Synthetic Communications Solid State Oxidation of ...

This article was downloaded by: On: 28 January 2011 Access details: Access Details: Free Access Publisher Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 3741 Mortimer Street, London W1T 3JH, UK

Synthetic Communications

Publication details, including instructions for authors and subscription information: http://www.informaworld.com/smpp/title~content=t713597304

Solid State Oxidation of Thiols to Disulfides Using Ammonium Persulfate

Rajender S. Varmaab; Harshadas M. Meshrambc; Rajender Dahiyaad a Department of Chemistry and Texas Research Institute for Environmental Studies (TRIES), Sam Houston State University, Huntsville, Texas, U.S.A. b Houston Advanced Research Center (HARC), 4800 Research Forest Drive, The Woodlands, Texas, U.S.A. c Organic Chemistry Division, Indian Institute of Chemical Technology, Hyderabad, India d M.L.N. College, Yamuna Nagar, Haryana, India

To cite this Article Varma, Rajender S. , Meshram, Harshadas M. and Dahiya, Rajender(2000) 'Solid State Oxidation of

Thiols to Disulfides Using Ammonium Persulfate', Synthetic Communications, 30: 7, 1249 — 1255 To link to this Article: DOI: 10.1080/00397910008087146 URL: http://dx.doi.org/10.1080/00397910008087146

PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

SYNTHETIC COMMUNICATIONS, 30(7), 1249-1255 (2000)

SOLID STATE OXIDATION OF THIOLS TO DISULFIDES USING AMMONIUM PERSULFATE Rajender S. Varma,*1*2 Harshadas M. Meshramzt and Rajender Dahiyal*

Downloaded At: 19:05 28 January 2011

IDepartment of Chemistry and Texas Research Institute for Environmental Studies (TRIES), Sam Houston State University. Huntsville, Texas 77341-2117, U.S.A. ZHoustonAdvanccd Research Center (HARC), 4800 Research Forest Drive, The Woodlands, Texas 7738 1, U.S.A.

ABSTRACT: A solid state method for the oxidation of thiols is described that uses benign oxidant, ammonium persulfate.

The transformation of thiols to disulfides is important both, synthetically as well as biologically.1-12 This conversion has been accomplished using a variety of reagents such as molecular oxygen,z metal ions,3 metal oxides,3a DMSO,4 nitric oxide,5 halogens,6 sodium perborate,7 electrochemical oxidation.8 clayfen,g borohydride exchange resin (BER)-transition metal salts system.10 morpholineiodine complex1 I and horseradish peroxidase or mushroom tyrosinase. 12 Most of

*To whom correspondence should be addressed. tpresent address: Organic Chemistry Division, Indian Institute of Chemical Technology, Hyderabad, 500 007. India. $On leave of absence from M.L.N. College, Yamuna Nagar- 135001, Haryana, India. 1249 Copyright Q ZOO0 by Marcel Dekker, Inc.

w ww .dekker.com

VARMA, MESHRAM, AND DAHIYA

1250

the reagents involve metal ions and solvents in protocols that lack the general applicability to thiol substrates bearing alkyl, aryl and heterocyclic moieties and are not eco-friendly. There is increasing emphasis on technological developments that deploy environmentally friendly reagents or proceed in the absence of solventsl3 or utilize mechano-chemical techniques.I4 Consequently, there is scope for the development of general oxidation protocol that ideally proceed in the absence

of solvent and preferably without a metal ion thereby reducing the waste generation. s we report Because of our interest in development of solvent-free r e a c t i ~ n s , ~herein a facile oxidation of thiols to disulfides in solid state using a benign oxidant, Downloaded At: 19:05 28 January 2011

ammonium persulfate. Ammonium persulfate is relatively inexpensive, stable and easily handled oxidizing agent in comparison to most oxidants usually employed for this transformation. The most common application of this reagent in the chemical industry is for bleaching.16 It has also been used for the oxidation of alkenesl7 and substituted aromatics,l8 for c y c l i ~ a t i o n 'and ~ for deoximation of steroidal oximes,20 but its general applicability in organic synthesis has largely been unexplored.

A variety of thiols, aliphatic (cyclic and acyclic), aromatic and heterocyclic, are converted into symmetrical disulfides upon simple admixing with solid ammonium persulfate. The process in its entirety involves grinding the thiols with ammonium persulfate using a pestle and motar in an ambient air environment at room temperature. The reaction mixture that is sticky to begin with becomes granular within 10 min which indicates the completion of the reaction as revealed by

TLC examination. In most cases investigated, the optimum mole ratio between the substrate and the oxidant is found to be 1 :1.1 which delivers pure disulfides in good yields. On the other hand, the fused ring heterocycles (entry 3-5) and long chain aliphatic thiols (entry 9,lO) under these conditions afforded only traces of

AMMONIUM PERSULFATE

1251

disulfides even after 24 h. These reactions could be completed, however, by increasing the substrate-reagent ratio and 11ie reaction time (table). Interestingly. thiophenol gives disulfide in very poor yield (5-10%) even with excess of the oxidant, presumably due to its acidic nature.21 However, increasing the basicity21

of the reaction with ethylenediamine. the rate of reaction and the yield increases dramatically.

