1-(3,4-dimethoxyphenyl)ethanol
Geza Arvai,
http://www.google.com/patents/WO1999006343A1?cl=en
Example 1.
Into a 10-L hydrogenation vessel, equipped with an internal coil for heating and cooling, stirrer, manometer and thermometer, 3.5 kg (19,4 mol) of 3,4-dimethoxy- acetophenone are placed and to it 0.26 kg (0,074 mass part) slurry of finely- powdered Raney-nickel (pH=8-9) promoted catalyst are washed with 1 kg of water. The reactor is filled with 3.5 kg of water, flushed with nitrogen, then with hydrogen, and under intensive stirring (revolution per minute is approx. 1420 min"1) the mixture is reacted at 70-85°C with hydrogen under 8-10 bar. After 7 hours the hydrogen consumption is ceased. Closing the hydrogen inlet, the reaction is post- hydrogenated for half an hour, then it is cooled. The catalyst is removed by filtration. The filtrate is concentrated in vacuo (20 torr) by a rotary evaporator, in a 40-50°C water-bath. The product is a yellow viscous oil, weight 3.48 kg (19, 1 mol, 98,5%). Refractive index (NaD, 25°C) is 1,5385; assay by HPLC is 97,3%; water content by Karl-Fisher method is 1,2%. TLC (Kieselgel 60 F25 benzene-EtAc 7:3 v/v) shows one spot (Rf=0.28, visualized by UV light and PMA).
An aliquot part is crystallized from 1.5-fold volume of diethyl ether - light petroleum (2:1, v/v) mixture. Melting point of the thus obtained white crystals is 34- 35 °C.
Confirmation of structure
IR (KBr, cm"1) v: 3312, 3056, 3006, 2966, 2926, 2880, 2844, 1608, 1594, 1522, 1467, 1261, 1237, 1162, 1140, 1091, 1075, 1028, 861, 814.
IH-NMR (200 MHz, CDC13) δ: 1.47 (3H, d, J=6.4 Hz, CH3), 2.08 (IH, s, OH),
IH-NMR (200 MHz, CDC13) δ: 1.47 (3H, d, J=6.4 Hz, CH3), 2.08 (IH, s, OH),
3.86 and 3.88 (total 6H, each s, CH30), 4.83 (IH, q, J=6.4 Hz, CHOH), 6.79-6.93 (3H, m, aromatic).
1 C-NMR (50 MHz, CDCI3) δ: 25.05 (CH3), 55.79 and 55.89 (CH30), 70.10
(ArCH), 108.65 (C-2), 1 10.98 (C-5), 1 17.48 (C-6), 138.57 (C-l), 148.28 and 149.0 (C-3, C-4).
Literature data
Literature data
CAS No: 5653-65-6
CA name: l-(3,4-dimethoxyphenyl)-ethanol B.p. 145-150 (4 torr), refractive index (Zhur. Obshchei Khim. 27, 2142 (1957), CA 52; 8089g) (NaD 20°C) 1.5440.
• IH-NMR (200 MHz, CDC13) δ: 1.48 (d, J=6.5 Hz), 3.86 and .89 (s), 4.84 (q), 6.8-6.94 (m).
• 13c-NMR (Ann- 1977- 588) (50 MHz' CDC13) δ: 25.0, 55.8, 55.9, 70.1, 108.7, 111.1, 117.5, 138.6, 148.4, 149.1.
Geza Arvai
process chemist at Sanofi
hu.linkedin.com/pub/geza-arvai/23/90a/165
Üdvözöljük a Sanofi
magyarországi oldalán
Process for the preparation of 1-(3,4-dimethoxyphenyl)-ethanol
Europe WO9906343
Issued July 31, 1997
The subject of our invention is the process for the preparation of the 1-(3,4-dimethoxypheny)ethanol of formula (I), by the reduction of 3,4-dimethoxyacetophenone of formula (II), characterized in that the carbonyl group of the 3,4-dimethoxyacetophenone of formula (II) is reduced by 1 mol of hydrogen under the conditions of catalytic hydrogenation.
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