Crystals of alanine N-acetic acid precursors, process to prepare them and their use

An alanine N-acetic acid precursor selected from the group consisting of:

• (a) alanine N-monoacetonitrile of formula COOM-CH(CH3)—NH—(CH2CN), wherein M is hydrogen, said alanine N-monoacetonitrile showing X-ray diffraction reflections at 28=13.3;
• 20.3;
• 21.4;
• 21.9;
• 24.0 with an accuracy of ±0.1,
• (b) alanine N,N-diacetonitrile and its partial sodium salts of formula COOM-CH(CH3)—N—(CH2CN)2, wherein greater than 0 to 50% of all M is sodium and 50 to less than 100% of all M is hydrogen comprising L-alanine N,N-diacetonitrile to D-alanine N,N-diacetonitrile, or their respective partial sodium salts, in a range of from 75:25 to 50:50 (L:D), said alanine N,N-diacetonitrile partial sodium salts showing X-ray diffraction reflections at 28=7.1;
• 10.8;
• 14.3;
• 14.8;
• 18.2;
• 20.7;
• 21.0;
• 23.3 with an accuracy of ±0.1, and
• (c) alanine N,N-diacetamide of formula COOM-CH(CH3)—N—(CH2CONH2)2, wherein M is hydrogen,
• and wherein the precursors is in the form of crystals that exhibit interference in monochromatic X-ray diffraction which fulfills the Bragg equation 2d sin θ=nλ.