(NH4)2S208


R-sH

Mixing

*

R-S-S-R

Table: Oxidation of thiols to disulfides using ammonium persulfate Entry Thiols Mole ratios Method Time Yieldab ThiOY min/(h) (NH4)2S208 1:l.l

A

10

8322

2

1:l.l

A

15

9322

3

1: 10

A

40

8423

4

1:lO

A

35

871 1

5

1:10

A

35

90'

6

1:l.l

B

10

7924

7

1:l.l

B

9

8024

8

1:l.l

A

20

891°

9

1:lO

A

(23)

9625

10

1:lO

A

(21)

9526

1:l.l

B

20

7110

1 SH

11

HOCH~CHZSH

alsolaled and unoptimized yields. bAll products are characterized by GC-MS and comparison of the m.p. with that of the authentic samples.

'H NMR. 13C NMR,


1252

Experimental Section

General: TLC was performed on silica gel plates obtained from Analtech, Inc. using hexane:ethyl acetate (4: 1, v/v) as the solvent system. Melting points were determined on a Mel-Temp I1 hot stage apparatus using Fluke 51 WJ digital thermometer and are uncorrected. NMR spectra were recorded in CDCl3 on a Jeol Eclipse+ 300 (300.53 MHz for 1H NMR and 75.57 MHz for 13C NMR) spectrometer using TMS as an internal standard. Mass spectra were recorded on a Hewlett PackardB 5972 mass spectrometer (70 eV) using a G U M S coupling. The Downloaded At: 19:05 28 January 2011

products were characterized by comparison of their physical and spectral data with those reported in the literature. General Procedure-A: Thiol (0.01 mol) and ammonium persulfate (0.01 1 rnol) were mixed thoroughly using pestle and mortar. The reaction mixture was placed in air at room temperature with further occasional mixing. On completion of the reaction, monitored on TLC, the product was extracted into dichloromethane (4x30 mL). The removal of solvent under reduced pressure afforded pure disulfide.

General Procedure-B: Thiol (0.01 mol) and ethylenediamine (0.005 mol) were mixed thoroughly. Then ammonium persulfate (0.01 1 mol) was added and mixed using a pestle and mortar. After some time the reaction becomes granular. After the completion of the reaction (TLC), the product was extracted with dichloromethane. On removal of solvent under reduced pressure, the crude product was passed through a small bed of silica with hexane or hexane-dichloromethane (4: 1) to obtain a pure product. In conclusion, the use of ammonium persulfate under solvent-free conditions provides a remarkably simple, mild and general oxidative protocol for the oxidation of thiols to disulfides. The method is applicable to a wide variety of aromatic, aliphatic and heterocyclic systems.

AMMONIUM PERSULFATE

Acknowledgment:

1253

We are grateful to the Houston Environmental Initiative

Program at Houston Advanced Research Center (HARC) and the Retina Research Foundation for the financial support.

References a n d Notes 1. Capozzi, G. and Modena, G. The Chemistry of the Thiol Group. In “The Chemistry of Functional Groups,” Patai, S., Ed., John Wiley & Sons, New York 1974, Part I , pp 758-839.


2.

Liu, K.-T. and Tong, Y.C. Synthesis 1978, 669.

3. (a) Wallace, T.J. J. Org. Chem. 1966,31, 3071. (b) Sato, T.; Otera, J. and Nozaki, H. Tetrahedron Lett. 1990.31. 3591.

4. (a) Yiannions, C.N. and Karabinos, J.V. J. Org. Chem. 1963, 28, 3246. (b) Wallace, T.J. J. Am. Chem. SOC. 1964, 86, 2108. 5.

Pryor, W.A.; Church, D.F.; Govindan, C.K. and Crank, G. J. Org. Chern. 1982, 47, 156.

6. (a) Schaeffer, J.R.; Goodhue, C.D.; Risle, H.A. and Stevens, R.E. J . Org. Chem. 1967, 32, 392. (b) Drabowicz, J. and Mikolajczyk, M. Synrhesis 1980, 32.

7 . McKillop, A. and Koyuncu, D. Tetrahedron Lett. 1990,31, 5007. 8.

(a) Leite, S.L.S.; Pardini, V.L. and Viertler, H. Synth. Commun. 1990,20, 393. (b) Niyazymbetov, M.E.; Konyushkin, L.D.; Niyazymbetova, Z.I.; Litvinov, V.P. and Petrosyan, V.A. Synth. Commun. 1993,23, 1659.

