- Asymmetric strecker-type reaction of α-aryl ketones. Synthesis of (S)- αM4CPG, (S)-MPPG, (S)-AIDA, and (S)-APICA, the antagonists of metabotropic glutamate receptors
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Heating a mixture of α-aryl ketone with (R)-phenylglycinol produces a mixture of imine and 1,3-dioxazolidine. Treatment of this mixture with trimethylsilyl cyanide followed by transformation of nitrile to ester gives Strecker-type reaction products. The diastereoselectivity of the generated α-amino esters is from 2/1 to 7/1, and the (R,S)isomer is found as the major product. The (R,S) and (R,R)isomers can be separated by conversion to their N-Cbz or cyclization derivatives. Using this methodology, four antagonists of metabotropic glutamate receptors, (S)-αM4CPG, (S)-MPPG, (S)AIDA, and (S)- APICA, are synthesized.
- Ma, Dawei,Tian, Hongqi,Zou, Guixiang
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p. 120 - 125
(2007/10/03)
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- Stereoselective synthesis of (S)-MPPG, (S)-MTPG and (S)-(+)-αM4CPG from (R)-4-hydroxyphenylglycine
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(R)-4-Hydroxyphenylgrycine was protected with a benzyl group and a methyl group was introduced at the α position by using the self-regeneration-of-stereocentre method. After the 4-hydroxy group had been converted into the corresponding trifluoromethanesulfonate (triflate), three palladium-catalyzed reactions were employed to furnish (S)-α-methyl-4-phosphonophenylglycine [(S)-MPPG], (S)-α-methyl-4-(tetrazol-5-yl)phenylglycine [(S)-MTPG] and (S)-4-carboxyphenyl-α-methylglycine [(S)-αM4CPG], a class of new and selective antagonists of metabotropic glutamate receptors.
- Ma, Dawei,Tian, Hongqi
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p. 3493 - 3496
(2007/10/03)
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