4-(((4-Methoxyphenyl)amino)methyl)- N , N -dimethylaniline and 2-Methoxy-5-((phenylamino)methyl)phenol

: Molecular structures of 4-(((4-methoxyphenyl)amino)methyl)- N , N -dimethylaniline and 2-methoxy-5-((phenylamino)methyl)phenol synthesized via Schiff bases reduction route are reported. The compounds consist of asymmetric units of C 16 H 20 N 2 O ( 1 ) and C 14 H 15 NO 2 ( 2 ) in orthorhombic and monoclinic crystal systems, respectively. Compound 1 consist of intermolecular C11—H11 ··· N2 hydrogen bonding with C11 ··· N21 = 3.463(4) Å. The hydroxyl group in 2 is also involved in intermolecular O2—H2 ··· O2 and O2—H2 ··· O21 hydrogen bonding with O2 ··· O11 = 2.8885(15) Å and O1 ··· O21 = 2.9277(5) Å. The molecular structures of the compounds are stabilized by secondary intermolecular interactions of C1—H1B ··· O11 and C5—H ··· (C41, C51, C61, C71) for 1 and H ··· C, C—H ··· O and N—H ··· C for 2 . The reported compounds are important starting material for the synthesis of many compounds such as azo dyes and dithiocarbamate.


Synthesis of the Compounds
The compounds were synthesized by condensation of the primary amines with the corresponding aldehydes in methanol and sequential reduction of the resulting Schiff bases with sodium borohydride in methanol and dichloromethane at room temperature (Scheme 1).

Materials and Methods
All solvents and chemical reagents such as p-anisidine, aniline, 4-(dimethylamino)benzaldehyde, 3-hydroxy-4-methoxybenzaldehyde were obtained from Sigma Aldrich and used as obtained without further purification. The 1 H and 13 C NMR spectra were recorded on a Bruker Avance III 400 MHz spectrometer. The proton and carbon shifts are quoted in ppm relative to the solvent signals. FTIR spectra were recorded in the region 4000 to 650 cm −1 using a Cary 630 FTIR spectrometer (Agilent Technologies). Single mass analysis was carried out using the Waters Micromass LCT Premier TOF-MS. The spectra are presented in supplementary Figures S1-S8. Single crystal X-ray crystallography of the compounds were recorded on a Bruker APEX-II CCD diffractometer.

Synthesis of 4-(((4-methoxyphenyl)amino)methyl)-N,N-dimethylaniline (1)
P-anisidine (1.1084 g, 0.009 mol) dissolved in 20 mL methanol was placed in a two neck flask and 4-(dimethylamino)benzaldehyde (1.4919 g, 0.01 mol) was added, the resulting mixture was refluxed at 80 °C for 8 h. The solvent was then removed under vacuum to give a yellow oily product. The yellow oily product was dissolved in 1:1 dichloromethane:methanol (20 mL) and added in portion to sodium borohydride (0.7566 g, 0.02 mol) at room temperature and stirred for 20 h. The solvent was removed under vacuum and the product extracted with dichloromethane and washed with water. The whitish solid product obtained was recrystallized in methanol to give single crystals suitable for X-ray crystallography. Yield

Materials and Methods
All solvents and chemical reagents such as p-anisidine, aniline, 4-(dimethylamino) benzaldehyde, 3-hydroxy-4-methoxybenzaldehyde were obtained from Sigma Aldrich and used as obtained without further purification. The 1 H and 13 C NMR spectra were recorded on a Bruker (Billerica, MA, USA) Avance III 400 MHz spectrometer. The proton and carbon shifts are quoted in ppm relative to the solvent signals. FTIR spectra were recorded in the region 4000 to 650 cm −1 using a Cary 630 FTIR spectrometer (Agilent Technologies, Santa Clara, CA, USA). Single mass analysis was carried out using the Waters Micromass LCT Premier TOF-MS (Waters, Milford, MA, USA). The spectra are presented in Supplementary Figures S1-S8. Single crystal X-ray crystallography of the compounds were recorded on a Bruker (Billerica, MA, USA) APEX-II CCD diffractometer.

Synthesis of 4-(((4-Methoxyphenyl)amino)methyl)-N,N-dimethylaniline (1)
P-anisidine (1.1084 g, 0.009 mol) dissolved in 20 mL methanol was placed in a two neck flask and 4-(dimethylamino)benzaldehyde (1.4919 g, 0.01 mol) was added, the resulting mixture was refluxed at 80 • C for 8 h. The solvent was then removed under vacuum to give a yellow oily product. The yellow oily product was dissolved in 1:1 dichloromethane:methanol (20 mL) and added in portion to sodium borohydride (0.7566 g, 0.02 mol) at room temperature and stirred for 20 h. The solvent was removed under vacuum and the product extracted with dichloromethane and washed with water. The whitish solid product obtained was recrystallized in methanol to give single crystals suitable for X-ray crystallography. Yield, 1.7995, 78%, 1

Synthesis of 2-Methoxy-5-((phenylamino)methyl)phenol (2)
Aniline (1.46 mL, 0.016 mol) dissolved in 20 mL methanol was placed in a two-neck flask and 3-hydroxy-4-methoxybenzaldehyde (2.7387 g, 0.018 mol) was added, the resulting mixture was refluxed at 80 • C for 8 h. The solvent was then removed under vacuum to give a yellow oily product. This was dissolved in 1:1 dichloromethane:methanol (20 mL), and sodium borohydride (1.3619 g, 0.036 mol) were added in portion at room temperature and stirred for 20 h. The solvent was removed under vacuum and after which the product was extracted with dichloromethane and washed severally with water. The solvent was removed to give a whitish solid product that was recrystallized in methanol to obtain single crystals suitable for X-ray crystallography. Yield, 2.9347,

Single Crystal X-ray Crystallography
Single colorless block and plank-shaped crystals of 1 and 2 were obtained from slow evaporation of methanolic solution of the compounds. Suitable crystals (0.78 × 0.34 × 0.32) mm 3 and (0.38 × 0.21 × 0.14) mm 3 of 1 and 2 were selected and mounted on a MITIGEN holder in paratone oil on a Bruker APEX-II CCD diffractometer [22] and data were collected using Olex2 [23] with the crystal temperature kept at T = 100(2) K. The structures were solved in a space group Pca2 1 and P2 1 for 1 and 2, respectively, with ShelXS-2013 [24] structure solution program, using the direct solution method. The model was refined with version 2016/6 of ShelXL [25] using least squares minimization.

Conclusions
The molecular structures of the compounds 2-methoxy-5-((phenylamino) methyl) phenol (1) and 4-(((4-methoxyphenyl)amino)methyl)-N,N-dimethylaniline (2) are reported. The compounds crystallized as monomeric entity of in an orthorhombic and monoclinic crystal system for 1 and 2, respectively. Each compound is held together in the unit cell by the combination of both intramolecular covalent and intermolecular secondary interactions. The compounds are useful starting materials for the synthesis of many important organic compounds.
Supplementary Materials: The following are available online, including copies of 1 H, 13 C NMR, FTIR, and TOF mass-spectra for the compounds 1 and 2 ( Figure S1-Figure S8). Figure S1