948. Correlation of the configurations of α-methyl-β-alanine and methylsuccinic acid

Abstract

Notes 5131948. Correlation of the ConJigurations of a-Methyl-p-alanine and Methylsuccinic AcidBy K. BALENOVIC and N. BREGANT CORRELATION of the configurations of (-)-a-methyl-P-alanine (I) and (-)-2-methylbutanol by way of (+)-2-methyl-l-phthalimidobutane, described previously,l indicated the (R)-configuration for this amino-acid.showed that the optical purity of the 2-methyl-l-phthalimidobutane obtained by Raney nickel desulphurisation of (+)-2-methyl-l-phthalimidobutan-3-one ethylene mercaptol depended strongly on the nature of the catalyst, and another method for establishing the configuration of (I) was therefore desirable.CHZNH, rR However, our later experiments

Asymmetric hydrogenation of the C–C double bond of 1- and 1,2-methylated maleimides with cultured suspension cells of Marchantia polymorpha

“…Biotransformation of N-substituted maleimides, 1-4, by cultured cells of M. polymorpha (7), obtained by the biotransformation of N-substituted 2-methylmaleimides, were dextro-rotatory. Since the optical rotation of (R)-2-methylsuccinimide derivative was reported to be dextro-rotatory, 6,7 absolute configurations of the products, 6 and 7, should be R. The peak analyses of the 1 H-NMR with chiral shift reagent 8 and the GLC with chiral column showed the enantiomeric purities of 6 and 7 to be 99% e.e. (8) and N-p-methoxyphenyl-2,3-dimthylsuccinimide (9), had 2R,3Rconfiguration, because the optical rotation of (2R,3R)-2,3-dimethylsuccinimide was reported to be dextrorotatory.…”

Asymmetric Reduction of Activated Alkenes by Pentaerythritol Tetranitrate Reductase: Specificity and Control of Stereochemical Outcome by Reaction Optimisation

“…(R)‐N‐Phenyl‐2‐methylsuccinimide (1b) was synthesised enzymatically at 50 mL scale according to general procedure 2 (36 h) as a white solid; yield: 98%; mp 133–134 °C (lit. mp 132–134 °C);36 1 H NMR (500 MHz, CDCl 3 ): δ =1.45 (d, J =7.2 Hz, 3 H), 2.50 (dd, J =4.3 Hz, J =17.6 Hz, 1 H), 2.98–3.13 (m, 2 H), 7.26–7.50 (m, 5 H); 13 C NMR (100 MHz, CDCl 3 ): δ =16.9, 34.8, 36.6, 126.4, 128.6, 129.1, 131.9, 175.4, 179.5; [α] D : +9.90 ( c 1.01, CHCl 3 ) lit. +6.6 (c 0.56, CHCl 3 );37 >99% ee (Chiralcel OD: hexane/ i‐ PrOH, 9:1, t R =53.5 min, t s =63.0 min); anal.…”

Effects of Chirality on the Antifungal Potency of Methylated Succinimides Obtained by Aspergillus fumigatus Biotransformations. Comparison with Racemic Ones

“…The structures of 3 – 10 were corroborated by MS and 1 H- and 13 C-NMR. To assist in the assignment of both the absolute configuration and the ee of each chiral succinimide, R -enantiomers of 3 – 10 were also synthesized from ( R )-2-methylsuccinic acid 19 and the respective anilines 20 – 27 ( Scheme 2 ) [ 17 ]. Synthetic (3 R )- 3 - 10 were all dextrorotatory, therefore indicating that the biotransformation products (+)- 3 - 10 had the R -configuration.…”