A Novel Application of (Diacetoxyiodo)benzene for Carbon-Carbon Cleavage of Aryl Diamines and Synthesis of Quinones

Abstract

A novel synthetic utility of hypervalent iodine reagent, (diacetoxyiodo)benzene for diamino aryl carbon-carbon cleavage is described. 1,2-Diamino aryl compounds were successfully converted into the corresponding nitriles, while the developed method was also useful for the preparation of quinones from corresponding 1,4-diamino aryl compounds. The advantages of this protocol are shorter reaction times and mild reaction conditions to obtain moderate to good yields.

Hypervalent iodine reagents have attracted increasing interest during the last decade because of their selective, mild, and environmentally friendly properties as oxidizing agents in organic synthesis. [¹] The relevance of this methodology stems from the fact that all the aforementioned transformations are quite fundamental in nature and can be easily applied to a multitude of synthetic strategies. Investigations from our laboratories have revealed a series of new paradigms for hypervalent iodine mediated reactions under mild conditions. [²]

(Diacetoxyiodo)benzene is a hypervalent iodine reagent which is readily available and frequently used in several oxidative transformations. [³] During the course of our studies, we found that treatment of 1,2-diaminobenzene with (diacetoxyiodo)benzene in acetone resulted into formation of cis,cis-mucononitrile by oxidative cleavage of a carbon-carbon bond. It is interesting to note that, under these reaction conditions, 1,3-diaminobenzene was unaffected while 1,4-diaminobenzene unexpectedly led to formation of benzoquinone.

There are only three previously reported methods available for oxidative cleavage of the carbon-carbon bond of 1,2-diamino aryl compounds, in which compounds such as 1,2-diaminobenzene are treated with molecular oxygen in the presence of CuCl in pyridine and converted into cis,cis-mucononitrile. In another method 1,2-diaminobenzene was oxidized using stoichiometric amount of nickel peroxide or lead tetraacetate. However, all these reactions have several drawbacks such as tedious workup, low yields (less than 50%), and use of toxic reagents. [4] In case of quinone formation from 1,4-diaminobenzene, there are only few methods reported, which include metal oxides in combination with H₂O₂, where the low yields and formation of p-nitro aniline as a major side product is observed. [5]

Thus, in this communication we report the novel application of hypervalent iodine reagent, (diacetoxyiodo)benzene for the oxidative cleavage of the carbon-carbon bond of 1,2-diamino aryl compounds to the corresponding nitriles and preparation of quinones from corresponding 1,4-diamino aryl compounds. There are no prior reports in the literature for oxidative cleavage of aryl diamines or synthesis of quinone using hypervalent iodine reagents.

We selected 1,2-diaminobenzene as a model substrate to explore the suitable reaction conditions with (diacetoxyiodo)benzene in acetone at room temperature (Scheme  [¹] ). In this case, the reaction afforded the corresponding cis,cis-mucononitrile as the major product. [6] We also found that this oxidative transformation takes place in chloroform and dichloromethane, but lower yields were observed. To explore the possibility of other hypervalent iodine reagents for conversion of 1,2-diaminobenzene into cis,cis-mucononitrile, we carried out the reaction with 1,2-diaminobenzene using various hypervalent ­iodine reagents including IBX, KIO₃, and 4,4′-bis-(dichloroiodo)-biphenyl. Unlike the situtation with (diacetoxyiodo)benzene, no formation of cis,cis-mucononitrile was observed even after long reaction times.

In order to explore the reaction scope, a variety of substituted 1,2-diamino aryl compounds was prepared by standard reported procedures and converted into the corresponding nitriles by oxidative carbon-carbon cleavage in moderate to good yields, and the results are summarized in Table  [¹] . [7a]

It was found that electron-rich 1,2-diaminobenzenes were suitable for this transformation, giving the dinitriles in moderate to good yields in short reaction times (Table  [¹] , entries 2-4), while strongly electron-deficient 1,2-diaminobenzenes and heterocyclic diamines did not undergo this transformation (Table  [¹] , entries 8 and 9). It should be noted that, under these reaction conditions, methoxy and ester groups remain unaffected (Table  [¹] , entries 4 and 5). The reaction system is also useful for 1,2-diaminonaphthalene (Table  [¹] , entry 7).

