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Synlett 2009(10): 1575-1578  
DOI: 10.1055/s-0029-1217337
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Reaction between N-Isocyaniminotriphenylphosphorane, Aldehydes, and Carboxylic Acids: A One-Pot and Three-Component Synthesis of 2-Aryl-5-hydroxyalkyl-1,3,4-oxadiazoles

Mehdi Adib*a, Mahdi Riazati Kesheha, Samira Ansaria, Hamid Reza Bijanzadehb
a School of Chemistry, University College of Science, University of Tehran, PO Box 14155-6455, Tehran, Iran
Fax: +98(21)66495291; e-Mail: madib@khayam.ut.ac.ir;
b Department of Chemistry, Tarbiat Modarres University, PO Box 14115-175, Tehran, Iran
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Received 22 January 2009
Publikationsdatum:
02. Juni 2009 (online)

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Abstract

A one-pot and three-component synthesis of 2-aryl-5-hydroxyalkyl-1,3,4-oxadiazoles is described. N-Isocyaniminotriphenylphosphorane, an aldehyde, and a carboxylic acid undergo a 1:1:1 addition reaction under mild conditions to afford the title compounds in good yields.

Key words

2-aryl-5-hydroxyalkyl-1,3,4-oxadiazoles - N-isocyaniminotriphenylphosphorane - aldehydes - carboxylic acids - three-component reactions - cyclizations - heterocycles

