; H NMR (60 MHz, CCl4): d
1.28 (t, J ¼ 7.2 Hz, 6H), 2.74 (m, 12H), 3.47 (s, 4H, -CO-CH2-CO-),
4.21 (q, J ¼ 7.2 Hz, 4H, OCH2CH3). HRMS (ESI) calculated for
C16H26O6S2Na (MNaþ): 401.1068; found: 401.1073.
Representative Procedure for Preparation of Alkan-2-ones 3a–g
PEG-400 (0.015 mL) was added to a stirred suspension of b-keto ester
(0.002 mol) in 18 N sulfuric acid in water (1.5 mL), and the reaction mix-
ture was refluxed vigorously for 2–4 h. Then, it was cooled to 0–5ꢀC,
diluted with ice-cold water (20 mL), and extracted with dichloromethane
(3 ꢁ 15 mL). The combined organic layer was dried over anhydrous
Na2SO4 and concentrated in vacuo to yield the crude product. Silica-gel
column chromatography (hexanes–EtOAc, 9:1) of the residue afforded
the methyl ketones in 40–74% yield.
ACKNOWLEDGMENTS
H. S. P. R. thanks the University Grants Commission (UGC) for
UGC-SAP, the Council of Scientific and Industrial Research (CSIR) for

1832
H. S. P. Rao et al.
major research project, and the Department of Science and Technology
(DST) for the FIST program. K. V. thanks CSIR for junior and senior
fellowships.
REFERENCES
1. (a) Kimball, D. B.; Silks III, L. A. Current progress in the acetate=methyl
ketone aldol reaction. Curr. Org. Chem. 2006, 10, 1975–1992; (b) Carballeira,
N. M. Recent developments in the total synthesis of bioactive marine fatty
acids. In Studies in Natural Products Chemistry; Atta-ur-Rahman (Ed.);
Elsevier Science, 2002; vol. 26, pp. 63–94; (c) Holland, H. L. Microbial trans-
formations. Curr. Opin. Chem. Biol. 1998, 2, 77–84.
2. (a) Atteaga, S.; Andre-Cetto, A.; Cardenas, R. Fragrances: Larrea tridentata
(Creosote bush), an abundant plant of Mexican and US-American deserts
and its metabolite nordihydroguaiaretic acid. J. Ethnopharmacol. 2005, 98,
231–239; (b) Sharma, R.; Chisti, Y.; Banerjee, U. C. Flavors: Production,
purification, characterization, and applications of lipases. Biotechnol. Adv.
2001, 1, 627–662; (c) Jarolim, V.; Hejno, K.; Sehnal, F.; Sorm, F. Phero-
mones: Natural and synthetic materials with insect hormones activity 8: Juve-
nile activity of the farnesane-type compounds. Life Sci. 1969, 8, 831–841.
3. (a) Dervisoglu, M.; Yazici, F. Ripening changes of Kulek cheese in wooden
and plastic containers. J. Food Eng. 2001, 48, 243–249; (b) Aogyagi, F.;
Maeno, S.; Okuno, T.; Matsumoto, H.; Ikura, M.; Kikichi, K.; Matsumoro,
T. Gymnopilins, bitter principles of the big-laughter mushroom. Tetrahedron
Lett. 1983, 24, 1991–1994.
´
4. (a) Barrona, L. J. R.; Redondo, Y.; Aramburub, M.; Gilb, P.; Perez-
Elortondob, F. J.; Albisub, M.; Ana, I.; Najeraa, A. I.; de Renobalesc, M.;
ꢀ
ꢀ
´
Fernandez-Garcıa, E. Volatile composition and sensory properties of indust-
rially produced Idiazabal cheese. Int. J. Dairy Technol. 2007, 17, 1401–1414;
(b) Forney, F. W.; Markovetz, A. J. The biology of methyl ketones. J. Lipid
Res. 1971, 12, 383–395.
5. Dieter, R. K. Reaction of acyl chlorides with organometallic reagents: A ban-
quet table of metals for ketone synthesis. Tetrahedron 1999, 55, 4177–4236.
