A Simple Reduction Method of Azo-Compounds
757
1
cmꢂ1; H NMR (300MHz, DMSO-d6): ꢁ ¼ 4.92 (bs, NH2),
7.03 (m, 2CHaromatic), 7.17 (m, 1CHaromatic), 7.26 (m,
1CHaromatic), 7.63 (m, 1CHaromatic), 7.91 (m, 1CHaromatic),
9.17 (bs, OH) ppm; 13C NMR (300MHz, DMSO-d6: ꢁ ¼
118.60, 119.31, 120.82, 123.62, 123.48, 125.65, 125.32,
128.35, 129.63, 136.75 ppm.
groups, which are easily destroyed during catalytic hy-
drogenation. Ethanol as co-solvent of water and was
necessary for the reaction due to solubility of reactants.
In conclusion, this study led to the development of
a one-step synthetic strategy of amines involving
reduction of azo-compounds in the presence of Fe
powder and ammonium chloride.
2-Amino-4-fluorophenol hydrochloride (2h, C6H7ClFNO)
Colorless solid, mp>200ꢁC (dec); IR (KBr): ꢀꢀ¼ 3361 (OH),
3217–3184 (NH2), 3023 (CHaromatic), 1626 (C¼Caromatic
)
Experimental Section
cmꢂ1
;
1H NMR (300 MHz, DMSO-d6): ꢁ ¼ 4.79 (bs,
1H NMR spectra were recorded on a Bruker (300 MHz) spec-
trometer. The IR spectra were recorded on a Galaxy FT-IR 300
spectrophotometer. Microanalyses were performed by the
Elemental Analyzer (Elementar, Vario EL III); their results
agreed favorably with calculated values. Reaction courses
and product mixtures were monitored by thin layer chromato-
graphy. All starting materials were obtained from Fluka and
Merck companies.
NH2), 6.08 (m, 1CHaromatic), 6.33 (m, 1CHaromatic), 6.52 (m,
1CHaromatic), 8.91 (bs, OH) ppm; 13C NMR (300 MHz,
DMSO-d6: ꢁ ¼ 100.90, 114.56, 138.53, 140.55, 155.30,
158.37 ppm.
2-Amino-4-ethylphenol hydrochloride (2i, C8H12ClNO)
Colorless solid, mp>200ꢁC (dec); IR (KBr): ꢀꢀ¼ 3261,
3317 (NH2), 3133 (CHaromatic), 2965, 2895 (CHaliphatic),
1
1626 (C¼Caromatic) cmꢂ1; H NMR (300MHz, DMSO-d6):
ꢁ ¼ 1.06 (t, CH3), 2.38 (q, CH2), 4.40 (bs, NH2), 6.21 (m,
1CHaromatic), 6.43–6.50 (m, 2CHaromatic), 8.67 (bs, OH) ppm;
13C NMR (300 MHz, DMSO-d6: ꢁ ¼ 16.55, 28.13, 114.97,
118.23, 118.48, 120.23, 135.41, 139.62ppm.
General Procedure
A mixture of 0.5 g ammonium chloride (0.01 mol), 100 cm3
H2O=EtOH, and 0.01mol appropriate azo-compound was
placed in a 250 cm3 beaker. The mixture was stirred vigor-
ously and 0.11 g Fe powder (2mmol) were added. The tem-
perature was slowly raised to the boiling point of the solvent.
The stirring was continued for a further 15min in an efficient
fume cupboard. By that time the reduction is complete as
indicated by the mixture becoming colorless again. The warm
reaction mixture was then filtered to separate the product.
4-Aminonaphthalen-1-ol hydrochloride (2j, C10H10ClNO)
Colorless solid, mp>200ꢁC (dec); IR (KBr): ꢀꢀ¼ 3317 (OH),
3296–3261 (NH2), 3142 (CHaromatic), 1626, 1515 (C¼Caromatic
)
cmꢂ1
;
1H NMR (300 MHz, DMSO-d6): ꢁ ¼ 4.99 (bs,
NH2), 6.50 (d, 1CHaromatic), 6.61 (d, 1CHaromatic), 7.29 (m,
2CHaromatic), 7.93(m, 2CHaromatic), 9.01(s, OH) ppm; 13C NMR
(300MHz, DMSO-d6: ꢁ ¼ 108.62, 109.31, 118.76, 122.56,
122.82, 124.60, 124.98, 125.58, 137.06, 144.46ppm.
