Abstract
A very simple and efficient procedure is reported for the synthesis of 1,3-diarylimidazolinium chlorides by cyclization of N ,N ′-diarylethylenediamines dihydrochlorides with triethyl orthoformate under microwave irradiation.
Key words
amines - cyclizations - heterocycles - imidazolinium salts - ligands
References and Notes
1a Herrmann WA.
Köcher C.
Angew. Chem., Int. Ed. Engl.
1997,
36:
2162
1b Arduengo AJ.
Acc. Chem. Res.
1999,
32:
913
2 Bourissou D.
Guerret O.
Gabbaï FP.
Bertrand G.
Chem. Rev.
2000,
100:
39
3a Herrmann WA.
Kohl FJ.
Schwartz J. In
Synthetic Methods of Organometallic and Inorganic Chemistry
Vol. 9:
Herrmann WA.
Thieme;
Stuttgart:
2000.
p.84
3b Herrmann WA.
Weskamp T.
Böhm VPW.
Adv. Organomet. Chem.
2001,
48:
1
3c Herrmann WA.
Angew. Chem. Int. Ed.
2002,
41:
1290
4a Jafarpour L.
Nolan SP.
Adv. Organomet. Chem.
2001,
46:
181
4b Scott NM.
Nolan SP.
Eur. J. Inorg. Chem.
2005,
1815
4c Dragutan I.
Dragutan V.
Demonceau A.
Platinum Met. Rev.
2005,
49:
123
4d Dragutan I.
Dragutan V.
Demonceau A.
Platinum Met. Rev.
2005,
49:
183
5a Nair V.
Bindu S.
Sreekumar V.
Angew. Chem. Int. Ed.
2004,
43:
5130
5b Enders D.
Balensiefer T.
Acc. Chem. Res.
2004,
37:
534
5c César V.
Bellemin-Laponnaz S.
Gade LH.
Chem. Soc. Rev.
2004,
33:
619
6a Arduengo AJ.
Harlow RL.
Kline M.
J. Am. Chem. Soc.
1991,
113:
361
6b Arduengo AJ.
Rasika Dias HV.
Harlow RL.
Kline M.
J. Am. Chem. Soc.
1992,
114:
5530
6c Arduengo AJ.
Goerlich JR.
Marshall WJ.
J. Am. Chem. Soc.
1995,
117:
11027
7a Delaude L.
Szypa M.
Demonceau A.
Noels AF.
Adv. Synth. Catal.
2002,
344:
749
7b Grasa GA.
Viciu MS.
Huang J.
Zhang C.
Trudell ML.
Nolan SP.
Organometallics
2002,
21:
2866
7c Nyce GW.
Glauser T.
Connor EF.
Möck A.
Waymouth RM.
Hedrick JL.
J. Am. Chem. Soc.
2003,
125:
3046
8a Arduengo AJ.
Krafczyk R.
Schmutzler R.
Craig HA.
Goerlich JR.
Marshall WJ.
Unverzagt M.
Tetrahedron
1999,
55:
14523
8b Van Veldhuizen JJ.
Gillingham DG.
Garber SB.
Kataoka O.
Hoveyda AH.
J. Am. Chem. Soc.
2003,
125:
12502
8c Ma Y.
Song C.
Jiang W.
Wu Q.
Wang Y.
Liu X.
Andrus MB.
Org. Lett.
2003,
5:
3317
8d Xu G.
Gilbertson SR.
Org. Lett.
2005,
7:
4605
9a Saba S.
Brescia A.-M.
Kaloustian MK.
Tetrahedron Lett.
1991,
32:
5031
9b Garber SB.
Kingsbury JS.
Gray BL.
Hoveyda AH.
J. Am. Chem. Soc.
2000,
122:
8168
9c Grasa GA.
Viciu MS.
Huang J.
Nolan SP.
J. Org. Chem.
2001,
66:
7729
9d Seiders TJ.
Ward DW.
Grubbs RH.
Org. Lett.
2001,
3:
3225
9e Kingsbury JS.