6. (a) Nishimura, T.; Uemura, S. Novel palladium catalytic systems for organic
transformations. Synlett. 2004, 201–216; (b) Tsuji, J.; Mandai, T. Simple
synthesis of diplodialides from a butadiene telomer. Tetrahedron Lett. 1978,
19, 1817–1820.
7. (a) Blaise, E. E. New reactions of organometallic derivatives, II: a-Alkyl
b-keto ethers. C. R. Hebd. Seances Acad. Sci. 1901, 132, 478–480; (b) Blaise,
E. E. New reactions of organometallic derivatives, III: Unsubstituted
b-ketonic esters. C. R. Hebd. Seances Acad. Sci. 1901, 132, 978–980; (c) Blaise,
E. E.; Courtot, A. Abnormal dehydrations of the alkyloxypivalinic acid ester,
II: Rearrangements of the alkyl and carboxyl group. Bull. Soc. Chim. Fr. 1906,
35, 589–600; (d) Lee, J. J. Name Reactions: A Collection of Detailed Reaction
Mechanisms, 3rd ed. Springer Verlag: Berlin, 2006; p. 37.

Novel Synthesis of Methyl Ketones
1833
8. (a) Hannick, S. M.; Kishi, Y. An improved procedure for the Blaise reac-
tion: A short, practical route to the key intermediates of the saxitoxin synth-
esis. J. Org. Chem. 1983, 48, 3833–3835; (b) Lee, A. S.; Cheng, R. Y. A
simple and highly efficient synthesis of b-amino-a,b-unsaturated esters via
sonochemical Blaise reaction. Tetrahedron Lett. 1997, 38, 443–446; (c) Shin,
H.; Choi, B. S.; Lee, K. K.; Choi, H.-W.; Chang, J. H.; Lee, K. W.; Nam,
D. H.; Kim, N.-S. Efficient activation of zinc: Application of the Blaise
reaction to an expedient synthesis of a statin intermediate. Synthesis.
2004, 16, 2629–2632.
9. (a) Hoang, C. T.; Alezra, V.; Guillot, R.; Kouklovsky, C. A. Stereoselective
entry into functionalized 1,2-diamines by zinc-mediated homologation of
ꢁ
ꢀ
a-amino acids. Org. Lett. 2007, 9, 2521–2524; (b) Pospisil, J.; Marko, I. E.
Total synthesis of jerangolid D. J. Am. Chem. Soc. 2007, 129, 3516–3517.
10. Picotin, G.; Miginiac, P. Activation of zinc by trimethylchlorosilane: An
improved procedure for the preparation of b-hydroxy esters from ethyl
bromoacetate and aldehydes or ketones (Reformatsky reaction). J. Org.
Chem. 1987, 52, 4796–4798.
11. Khatik, G. L.; Kumar, R.; Chakraborti, A. K. Catalyst-free conjugated
addition of thiols to a,b-unsaturated carbonyl compounds in water. Org.
Lett. 2006, 8, 2433–2436.
12. Firouzabadi, H.; Iranpoor, N.; Jafari, A. A. H3PW12O40 as a useful
recyclable heterogeneous catalyst for the facile and highly efficient
Michael addition reaction of thiols to a,b-unsaturated ketones. Synlett
2005, 299–303.
13. Vogel, A. I.; Tatchell, A. R.; Furnis, B. S.; Hannaford, A. J.; Smith, P. W. G.
Vogel’s Textbook of Practical Organic Chemistry, 5th ed.; Prentice Hall: New
Delhi, 1996; pp. 712–714.
14. Bakuzis, P.; Bakuzis, M. L. F. Oxidative functionalization of the b-carbon in
a,b-unsaturated systems: Preparation of 3-phenylthioenones, acrylates, and
other vinyl derivatives. J. Org. Chem. 1981, 46, 235–239.
15. Nguyen, V. T. H.; Esen, B.; Bettina, A.; Peter, L. Synthesis of 4-alkyl- and
4-(x-chloroalkyl)-3-hydroxy-5-alkylidenebutenolides based on cyclizations
of 4-alkyl- and 4-(x-chloroalkyl)-1,3-bis(trimethylsilyloxy)buta-1,3-dienes
with oxalyl chloride. Synthesis. 2006, 2865–2872.