N,N-Dimethylbenzene-1,4-diamine hydrochloride
(2a, C8H13ClH2)
Colorless solid, mp>200ꢁC (dec); IR (KBr): ꢀꢀ¼ 3357–3221
References
(NH2), 3123 (CHaromatic), 2963 (CHaliph), 1615 (C¼Caromatic),
1
1212 (C–N) cmꢂ1; H NMR (300 MHz, DMSO-d6): ꢁ ¼ 2.68
[1] Watthey JWH, Stanton JL, Desai M, Babiarz JE, Finn
BM (1985) J Med Chem 28: 1511
(s, 2CH3), 5.15 (bs, NH2), 6.42 (d, 1CHaromatic), 6.48 (d,
1CHaromatic), 6.57 (d, 1CHaromatic), 7.23 (d, 1CHaromatic) ppm;
13C NMR (300MHz, DMSO-d6: ꢁ ¼ 40.50, 112.67, 115.56,
117.33, 127.11 ppm.
[2] Ksander GM, Erion M, Ruan AM, Diefenbacher CG, E1-
chehabi L, Cote D, Levens N (1994) J Med Chem 37: 1823
[3] Parsons WH, Davidson JL, Taub D, Aster SD, Thorsett
ET, Patchett AA (1983) Biochem Biophys Res Commun
117: 108
4-Amino-2,6-dichlorophenol hydrochloride (2c, C6H6Cl3NO)
Colorless solid, mp>200ꢁC (dec); IR (KBr): ꢀꢀ¼ 3233–
[4] Boyer SK, Pfund RA, Portmann RE, Sedelmeier GH,
Wetter HF (1988) Helv Chim Acta 71: 337
3159 (NH2), 3104 (CHaromatic), 1586 (C¼Caromatic) cmꢂ1
;
1H NMR (300 MHz, DMSO-d6): ꢁ ¼ 5.00 (bs, NH2), 6.55
(m, 2CHaromatic), 8.79 (s, OH) ppm; 13C NMR (300 MHz,
DMSO-d6: ꢁ ¼ 114.06, 123.94, 139.29, 143.40ppm.
[5] (a) Shieh W-C, Carlson JA, Zaunius GM (1987) J Org
Chem 62: 8271; (b) Schoen WR, Pisano JM, Prendergast
K, Wyvratt MJ Jr, Fisher MH, Cheng K, Chan WW-S,
Butler B, Smith RG, Ball RG (1994) J Med Chem 37: 897
[6] (a) Watthey JWH, Chappaqqua NY (1984) US. Patent
4473575 (1985) Chem Abstr 102: 113326; (b) Attwood
2-Amino-1,3-benzenediol hydrochloride (2d, C6H8ClNO2)
Colorless solid, mp>200ꢁC (dec); IR (KBr): ꢀꢀ¼ 3382 (OH),
3321–3254 (NH2), 3132(CHaromatic), 1613(C¼Caromatic) cmꢂ1
;
¨
MR, Hassall CH, Krohn A, Lawton G, Redshaw S
1H NMR (300MHz, DMSO-d6): ꢁ ¼ 4.98 (bs, NH2), 6.47
(m, 3CHaromatic), 6.96 (bs, 2OH) ppm; 13C NMR (300 MHz,
DMSO-d6: ꢁ ¼ 114.30, 116.06, 129.25, 149.26ppm.
(1986) J Chem Soc Perkin Trans 1: 1011
[7] Pojer MP (1978) Aust J Chem 32: 201
[8] Sridhara MB, Srinivasa SR, Gowda DC (2004) J Chem
Res (s) 74
1-Aminonaphthalen-2-ol hydrochloride (2f, C10H10ClNO)
Colorless solid, mp>200ꢁC (dec); IR (KBr): ꢀꢀ¼ 3325 (OH),
[9] Wenqing L, Xiaomei Z, Ze H, Yi J, Liuzhu G, Aiqiao M
(2002) Synth Commun 32: 3279
[10] Scriven EFV, Turnbull K (1988) Chem Rev 88: 351
3295–3212 (NH2), 3085(CHaromatic), 1626, 1465 (C¼Caromatic
)