Under the same reaction conditions, 1,4-diaminobenzene reacted with (diacetoxyiodo)benzene in acetone to give benzoquinone (Scheme  [²] ).

Considering this fact, we studied various substituted 1,4-diaminobenzenes in acetone and obtained the corresponding quinones in short reaction times (Table  [¹] ). [7b] The method was also successfully applied to the synthesis of napthaquinone and anthraquinone from the corresponding diamino compounds (Table  [¹] , entries 13-16).

Table 1 Reaction of (Diacetoxyiodo)benzene with Aryl Diamino Compounds^a (continued)

Entry	Substrate	Product	Time (min)	Yield (%)b
1			15	87
2			10	85
3			10	87
4			15	85
5			20	85
6			15	85
7			20	87
8		-	120	n.r.c
9		-	120	n.r.c
10			10	90
11			15	85
12			15	87
13			10	90
14			15	90
15			10	90
16			10	88
a Reaction conditions: substrate (4.6 mmol), (diacetoxyiodo)benzene (2 equiv) in acetone (15 mL), r.t. b Isolated yields after column chromatography. Structures were confirmed by comparison of IR and ¹H NMR spectra with those of authentic materials. [8] c n.r. = no reaction.

In conclusion, we have exploited a novel application of (diacetoxyiodo)benzene for oxidative cleavage of carbon-carbon aryl diamines to nitriles as well as a novel route for the synthesis of quinones in short reaction times. Both these applications are general, practical, economical, and efficient.

Acknowledgment

V.N.T. thanks All India Council for Technical Education (AICTE) for financial support under Research Promotion Scheme (RPS).

References and Notes

• 1a Zhdankin VV. Stang PJ. Chem. Rev.  2002,  102:  2523 
  Search in Google Scholar
• 1b Zhdankin VV. Curr. Org. Synth.  2005,  2:  121 
  Search in Google Scholar
• 1c Wirth T. Angew. Chem. Int. Ed.  2005,  44:  3656 
  Search in Google Scholar
• 2a Telvekar VN. Patel KN. Kundaikar HS. Chaudhari HK. Tetrahedron Lett.  2008,  49:  2213 
  Search in Google Scholar
• 2b Telvekar VN. Rane RM. Tetrahedron Lett.  2007,  48:  6051 
  Search in Google Scholar
• 3a Kotali A. Harris PA. J. Heterocycl. Chem.  1996,  33:  605 
  Search in Google Scholar
• 3b Kotali A. Tetrahedron Lett.  1994,  36:  6753 
  Search in Google Scholar
• 3c Karade NN. Shirodkar SG. Patil MN. Potrekar RA. Karade HN. Tetrahedron Lett.  2003,  44:  6729 
  Search in Google Scholar
• 3d Yusubov MS. Chi K.-W. Park JY. Karimov R. Zhdankin VV. Tetrahedron Lett.  2006,  47:  6305 
  Search in Google Scholar
• 4a Kajimoto T. Takahashi H. J. Org. Chem.  1976,  41:  1389 
  Search in Google Scholar
• 4b Nakagawa K. Onoue H. Tetrahedron Lett.  1965,  20:  1433 
  Search in Google Scholar
• 4c Nakagawa K. Onoue H. J. Chem. Soc., Chem. Commun.  1965,  396 
• 5a Maaiti S. Dinda S. Banerjee S. Mukherjee A. Bhattacharyya R. Eur. J. Inorg. Chem.  2008,  2038 
• 5b Gharah N. Chakroborty S. Alok M. Bhattacharya R. Inorg. Chim. Acta  2009,  362:  1089 
  Search in Google Scholar
• The cis-cis configuration was confirmed by using NMR, melting point and comparing with literature. See:
• 6a Elvidge JA. Ralph PD. J. Chem. Soc., C  1966,  387 
• 6b Campbell CD. Ress CW. J. Chem. Soc., Chem. Commun.  1965,  192 
• 6c Friedmann G. Gati E. Lahav M. Robinovich D. Shakked Z. J. Chem. Soc., Chem. Commun.  1975,  491 
• 7a

