A Green Chemistry Method for the Regeneration of Carbonyl Compounds from Oximes by Using Cupric Chloride Dihydrate as a Recoverable Promoter for Hydrolysis

Abstract

A mild, efficient, general, and green method for the regeneration of carbonyl compounds from their corresponding oximes is described. Cupric salts promoted hydrolysis of oximes was studied, and the best reaction conditions for the hydrolysis have been found. Carbonyl compounds were obtained in 85-98% yields after the treatment of oximes with 2 molar equivalent of CuCl₂˙2H₂O at reflux (around 75 ˚C) in a mixed solvent of acetonitrile and water (4:1). In addition, cupric salt was readily recovered in an almost quantitative yield via the complete precipitation of Cu(OH)₂˙2H₂O.

carbonyl compounds - oxime - hydrolysis - cupric chloride - green chemistry

References and Notes

1a Corsaro A. Chiacchio MA. Pistara V. Curr. Org. Chem.  2009,  13:  482 

1b Corsaro A. Chiacchio U. Pistara V. Synthesis  2001,  1903 

2 Greene TW. Wuts PGM. Protective Groups in Organic Synthesis   3rd ed.:  John Wiley; New York: 1999. 

3 Shriner RL. Fuson RC. Curtin DY. Morrill TC. The Systematic Identification of Organic Compounds   6th ed.:  John Wiley; New York: 1980. 

4a Wang K. Qian X. Cui J. Tetrahedron  2009,  65:  10377 

4b Domingo LR. Picher MT. Arroyo P. Sez JA. J. Org. Chem.  2006,  71:  9319 

4c Czekelius C. Carreira EM. Angew. Chem. Int. Ed.  2005,  44:  612 

4d Kabalka GW. Pace RD. Wadgaonkar PP. Synth. Commun.  1990,  20:  2453 

4e Baran J. Mayr H. J. Org. Chem.  1989,  54:  5012 

4f Barton DH. Beaton JM.
J. Am. Chem. Soc.  1961,  83:  4083 

4g Barton DHR. Beaton JM. Geller LE. Pechet MM. J. Am. Chem. Soc.  1961,  83:  4076 

5a De S K. Tetrahedron Lett.  2003,  44:  9055 

5b Shirini F. Zolfigol MA. Safari A. Mohammadpoor-Baltork I. Mirjalili BF. Tetrahedron Lett.  2003,  44:  7463 

5c Shirini F. Zolfigol MA. Mallakpour B. Mallakpour SE. Hajipour AR. Baltork IM. Tetrahedron Lett.  2002,  43:  1555 

5d Lee SY. Lee BS. Lee C.-W. Oh DY.
J. Org. Chem.  2000,  65:  256 

5e Curini M. Rosati O. Pisani E. Costantino U. Synlett  1996,  333 

5f Ranu BC. Sarkar DC. J. Org. Chem.  1988,  53:  878 

5g Donaldson RE. Saddler JC. Byrn S. McKenzie AT. Fuchs PL. J. Org. Chem.  1983,  48:  2167 

5h Cava MP. Little RL. Napier DR. J. Am. Chem. Soc.  1958,  80:  2257 

6a Majireck MM. Witek JA. Weinreb SM. Tetrahedron Lett.  2010,  51:  3555 

6b Martin M. Martinez G. Urpi F. Vilarrasa J. Tetrahedron Lett.  2004,  45:  5559 

6c Lukin KA. Narayanan BA. Tetrahedron  2002,  58:  215 

6d Watanabe Y. Morimoto S. Adachi T. Kashimura M. Asaka T. J. Antibiot.  1993,  46:  647 

6e Akazome M. Tsuji Y. Watanabe Y. Chem. Lett.  1990,  635 

6f Curran DP. Brill JF. Rakiewicz DM. J. Org. Chem.  1984,  49:  1654 

6g Barton DHR. Motherwell WB. Simon ES. Zard SZ. J. Chem. Soc., Chem. Commun.  1984,  337 

6h Olah GA. Arvanaghi M. Prakash GKS. Synthesis  1980,  220 

6i Pojer PM. Aust. J. Chem.  1979,  32:  201 

6j Timms GH. Wildsmith E. Tetrahedron Lett.  1971,  12:  195 

6k Corey EJ. Richman JE. J. Am. Chem. Soc.  1970,  92:  5276 

6l Pines SH. Chemerda JM. Kozlowski MA. J. Org. Chem.  1966,  31:  3446 

Numerous methods for the oxidative deoximation have been reported, recent examples are as follows:

7a Zhou X.-T. Yuan Q.-L. Ji H.-B. Tetrahedron Lett.  2010,  51:  613 

7b Shaabani A. Farhangi E. Appl. Catal., A  2009,  371:  148 

7c Ganguly NC. Barik SK. Synthesis  2008,  425 

7d Gupta PK. Manral L. Ganesan K. Synthesis  2007,  1930 

7e Gogoi P. Hazarika P. Konwar D. J. Org. Chem.  2005,  70:  1934 

7f Shaabani A. Naderi S. Rahmati A. Badri Z. Darvishi M. Lee DG. Synthesis  2005,  3023 

