RTI-274

RTI-274, or 2β-((3,4-Methylenedioxyphenoxy)methyl)-3α-(4-fluorophenyl)nortropane is a phenyltropane homologue of paroxetine developed by the group led by F Ivy Carroll in the 1990s.[1]

Introduction

Very few ethers of phenyltropanes are actually known to have been reported. NS2330 and NS2359 are exemplary, although it must be stressed that these compounds have α,β stereochemistry. Since further development of NS2214 appears to have been halted, the importance of a metabolically stable compound that is not just readily metabolized is evident.

For some reason that is not entirely clear, the authors of the present document decided that they wanted to make all 8 stereoisomers for the phenyltropane homolog of paroxetine.[1]

MAT IC50 (nM) Nor/tropane-Paroxetine Hybrids
Compound [3H]CFT [3H]Paroxetine [3H]Nisoxetine
Paroxetine ? → 623 ? → 0.28 ? → 535
R "β,β" 308 → 835 294 → 480 5,300 → 37,400
α,β 172 → 142 52.9 → 90 26,600 → 2,500
β,α 3.01 → 3.86 422 → 5.62 123 → 14.4
S "β,β" 1,050 → 1,210 88.1 → 424 27,600 → 17,300
α,β 1,500 → 27.6 447→ 55.8 2,916 → 1,690
β,α 298 → 407 178 → 19 12,400 → 1,990
  • N-demethylating the S-α,β (1S,2S,3R) isomer resulted in a 54-fold increase in DAT IC50.

In the case of nocaine it is understood that the SR enantiomer is the one that should be demethylated if it is wanted to improve DAT affinity.

Interestingly, that is actually the same enantiomer that is used in the production of paroxetine.

Skeletal Rearrangement

Four years later some unrelated authors cited a skeletal rearrangement accounts for this.Diagram

Notice that they are not only interested in ethers, but nitrogen containing Nu's ("TRODAT") {p948, 24}.

The metal is called "Technetium" and is bound by a chelating agent.

The authors state that at first the acid is halogenated, the amide is prepared, and reduced.

Erratum

MAT IC50 (Ki) N-Methyl → De-methyl
Compound [3H]CFT [3H]Nisoxetine [3H]paroxetine
R-β,β ? → 3 ? → 2 (0.2) ? → 6 (4)
S-β,β ? → ? ? → ? (?) ? → ? (?)
R-"nonane" 308 → 835 294 (27) → 480 (44) 5,300 (3200) → 37,400 (22,500)
S-"nonane" 1050 → 1210 88 (8) → 424 (39) 27,600 (16,600) → 17,300 (10,400)
File:Taxil.gif

To solve the problem of the unexpected aza-bicyclo[3.2.2]nonane rearrangement product, the original synthesis had to be modified as follows;[3] WIN 35428 was N-demethylated and then the NH amine was reacted with a suitable protecting group so that is no longer nucleophilic. In their case they used a tosyl. (Satendra Singh, 2000) Page 952

See also

References