  General Procedure for the Cleavage of 1,2-Diamino-benzene (Table 1, Entry 1)
  To a stirred solution of(diacetoxyiodo)benzene (3g, 9.2 mmol) in acetone (15 mL) was added 1,2-diaminobenzene (0.5 g, 4.6 mmol). The reaction mixture was stirred at r.t. until the starting material was completely consumed (TLC). After completion of reaction, the reaction mixture was quenched with H₂O (20 mL) and further diluted with EtOAc (30 mL). The organic layer was separated and washed successively with 10% NaHSO₄ solution (2 × 20 mL), 10% NaHCO₃ (2 × 15 mL), and H₂O (2 × 20 mL). The organic layer was dried over anhyd Na₂SO₄, filtered, and concentrated under reduced pressure to give crude product. Pure mucononitrile was obtained as a colorless solid after silica gel column chromatography (10% EtOAc-hexane).
• 7b

  General Procedure for the Oxidation of 1,4-Diaminobenzene (Table 1, Entry 10)
  To a stirred solution of(diacetoxyiodo)benzene (3g, 9.2 mmol) in acetone (15 mL) was added 1,4-diaminobenzene (0.5 g, 4.6 mmol). The reaction mixture was stirred at r.t. and after completion of reaction (TLC) the reaction mixture was quenched in H₂O and the above workup procedure was followed to obtain benzoquinone.

(2 E ,4 Z )-3-Chlorohexa-2,4-dienedinitrile (Entry 2) Mp 90 ˚C (lit.⁴ mp 89-90 ˚C). IR (KBr): 3050, 2220, 1640, 1111, 784 cm^-¹. ^¹H NMR (300 MHz, CDCl₃): δ = 5.83-5.85 (d, J = 6.0 Hz, 1 H), 5.89 (s, 1 H), 7.32-7.31 (d, J = 6.0 Hz, 2 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 105.6, 105.9, 135.7, 138.1, 147.9, 162.7. ESI-MS: m/z = 137 [M⁺].
(2 E ,4 Z )-3-Methylhexa-2,4-dienedinitrile (Entry 3) Mp 57 ˚C (lit.⁴ mp 56.5-57.5 ˚C). IR (KBr): 3071, 2214, 1640, 1261, 1031, 797 cm^-¹. ^¹H NMR (300 MHz, CDCl₃):
δ = 2.41 (s, 3 H), 5.51 (s, 1 H), 5.68-5.70 (d, J = 5.4 Hz, 1 H), 7.24-7.26 (d, J = 5.4 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 20.6, 102.4,105.2, 115.0, 115.7, 143.5, 153.1. ESI-MS: m/z = 118 [M⁺].
(2 E ,4 Z )-3-Methoxyhexa-2,4-dienedinitrile (Entry 4) Mp 116 ˚C(lit.⁴ mp 116-117 ˚C). IR (KBr): 3061, 2214, 1710, 1627, 1210, 803 cm^-¹. ^¹H NMR (300 MHz, CDCl₃):
δ = 3.86 (s, 3 H), 4.80 (s, 1 H), 5.67-5.71 (d, J = 12.0 Hz, 1 H), 7.05-7.09 (d, J = 12.0 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 29.6, 101.6, 105.9, 113.4, 113.9, 138.1, 148.0. ESI-MS: m/z = 134 [M⁺].
(2 E ,4 Z )-3-Benzoylhexa-2,4-dienedinitrile (Entry 6) Mp 95 ˚C. IR (KBr): 3019, 2214, 1638, 1401, 1319 cm^-¹. ^¹H-NMR (300 MHz, CDCl₃): δ = 5.75-5.78 (d, J = 10.8 Hz, 1 H), 5.82 (s, 1 H), 7.27-7.30 (d, J = 10.8 Hz, 1 H), 7.48-7.79 (m, 5 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 106.3, 108.4, 113.8, 114.0, 129.1, 130.0, 134.5, 135.0, 140.3, 153.1, 191.2. ESI-MS: m/z = 208 [M⁺].
1-Chloroanthracene-9,10-dione (Entry 15) Mp 162 ˚C. IR (KBr): 3082, 1669, 1574, 1318, 1264, 702 cm^-¹. ^¹H NMR (300 MHz, CDCl₃): δ = 7.69-8.30 (m, 7 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 127.54, 128.3, 130.3, 133.1, 134.4, 134.7, 135.3, 135.8, 138.5, 182.6, 183.0. ESI-MS: m/z = 242 [M⁺].
2-Aminoanthracene-9,10-dione (Entry 16) Mp 303-306 ˚C. IR (KBr): 3434, 3331, 1673, 1625, 1588, 1337, 714 cm^-¹. ^¹H NMR (300 MHz, DMSO): δ = 6.68 (s, 2 H), 6.92-8.10 (m, 7 H). ^¹³C NMR (75 MHz, DMSO): δ = 109.8, 118.2, 126.5, 129.7, 133.4, 133.5, 134.4, 135.0, 154.8, 180.2. ESI-MS: m/z = 224 [M + H]⁺.