7g Khazaei A. Manesh AA. Synthesis  2005,  1929 

7h Jain N. Kumar A. Chauhan SMS. Tetrahedron Lett.  2005,  46:  2599 

7i Li Z. Ding R.-B. Xing Y.-L. Shi S.-Y. Synth. Commun.  2005,  35:  2515 

7j Khazaei A. Manesh AA. Synthesis  2004,  1739 

7k Yang Y. Zhang D. Wu L.-Z. Chen B. Zhang L.-P. Tung C.-H. J. Org. Chem.  2004,  69:  4788 

7l Arnold JN. Hayes PD. Kohaus RL. Mohan RS. Tetrahedron Lett.  2003,  44:  9173 

7m Krishnaveni NS. Surendra K. Nageswar YVD. Rao KR. Synthesis  2003,  1968 

7n Narsaiah AV. Nagaiah K. Synthesis  2003,  1881 

7o Bose DS. Reddy AVN. Das APR. Synthesis  2003,  1883 

7p Chandrasekhar S. Gopalaiah K. Tetrahedron Lett.  2002,  43:  4023 

7q Khazaei A. Vaghei RG. Tetrahedron Lett.  2002,  43:  3073 

7r Hosseinzadeh R. Tajbakhsh M. Niaki MY. Tetrahedron Lett.  2002,  43:  9413 

7s Blay G. Benach E. Fernandez I. Galletero S. Pedro J. Ruiz R. Synthesis  2000,  403 

8a Chavan SP. Soni P. Tetrahedron Lett.  2004,  45:  3161 

8b Maynez SR. Pelavin L. Erker G. J. Org. Chem.  1975,  40:  3302 

8c DePuy CH. Ponder BW. J. Am. Chem. Soc.  1959,  81:  4629 

8d Hershberg EB. J. Org. Chem.  1948,  13:  542 

Carbonyl compounds can also be regenerated from oximes via photochemical and electrochemical methods, but only a few examples have been reported:

9a de Lijser HJP. Fardoun FH. Sawyer JR. Quant M. Org. Lett.  2002,  4:  2325 

9b Haley MF. Yates K. J. Org. Chem.  1987,  52:  1817 

9c Mandic Z. Lopotar N. Electrochem. Commun.  2005,  7:  45 

10 Gawly RE. Org. React.  1988,  35:  1 ; and references cited therein

11 Jiang N. Ragauskas AJ. Tetrahedron Lett.  2010,  51:  4479 

12 Corey EJ. Knapp S. Tetrahedron Lett.  1976,  41:  3667 

13

Typical Procedure for the CuCl ₂ ˙2H ₂ O-Promoted Regeneration of Carbonyl Compounds from Various Oximes
Oxime 1a (1.01 g, 5.12 mmol) was dissolved in MeCN (20 mL), CuCl₂˙2H₂O (1.73 g, 10.15 mmol) and H₂O (5 mL) were added. When the suspension was heated to reflux, the mixture became a bluish clear solution. The resulting reaction solution was then stirred at reflux (75 ˚C) for around 2 h and monitored by TLC (EtOAc-hexane, 1:6). After the reaction was complete, the solvents were removed by vacuum distillation. The residue was partitioned between EtOAc (50 mL) and H₂O (30 mL), the organic and aqueous phases were separated. Organic phase was washed with brine (5 mL) and dried over anhyd MgSO₄. Concentration of the organic solution gave crude product, which was purified by flash chromatography to afford benzophenone (2a, 0.914 g, 5.02 mmol) in 98% yield. To the above-mentioned aqueous phase was added an aq solution of NaOH (11.0 mL, 2 M, 22.00 mmol). After vigorous stirring for 1 h, the bluish solid was collected on a Buchner funnel by suction. After being dried in a warm air at around 50 ˚C for 12 h until the weight of the solid kept constant, Cu(OH)₂˙2H₂O (1.34 g, 10.03 mmol) was recovered in 99% yield.
Spectral analysis showed that compounds 2a-e,i-l,n-s,v obtained from the above hydrolysis are identical with the commercially available authentic samples. Characterization data of compounds 2f-h,m,t,u are as follows:
Compound 2f: ^¹H NMR (400 MHz, CDCl₃): δ = 3.89 (s, 3 H), 7.35 (d, J = 7.9 Hz, 1 H), 7.48-7.57 (m, 4 H), 7.62-7.69 (m, 1 H), 8.18-8.24 (m, 2 H), 9.98 (s, 1 H). MS (EI): m/z (%) = 256 (4) [M⁺], 217 (18), 182 (2), 155 (2), 105 (100), 77 (17). IR (KBr): ν = 3005, 2885, 1735, 1680, 1600, 1505, 1450, 1400, 1255, 1190, 1140, 1120, 1060, 1025, 850, 805, 730, 700 cm^-¹.
Compound 2g: ^¹H NMR (400 MHz, CDCl₃): δ = 1.30 (t, J = 7.1 Hz, 3 H), 4.30 (q, J = 7.1 Hz, 2 H), 4.71 (s, 2 H), 7.02 (d, J = 6.9 Hz, 2 H), 7.85 (d, J = 6.9 Hz, 2 H), 9.90 (s, 1 H). IR (neat): ν = 2980, 2835, 2770, 1755, 1690, 1600, 1510, 1440, 1380, 1310, 1280, 1205, 1160, 1080, 1025, 835, 715, 610 cm^-¹. HRMS (EI): m/z calcd for C₁₁H₁₂O₄ [M⁺]: 208.0736; found: 208.0730.
Compound 2h: ^¹H NMR (400 MHz, CDCl₃): δ = 1.30 (t, J = 7.1 Hz, 3 H), 3.96 (s, 1 H), 4.28 (q, J = 7.1 Hz, 2 H), 4.79 (s, 2 H), 6.84 (d, J = 8.1 Hz, 1 H), 7.41-7.46 (m, 2 H), 9.87 (s, 1 H). IR (KBr): ν = 2980, 2940, 2910, 1750, 1680, 1590, 1510, 1470, 1430, 1395, 1270, 1200, 1140, 1070, 1030, 870, 810, 780, 735, 640 cm^-¹. HRMS (EI): m/z calcd for C₁₂H₁₄O₅ [M⁺]: 238.0841; found: 238.0839.
Compound 2m: ^¹H NMR (400 MHz, CDCl₃): δ = 7.52 (dd, J ₁ = 1.6 Hz, J ₂ = 8.6 Hz, 1 H), 7.67 (d, J = 1.6 Hz, 1 H), 8.29 (d, J = 8.6 Hz, 1 H), 10.07 (s, 1 H), 10.58 (s, 1 H). IR (KBr): ν = 3255, 3085, 2870, 1700, 1620, 1585, 1530, 1480, 1450, 1315, 1255, 1165, 1140, 1080, 985, 850, 760, 705, 540 cm^-¹. MS (EI): m/z (%) = 167 (100) [M⁺], 166 (44), 151 (1), 136 (3), 119 (7), 109 (4), 92 (3), 81 (3), 63 (6).
Compound 2t: ^¹H NMR (400 MHz, CDCl₃): δ = 2.28 (s, 3 H), 3.50-3.69 (m, 2 H), 4.88 (dd, J ₁ = 6.1 Hz, J ₂ = 8.1 Hz, 1 H), 7.03 (d, J = 7.9 Hz, 2 H), 7.13-7.26 (m, 5 H), 7.28-7.35 (m, 2 H), 7.37-7.44 (m, 2 H) 7.48-7.55 (m, 1 H), 7.82-7.89 (m, 2 H). MS (EI): m/z (%) = 332(4) [M⁺], 209 (5), 179 (2), 123 (13), 105 (100), 91 (6), 77 (59). IR (KBr): ν = 3035, 2920, 1685, 1595, 1490, 1450, 1420, 1335, 1220, 980, 810, 745, 700, 685, 550 cm^-¹.
Compound 2u: ^¹H NMR (400 MHz, CDCl₃): δ = 2.05 (s, 3 H), 2.29 (s, 3 H), 2.92-3.08 (m, 2 H), 4.63 (dd, J ₁ = 6.8 Hz, J ₂ = 7.8 Hz, 1 H), 7.03 (d, J = 8.0 Hz, 2 H), 7.18 (d, J = 8.0 Hz, 2 H), 7.19-7.26 (m, 5 H). MS (EI): m/z (%) = 270 (32) [M⁺], 213 (2), 147 (43), 124 (100), 103 (5), 91 (12), 77 (7), 43 (43). IR (neat): ν = 3030, 2940, 1720, 1490, 1455, 1410, 1360, 1150, 1020, 810, 700, 535, 500 cm^-¹.

14 Stutz P. Stadler PA. Org. Synth., Coll. Vol. VI  1988,  109 

15a Horvath IT. Anastas PT. Chem. Rev.  2007,  107:  2167 

15b Horvath IT. Acc. Chem. Res.  2002,  35:  685 

16

When the pH value was kept higher than 9.5, the precipitation of Cu(OH)₂˙2H₂O was complete, which was determined by adding 2 drops of an aq solution of Na₂S into the filtrate. No black CuS appeared.

17

Conversion of Cu(OH) ₂ ˙2H ₂ O into CuCl ₂ ˙2H ₂ O
The above Cu(OH)₂˙2H₂O was first heated at 150 ˚C for around 6 h, and the resulting brown anhyd CuO was then treated with 2.2 molar equivalent of aq HCl at reflux for 2 h. Removal of H₂O under vacuum at 45 ˚C gave blue crystalline CuCl₂˙2H₂O in a nearly quantitative yield.