16. Liao, M.; Wang, J. CuSO4-catalyzed diazo decomposition in water: A prac-
tical synthesis of b-keto esters. Tetrahedron Lett. 2006, 47, 8859–8861.
17. Beijer, F. H.; Sijbesma, R. P.; Vekemans, J. A. J. M.; Meijer, E. W.;
Kooijman, H.; Spek, A. L. Hydrogen-bonded complexes of diaminopyridines
and diaminotriazines. J. Org. Chem. 1996, 61, 6371–6380.
18. Mai, A.; Rotili, D.; Tarantino, D.; Ornaghi, P.; Tosi, F.; Vicidomini, C.;
Sbardella, G.; Nebbioso, A.; Miceli, M.; Altucci, L.; Filetici, P. Small-
molecule inhibitors of histone acetyltransferase activity: Identification and
biological properties. J. Med. Chem. 2006, 49, 6897–6907.
19. Tachibana, K. K.; Ishii, Y. F. Silver halide color photographic light-sensitive
material containing pyrazoloazole type cyan coupler. European patent
EP19870310417, filed November 25, 1987.

1834
H. S. P. Rao et al.
20. Terai, T.; Kikuchi, K.; Iwasawa, S.-Y.; Kawabe, T.; Hirata, Y.; Urano, Y.;
Nagano, T. Modulation of luminescence intensity of lanthanide complexes
by photoinduced electron transfer and its application to a long-lived protease
probe. J. Am. Chem. Soc. 2006, 128, 6938–6946.
21. Ireland, R.; Brown, F. R. Jr. Macrocyclic lactone formation through
sulfide contraction: Synthesis of (ꢃ)-diplodialide A. J. Org. Chem. 1980,
45, 1868–1880.
22. Qian, W.; Jin, E.; Bao, W.; Zhang, Y. Clean and selective oxidation of
alcohols catalyzed by ion-supported TEMPO in water. Tetrahedron. 2006,
62, 556–562.
´
ꢀ
23. Miranda, P. O.; Dıaz, D. D.; Padron, J. I.; Miguel, A.; Ramırez, M. A.;
Martın, V. S. Fe(III) halides as effective catalysts in carbon–carbon bond
´
´
formation: Synthesis of 1,5-dihalo-1,4-dienes, a,b-unsaturated ketones, and
cyclic ethers. J. Org. Chem. 2005, 70, 57–62.
24. Mitsudo, K.; Kaide, T.; Nakamoto, E.; Yoshida, K.; Tanaka, H. Electro-
chemical generation of cationic Pd catalysts and application to Pd=TEMPO
TEMPO double-mediatory electrooxidative Wacker-type reactions. J. Am.
Chem. Soc. 2007, 129, 2246–2247.
25. Villemin, D.; Hammadi, M.; Hachemi, M. Supported metalated phthalo-
cyanine as catalyst for oxidation by molecular oxygen: Synthesis of quinones
and carbonyl compounds. Synth. Commun. 2002, 32, 1501–1515.
26. Pangborn, M. C.; Anderson, R. J. The chemistry of the lipids of Tubercle
bacilli, XLI, part 1: The composition of the Timothy bacillus wax; part 2:
The isolation of d-eicosanol-2 and d-octadecanol-2 from the unsaponifiable
matter of the Timothy bacillus wax. J. Am. Chem. Soc. 1936, 58, 10–14.
27. Singh, A. K.; Khade, P. K. Anthracene-9-methanol—A novel fluorescent
phototrigger for biomolecular caging. Tetrahedron Lett. 2005, 46, 5563–5566.
28. Sabirov, S. S.; Gnevasheva, L. M.; Ismailov, M. I.; Isobaev, M. D. Synthesis
of mono (alkylthio)-substituted ketones. Zh. Org. Khim. 1984, 20, 1362–1366;
CAN 1984, 101, 211017.