References and Notes

• 1a Zhdankin VV. Stang PJ. Chem. Rev.  2002,  102:  2523 
  Search in Google Scholar
• 1b Zhdankin VV. Curr. Org. Synth.  2005,  2:  121 
  Search in Google Scholar
• 1c Wirth T. Angew. Chem. Int. Ed.  2005,  44:  3656 
  Search in Google Scholar
• 2a Telvekar VN. Patel KN. Kundaikar HS. Chaudhari HK. Tetrahedron Lett.  2008,  49:  2213 
  Search in Google Scholar
• 2b Telvekar VN. Rane RM. Tetrahedron Lett.  2007,  48:  6051 
  Search in Google Scholar
• 3a Kotali A. Harris PA. J. Heterocycl. Chem.  1996,  33:  605 
  Search in Google Scholar
• 3b Kotali A. Tetrahedron Lett.  1994,  36:  6753 
  Search in Google Scholar
• 3c Karade NN. Shirodkar SG. Patil MN. Potrekar RA. Karade HN. Tetrahedron Lett.  2003,  44:  6729 
  Search in Google Scholar
• 3d Yusubov MS. Chi K.-W. Park JY. Karimov R. Zhdankin VV. Tetrahedron Lett.  2006,  47:  6305 
  Search in Google Scholar
• 4a Kajimoto T. Takahashi H. J. Org. Chem.  1976,  41:  1389 
  Search in Google Scholar
• 4b Nakagawa K. Onoue H. Tetrahedron Lett.  1965,  20:  1433 
  Search in Google Scholar
• 4c Nakagawa K. Onoue H. J. Chem. Soc., Chem. Commun.  1965,  396 
• 5a Maaiti S. Dinda S. Banerjee S. Mukherjee A. Bhattacharyya R. Eur. J. Inorg. Chem.  2008,  2038 
• 5b Gharah N. Chakroborty S. Alok M. Bhattacharya R. Inorg. Chim. Acta  2009,  362:  1089 
  Search in Google Scholar
• The cis-cis configuration was confirmed by using NMR, melting point and comparing with literature. See:
• 6a Elvidge JA. Ralph PD. J. Chem. Soc., C  1966,  387 
• 6b Campbell CD. Ress CW. J. Chem. Soc., Chem. Commun.  1965,  192 
• 6c Friedmann G. Gati E. Lahav M. Robinovich D. Shakked Z. J. Chem. Soc., Chem. Commun.  1975,  491 
• 7a

  General Procedure for the Cleavage of 1,2-Diamino-benzene (Table 1, Entry 1)
  To a stirred solution of(diacetoxyiodo)benzene (3g, 9.2 mmol) in acetone (15 mL) was added 1,2-diaminobenzene (0.5 g, 4.6 mmol). The reaction mixture was stirred at r.t. until the starting material was completely consumed (TLC). After completion of reaction, the reaction mixture was quenched with H₂O (20 mL) and further diluted with EtOAc (30 mL). The organic layer was separated and washed successively with 10% NaHSO₄ solution (2 × 20 mL), 10% NaHCO₃ (2 × 15 mL), and H₂O (2 × 20 mL). The organic layer was dried over anhyd Na₂SO₄, filtered, and concentrated under reduced pressure to give crude product. Pure mucononitrile was obtained as a colorless solid after silica gel column chromatography (10% EtOAc-hexane).
• 7b

  General Procedure for the Oxidation of 1,4-Diaminobenzene (Table 1, Entry 10)
  To a stirred solution of(diacetoxyiodo)benzene (3g, 9.2 mmol) in acetone (15 mL) was added 1,4-diaminobenzene (0.5 g, 4.6 mmol). The reaction mixture was stirred at r.t. and after completion of reaction (TLC) the reaction mixture was quenched in H₂O and the above workup procedure was followed to obtain benzoquinone.

