A novel practical method for the synthesis of N-methyl-DL-aspartic acid 1 (NMA) and new syntheses for N-methyl-aspartic acid derivatives are described. NMA 1, the natural amino acid was synthesized by Michael addition of methylamine to dimethyl fumarate 5. Fumaric or maleic acid mono-ester and -amide were regioselectively transformed into beta-substituted aspartic acid derivatives. In the cases of maleamic 11a or fumaramic esters 11b, the alpha-amide derivative 13 was formed, but hydrolysis of the product provided N-methyl-DL-asparagine 9 via base catalyzed ring closure to DL-alpha-methylamino-succinimide 4, followed by selective ring opening. Efficient methods were developed for the preparation of NMA-alpha-amide 13 from unprotected NMA via sulphinamide anhydride 15 and aspartic anhydride 3 intermediate products. NMA diamide 16 was prepared from NMA dimethyl ester 6 and methylamino-succinimide 4 by ammonolysis. Temperature-dependent side reactions of methylamino-succinimide 4 led to diazocinone 18, resulted from self-condensation of methylamino-succinimide via nucleophyl ring opening and the subsequent ring-transformation.

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The three new Reinecke salt like complexes (III) are obtained in a substitution reaction of anhydrous (I) with the corresponding amines (II).

Drei neue Reineckesalz‐ähnliche Komplexe [Cr(NCS)4(Amin)2]−, wurden durch Substitutionsreaktionen aus entwässertem K3[Cr(NCS)6] und Triethyl‐, Tripropyl‐, bzw. Tributylamin ohne Verwendung von Lösungsmitteln erhalten. Die Herstellung von 63 neuen Salzen mit den Chlorhydraten einiger aliphatischer Amine und Alkaloide, bzw. mit Metallen und Kobalt(III)‐Aminen bestätigt die Zusammensetzung der erwähnten einbasischen Komplexanionen. Zur Klärung einiger Strukturfragen wurden die elektronischen und IR‐Spektren einiger Derivate aufgenommen und diskutiert.