US 12,351,543 B2
Process for the preparation of a metastable crystal modification of N-(aminoiminomethyl)-2-aminoethanoic acid (IV)
Thomas Güthner, Trostberg (DE); Franz Thalhammer, Trostberg (DE); and Jürgen Sans, Trostberg (DE)
Assigned to Alzchem Trostberg GmbH, Trostberg (DE)
Appl. No. 17/626,648
Filed by Alzchem Trostberg GmbH, Trostberg (DE)
PCT Filed Jun. 25, 2020, PCT No. PCT/EP2020/067842
§ 371(c)(1), (2) Date Jan. 12, 2022,
PCT Pub. No. WO2021/008846, PCT Pub. Date Jan. 21, 2021.
Claims priority of application No. 10 2019 118 893.8 (DE), filed on Jul. 12, 2019; and application No. 10 2019 118 894.6 (DE), filed on Jul. 12, 2019.
Prior Publication US 2022/0289670 A1, Sep. 15, 2022
Int. Cl. C07C 279/14 (2006.01); A23K 20/142 (2016.01); C07C 277/08 (2006.01)
CPC C07C 279/14 (2013.01) [A23K 20/142 (2016.05); C07C 277/08 (2013.01); C07B 2200/13 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A process for preparing N-(aminoiminomethyl)-2-aminoacetic acid comprising N-(aminoiminomethyl)-2-aminoacetic acid in a thermodynamically metastable crystal modification, wherein the thermodynamically metastable crystal modification shows in the X-ray powder diffractogram of the crystal modification when using Cu—Kα radiation the strongest reflection bands at 2Θ=20.2° and 23.3° and 23.8° and 25.3° with a measurement accuracy of +/−0.2°, wherein N-(aminoiminomethyl)-2-aminoacetic acid is crystallized from a water-containing solution in the presence of at least one guanidine compound of formula (I), wherein formula (I) represents:

OG Complex Work Unit Chemistry
where radicals R1, R2 as well as indices m1, m2 in formula (I) independently of one another mean:
R1, R2=independently of one another hydrogen or C1 to C4 alkyl,
m1, m2=independently of one another 1, 2 or 3,
wherein the guanidine compounds of formula (I) are present in an amount of at least 0.01 wt-% (based on the total weight of the solution).