Sodium hydroxide,
water,
hydroxylamine hydrochloride,
carbon dioxide,
ether

To a solution of sodium hydroxide (14 g; 0.33 mol) in water (40 cm³) was added benzaldehyde ( 21 g; 0.2 mol), followed by hydroxylamine hydrochloride (15 g; 0.22 mol) portionwise, with vigourous stirring. On cooling, and leaving to stand overnight, a crystalline mass formed. Water was added until this dissolved (about 150 cm³) and CO₂ gas was passed through. This was simply achieved by attaching a conical flask of solid CO₂ to a bubbler via the solution. The mixture went white, and an oil formed. The mixture was extracted with ether (4 x 75 cm³), dried and concentrated, and distilled under reduced pressure. Product obtained as a colourless liquid; reported to be a solid, mp 35 ^oC. Obtained exclusively as syn-isomer (see Pejkovic-Tadic et al. Helv. Chim. Acta, 1965, 48, 1157.) Yield 20.17 g; 93%

The liquid is pure, and worked well in further reactions. Scratching and trituration failed to get crystalline product. The bubbling of CO₂ through the aqueous mixture is presumably just a mild acidification, (forming carbonic acid) to effect the separation of the oil from the aqueous layer. Other arylaldoximes were prepared by similar methods, however the solvents the reactions were performed in, and other aspects of the procedures, were slightly different, and will be described on other synthetic pages (see Page 146 for one example). This reaction was performed only once.

¹H nmr (300 MHz; CDCl₃), 7.35-7.5 (3H, m), 7.55-7.65 (2H, m), 8.20 (1H, s), 8.55 (1H, bs)

A. J. McCarroll and J. C. Walton, J. Chem. Soc., Perkin Trans. 2, 2001, 1868.

B. S. Furniss, A. J. Hannaford, P. W. G. Smith and A. R. Tatchell, "Vogel's Textbook of Organic Chemistry, 5th Edition," Longman, Harlow, 1989.