(E)-N-Butyl-3-(3,4-dihydroxyphenyl)acrylamide hemihydrate

In the title compound, C13H17NO3·0.5H2O, a new caffeic acid amide derivative, the solvent water molecule lies on a twofold axis and the terminal ethyl group appears disordered with occupancy factors of 0.525 (6) and 0.475 (6). The benzene ring makes an angle of 17.3 (2)° with the C=C—C—O linker. The presence of an ethylenic spacer in the caffeic acid amide molecule allows the formation of a conjugated system, strongly stabilized through π-electron delocalization. The C=C double bond in the linker is trans, similar to those previously reported in caffeic esters. The crystal is stabilized by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds. The molecules of the caffeic acid amide form a supermolecular planar structure through O—H⋯O hydrogen bonds between a hydroxy group of one caffeic acid molecule and a carbonyl O atom of another. These planes interact via C—H⋯O, O—H⋯O and N—H⋯O hydrogen bonds to form a three-dimensional network.

In the title compound, C 13 H 17 NO 3 Á0.5H 2 O, a new caffeic acid amide derivative, the solvent water molecule lies on a twofold axis and the terminal ethyl group appears disordered with occupancy factors of 0.525 (6) and 0.475 (6). The benzene ring makes an angle of 17.3 (2) with the C C-C-O linker. The presence of an ethylenic spacer in the caffeic acid amide molecule allows the formation of a conjugated system, strongly stabilized through -electron delocalization. The C C double bond in the linker is trans, similar to those previously reported in caffeic esters. The crystal is stabilized by O-HÁ Á ÁO, N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds. The molecules of the caffeic acid amide form a supermolecular planar structure through O-HÁ Á ÁO hydrogen bonds between a hydroxy group of one caffeic acid molecule and a carbonyl O atom of another. These planes interact via C-HÁ Á ÁO, O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds to form a threedimensional network.

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Acta Cryst.  (Altuğ et al., 2008). Phenolic acid amides, is a large class of organic compounds formed by the condensation reaction of aromatic acid and amine (Bylov et al., 1999). The -CO-NH-backbone makes amides have the pharmacological functionality such as anti-proliferative, antiviral, antimalarial, general anesthetics and antimicrobials. Therefore, more and more phenolic acid amides have already been researched purposively and developed as potential anti-proliferative, antiviral, antimalarial, and antimicrobials drugs in recent years (Son & Lewis, 2002;Menezes et al., 2001;Lee et al., 2005). So in this paper, we synthesized and report on the structure of a new caffeic acid amide derivative, (E)-N-butyl-3-(3,4-dihydroxyphenyl)acrylamide monohydrate.
In the title compound ( Fig. 1), all values of the geometric parameters are normal, the terminal C12-C13 group being disorderd with occupation factors of 0.525/0.475 (6) for both moieties. The benzene ring is planar within experimental observation (r.m.s. deviation: 0.005Å) and it makes an angle of 17.3 (2)° to the (C7-C8-C9-O3) linker. In the case of caffeic amide, the presence of an ethylenic spacer allows the formation of a conjugated system, strongly stabilized through π-electron delocalization. The C7═C8 bond is a trans-double bond, the same as in caffeic esters reported before (Xia et al., 2008).

Experimental
To a stirred THF solution (15 ml) of commercial caffeic acid (0.179 g, 1 mmol) was added DCC (1.5 mmol) in THF (5 ml) at 0°C. The reaction mixture was stirred for 2 h at 0°C and n-butylamine (0.088 g, 1.2 mmol) was added for reacting overnight at room temperature, and then the precipitated dicyclohexylurea was filtered and washed with tetrahydrofuran.
The combined filtrates were evaporated, the residue was extracted with EtOAc, and the extract was washed with 1 N NaHCO 3 , H 2 O, and 1 N HCl, dried over Na 2 SO 4 , and evaporated. The title compound was obtained by elution of the column with 25% petrole:EtOAc and recrystallized to give the pale yellow block crystal.

Refinement
All the H atoms were seen in a difference map but repositioned geometrically (

Figure 1
View of the molecular structure of (E)-N-butyl-3-(3,4-dihydroxyphenyl)acrylamide monohydrate with displacement ellipsoids at the 30% probability level. In open bonds, the minor part of the disordered tail.   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. The terminal C13 and methylene C12 have been treated disorderd.