An Improved Procedure for the Photoacylation of 1,4-Naphthoquinone with Aliphatic Aldehydes

Abstract

Irradiation of 1,4-naphthoquinone at 300±25 nm in benzene and in the presence of aliphatic aldehydes readily yields acylated hydroquinones in good to high yields. The developed protocol represents a significant improvement over the original procedure using medium-pressure mercury lamps. Subsequent oxidation gives the corresponding acylated quinones.

Key words

acylations - photochemistry - quinones - aldehydes

References and Notes

• 2a Thomson RH. Naturally Occurring Quinones IV   Blackie; Glasgow: 1996. 
• 2b Thomson RH. Naturally Occurring Quinones III, Recent Advances   Chapman & Hall; London: 1987. 
• 2c Bérdy J. Aszalos A. Bostian N. McNitt KL. CRC Handbook of Antibiotic Compounds. Quinone and Similar Antibiotics   Vol. 3:  CRC; Boca Raton: 1980. 
• 2d The Chemistry of the Quinonoid Compounds   Patai S. John Wiley & Sons; New York: 1974. 
• 3a Hase J. Nishimura T. J. Pharm. Soc. Jpn.  1955,  75:  203 
• 3b Hase J. Nishimura T. J. Pharm. Soc. Jpn.  1955,  75:  207 
• 4a Suganuma H. J. Synth. Org. Chem. Jpn.  2001,  59:  23 
• 4b Koura Y. Kinoshita S. Takasuka K. Koura S. Osaki N. Matsumoto S. Miyoshi H. J. Pesticide Sci.  1998,  23:  18 
• 5a Papapgeorgiou VP. Assimopoulou AN. Couladouros EA. Hepworth D. Nicolaou KC. Angew. Chem. Int. Ed.  1999,  38:  270 ; Angew. Chem. 1999, 111, 280
• 5b Couladouros EA. Strongilos AT. Eur. J. Org. Chem.  2002,  3341 
• 6a For pyrano-[2,3-c]-naphthoquinone antibiotics, see: Brimble MA. Nairn MR. Prabaharan H. Tetrahedron  2000,  56:  1937 
• 6b For 1,4-benzodiazepines, see: Kraus GA. Maeda H. Tetrahedron Lett.  1994,  35:  9189 
• 6c For lapachones, see: Maruyama K. Naruta Y. Chem. Lett.  1977,  847 
• 7 Kurosawa E. Quinones I. Bull. Chem. Soc. Jpn.  1961,  34:  300 
• 8 Yadav JS. Subba Reddy BV. Swamy T. Raghavender Rao K. Tetrahedron Lett.  2004,  45:  6037 
• 9 Rathwell K. Brimble MA. Synthesis  2007,  643 
• 10 Boyer JL. Krum JE. Myers MC. Fazal AN. Wigal CT. J. Org. Chem.  2000,  65:  4712 
• 11 Sharma PK. Khanna RN. Monatsh. Chem.  1985,  116:  353 
• 12a For a recent review on the photoacylation of quinones, see: Oelgemöller M. Mattay J. In CRC Handbook of Organic Photochemistry and Photobiology   2nd ed.:  Horspool WM. Lenci F. CRC; Boca Raton: 2004.  Chap. 88. p.1-45  
• 12b For a general review on the photochemistry of quinones, see: Maruyama K. Osuka A. In The Chemistry of Quinonoid Compounds   Vol. 2:  Patai S. Rappoport Z. John Wiley & Sons; New York: 1988.  Chap. 13. p.759-878  
• 13a Waske PA. Mattay J. Oelgemöller M. Tetrahedron Lett.  2006,  47:  1329 
• 13b Oelgemöller M. Schiel C. Fröhlich R. Mattay J. Eur. J. Org. Chem.  2002,  2465 
• 13c Schiel C. Oelgemöller M. Mattay J. Synthesis  2001,  1275 
• 13d Schiel C. Oelgemöller M. Ortner J. Mattay J. Green Chem.  2001,  3:  224 
• 13e Schiel C. Oelgemöller M. Mattay J. J. Inf. Rec.  1998,  24:  257 
• 14a Kraus GA. Kirihara M. J. Org. Chem.  1992,  57:  3256 
• 14b Kraus GA. Liu P. Tetrahedron Lett.  1994,  35:  7723 
• 15 Maruyama K. Miyagi Y. Bull. Chem. Soc. Jpn.  1974,  47:  1303 
• 17 Singh I. Ogata RT. Moore RE. Chang CW. Scheuer PJ. Tetrahedron  1968,  24:  6053 
• 20 Spruit CJP. Recl. Trav. Chim. Pays-Bas  1947,  66:  655 
• 22 Helferich B. Klein W. Justus Liebigs Ann. Chem.  1926,  450:  219 

1

New address from 2009: School of Pharmacy and Molecular Sciences, James Cook University, Townsville, Queensland 4811, Australia. E-mail: [e-mail]

16

Lamp data provided by Luzchem Research Inc., 5509 Canotek Road, Unit 12, Ottawa, Ontario K1J 9J9, Canada (http://www.luzchem.com).