Hoveyda AH.
J. Am. Chem. Soc.
2005,
127:
4510
10a Microwaves in Organic Synthesis
Loupy A.
Wiley-VCH;
Weinheim:
2002.
10b Kappe CO.
Angew. Chem. Int. Ed.
2004,
43:
6250
10c Kappe CO.
Stadler A.
Microwaves in Organic and Medicinal Chemistry, In Methods and Principles in Medicinal Chemistry
Vol. 25:
Mannhold R.
Kubinyl H.
Folkers G.
Wiley-VCH;
Weinheim:
2005.
11a Caddick S.
Tetrahedron
1995,
51:
10403
11b Lidström P.
Tierny J.
Wathey B.
Westman J.
Tetrahedron
2001,
57:
9225
11c Hayes BL.
Aldrichimica Acta
2004,
37:
66
12 Xu Y.
Guo Q.-X.
Heterocycles
2004,
63:
903
13a Usyatinsky AY.
Khmelnitsky YL.
Tetrahedron Lett.
2000,
41:
5031
13b Balalaie S.
Arabanian A.
Green Chem.
2000,
2:
274
13c Wolkenberg SE.
Winoski DD.
Leister WH.
Wang Y.
Zhao Z.
Lindsley CW.
Org. Lett.
2004,
6:
1453
14 Starikova OV.
Dolgushin GV.
Larina LI.
Komarova TN.
Lopyrev VA.
ARKIVOC
2003,
(xiii):
119
15 Hayes BL.
Microwave Synthesis: Chemistry at the Speed of Light
CEM Publishing;
Matthews, NC:
2002.
p.29-74
16
General Procedure for the Microwave-Assisted Synthesis of 1,3-Diarylimidazolinium Chlorides.
A 10-mL glass vial equipped with a stirring bar was charged with a N ,N ′-diarylethylenediamine dihydrochloride (1 mmol) and triethyl orthoformate (1-2 mL). The vial was capped and irradiated 5 min at 145 °C (monitored by IR sensor) in a CEM Discover instrument with a 50-W microwave power. No ramp and no simultaneous cooling were applied. After rapid air cooling by the unit, the reaction mixture was diluted with Et2 O (3 mL) and filtered under vacuum. The precipitate was rinsed with a few milliliters of Et2 O and dried under vacuum to afford pure 1,3-diaryl-imidazolinium chloride.
17
1 H NMR (400 MHz, DMSO-d
6 ): δ = 2.35 (s, 6 H, para -CH3 ), 4.55 ppm (s, 4 H, CH2 ), 7.35 (d, J = 4.0 Hz, 2 H, CH
ortho
), 7.60 (d, J = 4.0 Hz, 2 H, CH
meta
), 10.13 (s, 1 H, im-CH2 ). 13 C NMR (100 MHz, DMSO-d
6 ): δ = 20.5 (para -CH3 ), 48.3 (CH2 ), 118.4 (CH
ortho
), 130.0 (CH
meta
), 133.8 (C
para
), 136.4 (C
ipso
), 151.1 (im-CH2 ).
18 Maj, A.; Delaude, L.; Demonceau, A.; Noels, A. F. manuscript in preparation .
19 Scholl M.
Ding S.
Lee CW.
Grubbs RH.
Org. Lett.
1999,
1:
953
20
Scaled-up Preparation of 1,3-Dimesitylimidazolinium Chloride.
N ,N ′-dimesitylethylenediamine dihydrochloride (7.39 g, 20 mmol) and triethyl orthoformate (15 mL). The vial was capped and irradiated 5 min at 145 °C (monitored by IR sensor) in a Biotage Emrys Optimizer instrument with a 75-W microwave power. No ramp was applied. After rapid cooling in an ice bath, the reaction mixture was diluted with Et2 O (20 mL) and filtered under vacuum. The precipitate was rinsed with Et2 O (2 × 10 mL) and dried under vacuum to afford pure 1,3-dimesitylimidazolinium chloride (6.57 g, 97% yield).