18

Procedure for the Preparation of 2-(4-Bromophenyl)-5-(1-hydroxyethyl)-1,3,4-oxadiazole (5a)
A mixture of N-isocyaniminotriphenylphosphorane (0.302 g, 1 mmol), acetaldehyde (0.176 g, 4 mmol), 4-bromobenz-oic acid (0.201 g, 1 mmol) in CH2Cl2 (4 mL) was stirred at ambient temperature for 24 h. Then, the solvent was removed, and the residue was purified by column chromatography using n-hexane-EtOAc (5:1) as eluent. The solvent was removed, and the product was obtained as colorless crystals. Yield 0.23 g (87%); mp 98 ˚C. IR (KBr): 3252 (OH), 1609, 1585, 1563, 1551, 1487, 1408, 1375, 1238, 1124, 1092, 1043, 1007, 841, 727 cm-¹. ¹H NMR (500.1 MHz, DMSO-d 6): δ = 1.53 (d, J = 6.6 Hz, 3 H, CH3), 4.99 (m, 1 H, CHCH3), 6.04 (d, J = 5.6 Hz, 1 H, OH), 7.65 (d, J = 8.5 Hz, 2 H, 2 × CH), 7.98 (d, J = 8.5 Hz, 2 H, 2 × CH). ¹³C NMR (125.8 MHz, DMSO-d 6): δ = 20.87 (CH3), 60.33 (CH), 122.29 (C), 128.29 and 129.61 (2 × CH), 136.71 (C), 163.23 and 168.81 (2 × OC=N). MS: m/z (%) = 270 (2) [M+ 8¹Br], 268 (2) [M+ 79Br], 244 (16), 224 (97), 209 (24), 181 (72), 152 (40), 139 (100), 125 (20), 111 (56), 89 (18), 75 (36). Anal. Calcd for C10H9BrN2O2 (269.10): C, 44.63; H, 3.37; N, 10.41. Found: C, 44.5; H, 3.5; N, 10.2.
2-[4-(Dimethylamino)phenyl]-5-(1-hydroxypropyl)-1,3,4-oxadiazole (5e)
Yield 0.21 g (80%); colorless crystals; mp 118 ˚C. IR (KBr): 3219 (OH), 1610, 1582, 1553, 1502, 1433, 1371, 1198, 1173, 1128, 1085, 1014, 968, 810 cm-¹. ¹H NMR (500.1 MHz, DMSO-d 6): δ = 0.89 (t, J = 7.4 Hz, 3 H, CH2CH 3), 1.27-1.47 (m, 2 H, CH2), 1.78-1.84 (m, 2 H, CH2), 2.98 [s, 6 H, N(CH3)2], 4.75-4.80 (m, 1 H, CH), 5.93 (d, J = 5.7 Hz, 1 H, OH), 6.80 (d, J = 8.9 Hz, 2 H, 2 × CH), 7.76 (d, J = 8.9 Hz, 2 H, 2 × CH). ¹³C NMR (125.7 MHz, DMSO-d 6): δ = 13.55 (CH3), 17.98 and 36.57 (2 × CH2), 39.56 [N(CH3)2], 63.87 (CH), 109.89 (C), 111.72 and 127.65 (2 × CH), 152.20 (C), 164.48 and 166.79 (2 × OC=N). MS: m/z (%) = 261 (100) [M+], 218 (24), 188 (3), 160 (8), 146 (54), 132 (6), 118 (5), 105 (4), 91 (3), 77 (5). Anal. Calcd for C14H19N3O2 (261.32): C, 64.35; H, 7.33; N, 16.08. Found: C, 64.2; H, 7.4; N, 16.0.
5-[1-Hydroxy-1-(3-nitrophenyl)methyl-2-(4-methoxy-phenyl)-1,3,4-oxadiazole (5g)
Yield 0.28 g (85%); colorless crystals; mp 148 ˚C. IR (KBr): 3190 (OH), 1614, 1591, 1537, 1504, 1477, 1442, 1350, 1265, 1174, 1049, 1022, 833, 800, 732 cm-¹. ¹H NMR (500.1 MHz, DMSO-d 6): δ = 3.82 (s, 3 H, OCH3), 6.29 (d, J = 6.2 Hz, 1 H, CH), 7.11 (d, J = 8.7 Hz, 2 H, 2 × CH), 7.12 (d, J = 6.2 Hz, 1H, OH), 7.71 (t, J = 7.9 Hz, 1 H, CH), 7.90 (d, J = 8.7 Hz, 2 H, 2 × CH), 7.97 (d, J = 7.6 Hz, 1 H, CH), 8.21 (d, J = 8.0 Hz, 1 H, CH), 8.41 (s, 1 H, CH). ¹³C NMR (125.8 MHz, DMSO-d 6): δ = 55.46 (OCH3), 65.32 (CH), 114.87 (CH), 115.39 (C), 121.23, 123.03, 128.38, 129.97 and 133.27 (5 × CH), 141.59 and 147.80 (2 × C), 162.11 (CO), 164.36 and 166.18 (2 × OC=N). MS: m/z (%) = 327 (54) [M+], 175 (91), 150 (13), 133 (100), 104 (15), 92 (14), 76 (28). Anal. Calcd for C16H13N3O5 (327.30): C, 58.72; H, 4.00; N, 12.84. Found: C, 58.7; H, 3.9; N, 12.8.
2-(9-Anthryl)-5-[1-hydroxy-1-(2-naphthyl)methyl]-1,3,4-oxadiazole (5i)
Yield 0.32 g (80%); colorless crystals; mp 176 ˚C. IR (KBr): 3250 (OH), 1601, 1566, 1550, 1508, 1454, 1415, 1375, 1269, 1175, 1142, 1082, 1003, 991, 889, 727 cm-¹. ¹H NMR (500.1 MHz, DMSO-d 6): δ = 6.44 (d, J = 4.4 Hz, 1 H, CH), 7.06 (d, J = 4.4 Hz, 1 H, OH), 7.48-7.60 (m, 6 H, 6 × CH), 7.73 (d, J = 8.4 Hz, 1 H, CH), 7.79 (d, J = 8.3 Hz, 2 H, 2 × CH), 7.91-8.00 (m, 3 H, 3 × CH), 8.15 (s, 1 H, CH), 8.20 (d, J = 8.0 Hz, 2 H, 2 × CH), 8.92 (s, 1 H, CH). ¹³C NMR (125.8 MHz, DMSO-d 6): δ = 66.77 (CH), 116.40 (C), 124.25, 124.55, 125.38, 125.89, 126.34, 126.41, 127.58, 127.97, 128.12, 128.13, 128.89 and 130.42 (12 × CH), 130.44, 131.66, 132.72, 132.75 and 136.99 (5 × C), 162.47 and 168.64 (2 ×˚C=N). MS: m/z (%) = 402 (89) [M+], 246 (7), 218 (7), 203 (100), 190 (16), 177 (16), 157 (54), 129 (49). Anal. Calcd for C27H18N2O2 (402.45): C, 80.58; H, 4.51; N, 6.96. Found: C, 80.7; H, 4.3; N, 6.8.