6001-74-7Relevant articles and documents
Process for the preparation of 4-methyl-5-(2-chloroethyl)-thiazole and analogues thereof
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, (2008/06/13)
The present invention relates to a process for the preparation of compounds of general formula (I), wherein R stands for a straight chained C1-5 alkyl group substituted by a chlorine atom in the 2-position, and acid addition salts thereof, characterized by reacting a 3,5-dichloro-2-alkanone of general formula (V), wherein R is a defined above, with an inorganic thiocyamate, and a) converting the 3-thiocyanato-5-chloro-2-alkanone of general formula (IV), thus obtained, wherein R is as defined above, into 2-chloro-4-methyl-5-(2-chloroalkyl)-thiazole of general formula (II), wherein R is as defined above, by gaseous hydrochloric acid in an organic solvent, hydrogenating the said compound in the presence of a metal catalyst in an organic solvent, or b) reacting said compound of general formula (IV) with an aqueous mineral acid and treating the 2-hydroxy-4-methyl-5-(2-chloroalkyl)-thiazole of general formula (III), thus obtained with a halogenating agent, and hydrogenating the 2-chloro-4-methyl-5-(2-chloroalkyl)-thiazole of general formula (II) thus obtained, wherein R is as defined above, in an organic solvent in presence of a metal catalyst, and optionally converting the 4-methyl-5-(2-chloroalkyl)-thiazole of general formula (I), wherein R is as defined above, thus obtained or a hydrochloride salt thereof, in a manner known per into another acid addition salt or setting free a compound of general formula (I), wherein R is a defined above, from its acid addition salt.
New 1-(heterocyclylalkyl)-4-(propionanilido)-4-piperidinyl methyl ester and methylene methyl ether analgesics
Bagley,Thomas,Rudo,Spencer,Doorley,Ossipov,Jerussi,Benvenga,Spaulding
, p. 827 - 841 (2007/10/02)
A series of new 1-(heterocyclyalkyl)-4-(propionanilido)-4-piperidinyl methyl esters and methylene methyl ethers have been synthesized and pharmacologically evaluated. In the mouse hot-plate test, the majority of compounds exhibited an analgesia (ED50 1 mg/kg) superior to that of morphine. These studies revealed a pharmacological accommodation for many more structurally diverse and far bulkier aromatic ring systems than the corresponding components of the arylethyl groups of the prototypic methyl ester (carfentanil, 2) and methylene methyl ether (sufentanil, 3 and alfentanil, 4) 4-propionanilido analgesics. Compound 9A (methyl 1-[2-(1H-pyrazol-1-yl)-ethyl]-4-[(1-oxopropyl) phenylamino]-4-piperidinecarboxylate), which exhibited appreciable μ-opioid receptor affinity, was a more potent and short-acting analgesic, than alfentanil with less respiratory depression in the rat. On the other hand, the phthalimides 57A and 57B, which exhibited negligible affinity for opioid receptors associated with the mediation of nociceptive transmission (i.e., μ-, κ-, and δ-subtypes), displayed analgesic efficacy in all antinociception tests. In addition, while 57B, compared to clinical opioids, showed a superior recovery of motor coordination after regaining of righting reflex from full anesthetic doses in the rat rotorod test, 57A showed significantly less depression of cardiovascular function at supraanalgesic doses in the isoflurane-anesthetized rat.