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General Procedure for Irradiation
In a typical photochemical experiment, a solution of naphthoquinone (1 mmol) and aldehydes (5 mmol) in anhyd benzene (50 mL) was degassed with argon and irradiated in a Pyrex vessel for 22-30 h using a Rayonet Photochemical reactor (RPR-200; Southern New England Ultraviolet Company) equipped with RPR-3000 Å lamps (λ_max = 300±25 nm). The large-scale reaction was performed with 20 mmol of 1 and 140 mmol of 2b in 100 mL of benzene instead. The reaction was continued until TLC analysis (silica gel, EtOAc-n-hexane mixtures) indicated complete consumption of the quinone. The solution was evaporated to a smaller volume of about 10 mL. On standing at 0 ˚C (fridge) the photoproducts readily precipitated (several crops). Filtration, washing with cold benzene, followed by cold n-hexane, and drying in vacuum gave the desired products 3.
Selected Physical and Spectral Data for 1-(1,4-Dihydroxynaphthalen-2-yl)-dodecan-1-one (3l) Yellow solid, mp 100-102 ˚C. ^¹H NMR (400 MHz, CDCl₃): δ = 0.88 (t, 3 H, J = 6.8 Hz, CH₃), 1.21-1.46 (br m, 16 H, 8 × CH₂), 1.78 (dq, 2 H, J = 7.5, 7.2 Hz, COCH₂CH ₂), 2.97 (t, 2 H, J = 7.5 Hz, COCH ₂), 4.96 (br s, 1 H, 4-OH), 7.03 (s, 1 H, ArH), 7.58 (ddd, 1 H, J = 8.4, 7.2, 1.4 Hz, ArH), 7.68 (ddd, 1 H, J = 8.4, 7.2, 1.4 Hz, ArH), 8.10 (dd, 1 H, J = 8.4, 1.2 Hz, ArH), 8.46 (dd, 1 H, J = 8.4, 1.2 Hz, ArH), 13.79 (s, 1 H, 1-OH). ^¹³C NMR (100 MHz, CDCl₃): δ = 14.3, 22.8, 24.7, 29.4, 29.5, 29.6, 29.7, 29.8, 29.9, 32.5, 39.0, 105.6, 111.8, 121.6, 124.8, 126.3, 126.7, 129.4, 129.8, 143.0, 157.6, 206.2. MS (EI): m/z = 342 [M⁺], 324, 215, 202, 197, 187, 173, 131, 77, 55, 43. IR (KBr): ν = 3340, 2950-2850, 1640, 1590, 1460, 1400, 1290, 1190, 1140, 1080, 1040, 880, 820, 770 cm^-¹. HRMS (EI⁺): m/z calcd for 342.21949; found: 342.21883.

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Crystal Data for 3b
Brownish-yellow prisms (from benzene), mp 164-166 ˚C, C₁₃H₁₂O₃, FW = 216.23 g/mol, monoclinic, space group P21/c; a = 11.1180 (3), b = 8.8795 (3), c = 21.2353 (8) Å; β = 96.176 (1)˚; V = 2084.23 (12) Å^³; Z = 8; d _calc  = 1.378
g/cm^³; R = 0.0714, R _W = 0.110 for 3198 reflections having F > 2σ(F).
Crystal Data for 3g
Brownish-yellow prisms (from benzene), mp 139-142 ˚C, C₁₇H₂₀O₃, FW = 272.33 g/mol, orthorhombic, space group Pccn; a = 24.9503 (11), b = 12.8054 (4), c = 8.9576 (3) Å; V = 2861.94 (18) Å^³; Z = 8; d _calc  = 1.378 g/cm^³; R = 0.0721, R _W = 0.1057 for 2099 reflections having F > 2σ(F).
Further crystallographic data have been deposited at the Cambridge Crystallographic Data Centre (CCDC-692479 and CCDC-692480). These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif.

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General Procedure for Oxidation
Acylated photoproduct (1.5 mmol) was dissolved in anhyd Et₂O (50 mL). Anhyd Na₂SO₄ (3.0 g, 21 mmol) was added, followed by freshly prepared Ag₂O (575 mg, 2.5 mmol) in small portions.^²² The suspension was stirred overnight in the dark at r.t. (TLC control: silica gel, EtOAc-n-hexane mixtures), filtered over a pad of Celite, and concentrated to dryness. The crude product was recrystallized from cold Et₂O. Filtration and drying in vacuum gave the desired acylated naphthoquinones 4.
Selected Physical and Spectral Data for 2-Undecanoyl-1,4-naphthoquinone (4l)
Yellow solid, mp 62-64 ˚C. ^¹H NMR (400 MHz, CDCl₃): δ = 0.88 (t, 3 H, J = 6.8 Hz, CH₃), 1.20-1.40 (br m, 16 H, 8 × CH₂), 1.68 (dq, 2 H, J = 7.2 Hz, COCH₂CH ₂), 2.93 (t, 2 H, J = 7.2 Hz, COCH ₂), 7.08 (s, 1 H, H_quin.), 7.81 (m, 2 H, ArH), 8.10 (m, 2 H, ArH). ^¹³C NMR (100 MHz, CDCl₃): δ = 14.3, 22.8, 23.7, 29.2, 29.4, 29.5, 29.6, 29.7, 29.8, 32.1, 43.7, 126.5, 127.0, 131.8, 131.9, 134.5, 134.7, 136.7, 146.2, 183.5, 185.2, 201.2. IR (KBr): ν = 2951, 2852, 1696, 1672, 1589, 1495, 1452, 1296, 1251, 1224, 1050, 878, 824, 714 cm^-¹. HRMS (EI⁺): m/z calcd for 340.20385; found: 340.20326.