9

Meshram, H.M. Org. Prep. Proc. lnt. 1993,25, 232.

10. Choi, J. and Yoon, N.M. J. Org. Chem. 1995,60, 3266. 11. Ramadas, K. and Srinivasan, N. Synth. Commun. 1996,26, 4179. 12. Sridhar, M.; Kumara, S. and Bhalerao, U.T. Synth.Commun. 1998.28, 1499.


1254

13. Toda, F. Synlett 1993, 303. 14. Barman, S. Chem. & Eng. News 1993, October 11, p 5. 15. For cleavage-deprotection reactions see: (a) Varrna, R.S. and Saini, R.K.

Tetrahedron Lett. 1997,38, 2623. (b) Varrna, R.S. and Meshram, H.M. Tetrahedron Lett. 1997,38, 5427. (c) Varma, R.S. and Meshrarn, H.M. Tetrahedron Lett. 1997,38, 7973. (d) Varma, R.S.; Dahiya, R. and Saini,

P.K. Tetrahedron Lett. 1997,38, 88 19. For condensation-cyclization reactions see: (e) Varrna, R.S.; Dahiya, R. and Kurnar, S. Tetrahedron Lett.


1997,38, 2039.

(0 Varma, R.S. arld Dahiya, R. Synlett 1997, 1245. (g)

Varma, R.S.; Dahiya, R. and Kurnar, S. Tetrahedron Lett. 1997.38, 5131. (h) Varma, R.S. and Saini, R.K.Synlett 1997, 857. For oxidation reactions see: (i) Varma, R.S. and Dahiya, R. Tetrahedron Lett. 1997,38, 2043. (i) Varma, R.S.; Saini, R.K. and Meshrarn, H.M. Tetrahedron Lett. 1997.38, 6525. (k) Varrna, R.S.; Dahiya, R. and Saini, R.K. Tetrahedron Lett. 1997,

38, 7029. (I) Varrna, R.S.; Saini, R.K. and Dahiya, R. Tetrahedron Lett. 1997.38, 7823. (rn) Varma, R.S.; Dahiya, R. and Saini, R.K. Tetrahedron

Lett. 1997.38, 7029. (n) Varma, R.S. and Dahiya, R. Tetrahedron Lett. 1998.39, 1307. (0)Varrna, R.S.: Dahiya, R. and Kumar, D. Molecules

Online 1998,2, 82. (p) Varma, R.S. and Saini, R.K. Tetrahedron Lett. 1998,39, 1481. (9) Varma, R.S.; Saini, R.K. and Dahiya, R. J. Chem.

Res. (S)1998, 120. (r) Varma, R.S. and Naicker, K.P.Molecules Online 1998,2, 94. For reduction reactions see: (s) Varma, R.S. and Saini, R.K.

Tetrahedron Lett. 1997,38,4337. (t) Varrna, R.S. and Dahiya, R. Tetrahedron 1998,54. 6293. 16. Kazunobu, N. and Kanetsugu, T. Japan parent Appl. 71 96,636; Chem.

Abstr.: 1974,80, 16373111. 17. Fristad, W.E.and Peterson, J.R. Tetrahedron Lett. 1983,24,4547.

AMMONIUM PERSULFATE

1255

18. Angelo, C. and Ombretta, P. Can. J. Chem. 1980, 58, 21 17. 19. Tryupina, V.M.; Almaev, R.Kh.; Bikkulov, A.Z.; Kalinina, V.M. and Baiguzina, G.A. USSR SU 1,198,073; C h p . Abstr.: 1986, 105, 152926f.

20

Brooks, S.G.; Evans, R.M.; Green, G.F.H.; Hunt, J.S.; Long, A.G.;

Mooney, B. and Wyman. L.J. J. Chem. SOC. 1958,4614. 21. Oae, S. "The Sulfur Chemistry: Structure and Mechanism"; CRC Press, London, 1991, pp 204.

22. Danehy, J.P.; Elia. V.J. and Lavelle, C.J. J. Org. Chem. 1971,36, 1003. 23. Arbzov, B.A.; Zoroastrova, V.M. lzvest. Acad. Nauk S.S.S.R, Otdel. Downloaded At: 19:05 28 January 2011

Khim. Nauk 1959, 1037; Chem Abstr.: 1960,54, 14981.

24. Weast, R.C. and Astrl, M.J. "CRC Handbook Data on Organic Compounds"; CRC Press, Inc., Boca Raton, FL, 1988.

25. El-Hewehi, Z. and Runge, F. Martin-Luther-Univ. 1959.8, 1013; Chenz. Abstr.: 1961.55, 114321. 26. Reid, E.E. Organic Chemistry ofBivalent Sulfur Compounds, Vol 3, pp 395.

(Received in the USA 09 August 1999)