Erlotinib hydrochloride: an anticancer agent

In the cation of the title compound, C22H24N3O4 +·Cl−, an active ingredient of the anticancer drug also known as Tarceva, the quinazoline ring system is planar within 0.044 (3) Å. The dihedral angle formed by the mean planes of the two six-membered quinazoline rings is 3.2 (1)°. Both N-bound H atoms participate in N—H⋯Cl bonds, which link the ions into infinite chains running along the b axis. C—H⋯O interactions involving neighboring cations provide additional stabilization of these aggregates.

In the cation of the title compound, C 22 H 24 N 3 O 4 + ÁCl À , an active ingredient of the anticancer drug also known as Tarceva, the quinazoline ring system is planar within 0.044 (3) Å . The dihedral angle formed by the mean planes of the two six-membered quinazoline rings is 3.2 (1) . Both Nbound H atoms participate in N-HÁ Á ÁCl bonds, which link the ions into infinite chains running along the b axis. C-HÁ Á ÁO interactions involving neighboring cations provide additional stabilization of these aggregates.

Experimental
The X-ray study confirmed the molecular structure and atomic connectivity for (I), as illustrated in Fig. 1. The C21-C22 bond length [1.170 (4) Å] is consistent with its acetylenic character, as evidenced by literature value of 1.174 (11) Å (see Allen et al., 1987). The geometry of the quinazoline ring system is comparable to that in the reported related structure (Xia, 2005).
Both N-bound H atoms (HN1 and H3) participate in H-bonds with the Cl1 anion (Table 2). These bonds link cations and anions into the infinite chains running along the b axis of the crystal. The C1-H1···O4 interactions involving neighboring cations provide additional stabilization for these chains (Fig. 2).

Experimental
In order to obtain crystals suitable for X-ray study, commercially available erlotinib hydrochloride was dissolved in a methanol-water solution (90:10v/v); the solvents were then allowed to evaporate slowly.

Refinement
The acetylenic H22 atom was located in a difference Fourier map and refined isotropically [C22-H22 0.95 (3) Å]; all other H atoms were positioned geometrically with C-H distances of 0.93-0.97 Å, N-H 0.86 Å and were included in the refinement in the riding motion approximation with U iso = 1.5U eq (C) for methyl H and 1.2U eq for all other H atoms. Fig. 1. The structure and atom-numbering scheme for (I); displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radius.