(2 E ,4 Z )-3-Chlorohexa-2,4-dienedinitrile (Entry 2) Mp 90 ˚C (lit.⁴ mp 89-90 ˚C). IR (KBr): 3050, 2220, 1640, 1111, 784 cm^-¹. ^¹H NMR (300 MHz, CDCl₃): δ = 5.83-5.85 (d, J = 6.0 Hz, 1 H), 5.89 (s, 1 H), 7.32-7.31 (d, J = 6.0 Hz, 2 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 105.6, 105.9, 135.7, 138.1, 147.9, 162.7. ESI-MS: m/z = 137 [M⁺].
(2 E ,4 Z )-3-Methylhexa-2,4-dienedinitrile (Entry 3) Mp 57 ˚C (lit.⁴ mp 56.5-57.5 ˚C). IR (KBr): 3071, 2214, 1640, 1261, 1031, 797 cm^-¹. ^¹H NMR (300 MHz, CDCl₃):
δ = 2.41 (s, 3 H), 5.51 (s, 1 H), 5.68-5.70 (d, J = 5.4 Hz, 1 H), 7.24-7.26 (d, J = 5.4 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 20.6, 102.4,105.2, 115.0, 115.7, 143.5, 153.1. ESI-MS: m/z = 118 [M⁺].
(2 E ,4 Z )-3-Methoxyhexa-2,4-dienedinitrile (Entry 4) Mp 116 ˚C(lit.⁴ mp 116-117 ˚C). IR (KBr): 3061, 2214, 1710, 1627, 1210, 803 cm^-¹. ^¹H NMR (300 MHz, CDCl₃):
δ = 3.86 (s, 3 H), 4.80 (s, 1 H), 5.67-5.71 (d, J = 12.0 Hz, 1 H), 7.05-7.09 (d, J = 12.0 Hz, 1 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 29.6, 101.6, 105.9, 113.4, 113.9, 138.1, 148.0. ESI-MS: m/z = 134 [M⁺].
(2 E ,4 Z )-3-Benzoylhexa-2,4-dienedinitrile (Entry 6) Mp 95 ˚C. IR (KBr): 3019, 2214, 1638, 1401, 1319 cm^-¹. ^¹H-NMR (300 MHz, CDCl₃): δ = 5.75-5.78 (d, J = 10.8 Hz, 1 H), 5.82 (s, 1 H), 7.27-7.30 (d, J = 10.8 Hz, 1 H), 7.48-7.79 (m, 5 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 106.3, 108.4, 113.8, 114.0, 129.1, 130.0, 134.5, 135.0, 140.3, 153.1, 191.2. ESI-MS: m/z = 208 [M⁺].
1-Chloroanthracene-9,10-dione (Entry 15) Mp 162 ˚C. IR (KBr): 3082, 1669, 1574, 1318, 1264, 702 cm^-¹. ^¹H NMR (300 MHz, CDCl₃): δ = 7.69-8.30 (m, 7 H). ^¹³C NMR (75 MHz, CDCl₃): δ = 127.54, 128.3, 130.3, 133.1, 134.4, 134.7, 135.3, 135.8, 138.5, 182.6, 183.0. ESI-MS: m/z = 242 [M⁺].
2-Aminoanthracene-9,10-dione (Entry 16) Mp 303-306 ˚C. IR (KBr): 3434, 3331, 1673, 1625, 1588, 1337, 714 cm^-¹. ^¹H NMR (300 MHz, DMSO): δ = 6.68 (s, 2 H), 6.92-8.10 (m, 7 H). ^¹³C NMR (75 MHz, DMSO): δ = 109.8, 118.2, 126.5, 129.7, 133.4, 133.5, 134.4, 135.0, 154.8, 180.2. ESI-MS: m/z = 224 [M + H]⁺.