Benzamide crystal

Fig. 2 Intermolecular interactions in benzamide crystal showing the carboxamide dimers and hydrogen-bonded chain. (From Ref. l)...

Figure 3.38 Disruption of crystal growth process by the incorporation of tailor-made additive benzoic acid at the interface of a growing benzamide crystal. (After Wright 1987.)...

Fig. 9 Hydrogen bonding, (a) Benzamide crystal containing Nile red in the 102 growth sectors. [100] is vertical. View along [010]. (b) Proposed structure of Nile red on the (102) face of benramide consistent with the linear dichroism and energy of the solvatochromic dye. View this art in color at WWW. dekker. com.)...

Benzamide crystallizes from ethanol in the form of 001 platelike crystals elongated along the -axis. The structure consists of rihhons of H-honded cyclic pairs interlinked by NHLO bonds along the fc-axis. What happens if benzoic acid is then added as an additive The replacement of the -NHj group by an -OH group retards the incorporation of other benzamide molecules, with increased growth in the a-direc-tion. Scheme 6.13 illustrates these effects schematically for benzamide growing in the presence of benzoic acid. 

Carry out this preparation in precisely the same way as the above preparation of oxamide, using 2 ml. (2-4 g.) of benzoyl chloride instead of the ethyl oxalate, and observing the same precautions. Considerably more heat is generated in this reaction therefore hold the cork very securely in position during the shaking. After vigorous shaking for 15 minutes, no trace of oily benzoyl chloride remains. Filter off the fine flakes of benzamide, wash with cold water, and then recrystallise from hot water yield, 1-5 g. Colourless crystals, m.p. 130°. 

Place I g. of benzamide and 15 ml. of 10% aqueous sodium hydroxide solution in a 100 ml. conical flask fitted with a reflux water-condenser, and boil the mixture gently for 30 minutes, during which period ammonia is freely evolved. Now cool the solution in ice-water, and add concentrated hydrochloric acid until the mixture is strongly acid. Benzoic acid immediately separates. Allow the mixture to stand in the ice-water for a few minutes, and then filter off the benzoic add at the pump, wash with cold water, and drain. Recrystallise from hot water. The benzoic acid is obtained as colourless crystals, m.p. 121°, almost insoluble in cold water yield, o 8 g. (almost theoretical). Confirm the identity of the benzoic acid by the tests given on p. 347. 

A mixture of 2-chloro-A-(2-hydroxyl-l-methyl-2-phenylethyl)benzamide (44) (9.5g, 24.9 mmol) and P2O5 in o-chlorobenzene (1,50 mL) was refluxed overnight. Upon completion, the reaction was cooled to room temperature and then chilled to 0 °C. To the crude reaction mixture, 300 mL of water was cautiously added. The resulting dark solution was washed with toluene (2 x 50 mL). The aqueous layer was cooled to 0 °C and 50% NaOH added to final pH of 11. The resulting mixture was extracted with toluene (4 x 50 mL). The toluene fractions were combined, dried, filtered and concentrated in vacuo. The residue was crystallized from benzene to afford l-(2-chlorophenyl)-3-methylisoquinoline (45) as a white solid (6.68g, 80%). M.P. = 107-108 °C H NMR (CDCI3) S 8.45 (s, IH), 8.11 (d, IH), 7.85 (dt, IH), 7.41-7.68 (bm, 6H), 2.51 (s, 3H). 

B. N-Nitroso-N-(2-phenylethyl)benzamide. A solution of 10.4 g. (0.046 mole) of the crude N-(2-phenylethyl)benzamide, 7.36 g. (0.09 mole) of anhydrous sodium acetate, and-50 ml. of glacial acetic acid is placed in a 250-ml. Erlenmeyer flask equipped with a drying tube, and the mixture is cooled to the crystallization point of the acetic acid (Note 1). A solution of dinitrogen tetroxide (Notes 2, 3) in glacial acetic acid (85 ml. of a solution approximately 1M in N2O4) is then added with stirring. The reaction mixture is allowed to warm to about 15° (15 minutes), and then it is poured into a mixture of ice and water. The yellow solid nitroso derivative is dissolved in 75 ml. of carbon tetrachloride, and this solution is washed with 5% sodium bicarbonate, water, and dried. The solution is used directly in the next step. 

Polyazo dyes, 9 363—361 Polybenzamide, 15 109-110 Poly(p-benzamide) (PBA), 10 212 19 714 crystal lattice parameters of, 19 728t laboratory synthesis of, 19 719 Polybenzimidazole (PBI), asbestos substitute, 3 3141 Polybenzimidazole (PBI) fibers,... 

Benzamide (43,51) crystallizes from ethanol in space group Pljc. The main features of the crystal structure (52) (Figure 5) are similar to those found in cinnamide. Hydrogen-bonded cyclic dimers are interlinked along the 5.0-A b axis to form ribbons. The ribbons are stacked along the 5.6-A a axis, in an... 

Figure 6. Photographs of crystals of benzamide (a) pure (b)-(d) grown in the presence of increasing amounts (from bottorrf to top) of (b) benzoic acid (c) o-toluamid, (d) p-toluamid. The crystals shown in this photograph (and all those following) varied in size from about 0.1 to 5 mm.

This reduction in crystal symmetry is conveniently illustrated in the systems cinnamide, benzamide, or, in general, any amide RCONH2 packing in a ribbon motif comprising centrosymmetric hydrogen-bonded dimers interlinked by translation (Scheme 16). 

S,3R)-3-amino-2-octaml ce >98% (after crystallization of the benzamide from hexane/ethyl acetate). 

Reaction of secondary benzamides with Me2Zn affords the corresponding methylzinc benzamides (equation 23) . X-ray crystal structure determinations of these compounds revealed complex irregular aggregates in which all nitrogen and oxygen atoms are involved in bonding to zinc. 

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