Asymmetric alpha-substituted phenethylamines. VI. Synthesis and analgesic activity of optically pure (R)- and (S)-N-alkyl-1-cyclohexyl-2-phenylethylamines

2-Phenethylamines in Medicinal Chemistry: A Review

A concise review covering updated presence and role of 2-phenethylamines in medicinal chemistry is presented. Open-chain, flexible alicyclic amine derivatives of this motif are enumerated in key therapeutic targets, listing medicinal chemistry hits and appealing screening compounds. Latest reports in discovering new bioactive 2-phenethylamines by research groups are covered too.

Diastereoselective Arylithium Addition to an α-Trifluoromethyl Imine. Practical Synthesis of a Potent Cathepsin K Inhibitor

A practical, chromatography-free synthesis of potent cathepsin K inhibitor 1 is described. The addition of 4-bromophenyllithium to an alpha-trifluoromethylimine derived from commercially available (S)-leucinol was accomplished in a highly diastereoselective manner (97.6% de, 91% yield). Subsequent Suzuki cross-coupling afforded biaryl 7. Oxidation of the alcohol and sulfide functionalities led to the formation of carboxylic acid 8. Crystallization of 7 and acid 8 as its dicyclohexylamine salt gave excellent impurity rejection. The final amide coupling with commercially available aminoacetonitrile hydrochloride afforded 1 in excellent purity (99.6A% by HPLC, 100% de, <3 ppm Pd, W, Cr).

Synthesis and evaluation of cyclic secondary amine substituted phenyl and benzyl nitrofuranyl amides as novel antituberculosis agents

In an ongoing effort to develop new and potent antituberculosis agents, a second-generation series of nitrofuranyl amides was synthesized on the basis of the lead compound 5-nitrofuran-2-carboxylic acid 3,4-dimethoxybenzylamide. The primary design consideration was to improve the solubility and consequently the bioavailability of the series by the addition of hydrophilic rings to the benzyl and phenyl B ring core. The synthesis of 27 cyclic, secondary amine substituted phenyl and benzyl nitrofuranyl amides is described and their activity against Mycobacterium tuberculosis reported. The series showed a strong structure-activity relationship as the benzyl nitrofuranyl amides were significantly more active than similarly substituted phenyl nitrofuranyl amides. Para-substituted benzyl piperazines showed the most antituberculosis activity. Compounds in the series were subsequently selected for bioavailability and in vivo testing. This study led to the successful discovery of novel compounds with increased antituberculosis activity in vitro and a better understanding of the requisite pharmacological properties to advance this class.

Oxazolidine Ring Opening and Isomerization to (E)-Imines. Asymmetric Synthesis of Aryl-α-fluoroalkyl Amino Alcohols

[reaction: see text] A base-induced ring opening/imine isomerization/diastereoselective organometallic addition sequence on 4-substituted 2-perfluoroalkyl-1,3-oxazolidines has been developed for the asymmetric synthesis of aryl alpha-perfluoroalkylamine derivatives. This practical method provides chiral amino alcohols in 60-95% yield with uniformely high diastereoselectivities ranging from 35:1 to >100:1.

Diastereoselective Synthesis of N-Substituted Ethyl 4-Phenyloxazolidine-2-carboxylates

( S)-2-Phenylglycinol, ethyl glyoxylate, formaldehyde and benzotriazole formed stereospecifically ethyl (2 S,4 S)- N-(benzotriazol-1-yl)methyl-4-phenyloxazolidine-2-carboxylate (1) which was converted into chiral N-substituted oxazolidines, via regiospecific substitutions of the benzotriazolyl residue.