Synthesis of trans‐[13,14‐¹⁴C₂]‐retinoic acid

Abstract

Trans‐[13,14‐14C2]‐Retinoic acid has been synthesized by condensation of β‐ionylideneacetaldehyde and 14C‐labeled methyl senecioate in the presence of potassium amide in ether. A convenient synthesis of the key intermediate, methyl (diethoxyphosphinyl)‐[2‐14C]acetate, is also described.

Model Compounds for Rhodospin and Bacteriorhodopsin: Synthesis, and 1H‐ and 13C‐NMR Study

“…The models compounds synthesized do not provide any further information about the 'opsin shift' since their chemical shifts are not very different from, for example, those of the N-butylretinal iminium salts. The result from addition of lithium perchlorate to zwitterionic solutions is supported by the work of Nakanishi et al position is obviously necessary, and is certainly possible [30]. Two similar experiments have been undertaken [9] [lo], both involving retinals (embedded in rhodopsin or bacteriorhodopsin) enriched with I3C at C( 14) and C( 15)-positions.…”

Preparation of Carbon‐14‐Labeled Compounds via Multi‐Carbon Building Blocks of the [ 14 C]Carbon Dioxide Tree

“…The latter pathway has been followed for the carbon-14 labeling of SK&F 104353 (110). MeONa, NaNH 2 , tert-BuONa) furnishes a,b-epoxy [ 14 C]esters ([ 14 C]glycidic esters).…”

“…In the simplest case, alkylation of deprotonated 159 with methyl iodide furnishes the homologous propionate reagent 175, which has been employed as a starting material in the synthesis of [ 14 C]E-5090 (179), an orally active IL-1 inhibitor. Upon ester hydrolysis followed by fractional crystallization from methanol, (all-E)-[13; 14-14 C 2 ]retinoic acid (185) was isolated in 25% radiochemical yield 110 . It adds as a vinologous ester in an aldol-like condensation reaction, for example, to b-ionylideneacetaldehyde (184) to give a 2:1-mixture of ethyl (13E)-and (13Z)-retinoates.…”

“…74 Applications of tertiary [1-14 C ]alcoholsThe synthesis of trans-[13-14 C]retinoic acid (265) (Procedure B) may serve as an additional example of the use of an [ 14 C]acetone-based building block. Upon deprotonation, this coupled with b-ionylideneacetaldehyde (264) to provide 265, thereby extending the carbon skeleton of 264 again by a labeled five-carbon unit110 . Upon deprotonation, this coupled with b-ionylideneacetaldehyde (264) to provide 265, thereby extending the carbon skeleton of 264 again by a labeled five-carbon unit110 .…”