- Preparation method of tetramisole intermediate hydroxysalt
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The invention relates to a preparation method of a tetramisole intermediate hydroxysalt in the technical field of broad-spectrum anthelmintics. The method comprises the following steps of: adding an aprotic solvent, acetophenone and inorganic base into a reaction device, performing heating, and stirring the substances uniformly; then adding 2-chloroethylamine hydrochloride into the reaction devicein batches, continuously carrying out heat preservation reaction, performing cooling and filtering after the reaction is finished, and carrying out vacuum concentration on filtrate to remove the solvent to obtain an oily compound; and adding water and the oily compound into a reaction device, adjusting the pH value by using hydrochloric acid to dissolve and clarify the material, adding thiourea,performing heating, distilling and concentrating until the internal temperature reaches 108-110DEG C, further carrying out reflux reaction, conducting cooling, crystallizing and filtering after the reaction is finished, washing the filter cake by using 95% ethanol, further performing filtering and drying, and drying the solid to obtain the hydroxysalt. The yield of the hydroxysalt can reach 90% orabove, the purity can reach 99% or above, the content can reach 98% or above, the preparation is convenient, the process is simple, and the method is an alternative method for industrial production of the hydroxysalt and tetramisole.
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Paragraph 0017; 0020-0024; 0027-0029; 0032-0034; 0037-0039
(2021/01/20)
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- A short synthesis of [14C]-labelled levamisole and its major metabolite
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Levamisole (I) is the levo isomer of tetramisole. It is a broad spectrum anthelmintic which is used extensively as a veterinary drug for food producing animals. Metabolism and environmental studies necessitated the synthesis of 14C-labelled levamisole (6) and of its major metabolite (12). 14C-Tetramisole was obtained in two steps from 14C-thiourea. Resolution via salt formation and crystallization afforded 14C-levamisole and 14C-dexamisole. Racemisation followed again by resolution made it possible to improve the over-all radiochemical yield of 14C-levamisole to 51.0%. The compound had a specific activity of 73.6 MBq/mmol, a HPLC purity of 99.8% and an enantiomeric excess of 99.4%. The 14C-labelled metabolite of levamisole (II) was obtained from 14C-potassium cyanate in 4 consecutive steps. Resolution via chiral HPLC afforded the desired compound in a 16.2% overall radiochemical yield. It had a specific activity of 895 MBq/mmol, a HPLC purity of 98.7% and an enantiomeric excess of 100%. Copyright
- Janssen, Cor G.M.,Thijssen, Jos B.A.,Verluyten, Willy L.M.
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p. 591 - 600
(2007/10/03)
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- EFFICIENT ASYMMETRIC HYDROGENATION OF α-AMINOACETOPHENONE DERIVATIVES LEADING TO PRACTICAL SYNTHESIS OF (S)-(-)-LEVAMISOLE
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The neutral (2S,4S)-MCCPM-rhodium complex was found to be an efficient catalyst for asymmetric hydrogenation of α-aminoacetophenone derivatives.A practical asymmetric synthesis of (S)-(-)-levamisole was realized by using this hydrogenation as a key reaction.
- Takeda, Hideo,Tachinami, Takeshi,Aburatani, Masakazu,Takahashi, Hisashi,Morimoto, Toshiaki,Achiwa, Kazuo
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p. 363 - 366
(2007/10/02)
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- Method of preparing dl 6-phenyl-2,3,5,6-tetrahydroimidazo-[2,1-b]thiazole and acid addition salts thereof
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An improved method of preparing acid addition salts of dl 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole (dl-tetramisole) by reacting dl-3-(β-hydroxyphenethyl)-2-iminothiazolidine or an acid-addition salt thereof, with a mixture of concentrated hydroch
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- Process for preparing 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole
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This disclosure relates to a process for the manufacture of compounds of the formula STR1 which comprises ring-closing a compound of the formula STR2 wherein the variables are as defined infra.
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