The crystal structures of L-citrulline hydrochloride and L-homocitrulline hydrochloride

Abstract

The crystal structures of L-citrulline hydrochloride and its homologue L-homocitrulline hydrochloride have been determined using diffractometer data. L-Citrulline hydrochloride: NH2CONH(CH2)aCH(NH+)COOH.C1 -, monoclinic, C2, a=18.089, b=5-150, c=11.918 ,~, fl= 106.9 °, R=0.040, the average e.s.d, of the bond distances 0-005/~. L-Homocitrulline hydrochloride: NH2CONH(CH2)4CH(NH+)COOH.C1 -, orthorhombic, P212121, a= 10.518, b=21.627, c=4.916 ,~, R=0.069, the average e.s.d, of the bond distances 0.008 /~. There is a close similarity between the dimensions of the citrulline and homocitrulline molecules in the two crystals. Also there are several common features in the two hydrogen bond schemes. The present L-citrulline HCI structure is compared with that reported previously (Naganathan & Venkatesan, Acta Cryst. (1971), B26, 790), and some significant differences between the two results are pointed out.

On the Polymorphism of l-Citrulline: Crystal Structure and Characterization of the Orthorhombic δ Form

“…In the review by Curis et al, several crystal structures of l -citrulline, a zwitterion, have been listed comprising one anhydrous crystal structure, one dihydrate, , and three salts with l -citrulline: a hydrochloride, , a perchlorate, and a co-crystal with l -malic acid . Another salt, l -citrulline oxalate monohydrate, has been published recently .…”