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Org. Synth. 1971, 51, 20
DOI: 10.15227/orgsyn.051.0020
ALDEHYDES FROM AROMATIC NITRILES: 4-FORMYLBENZENESULFONAMIDE
[Benzenesulfonamide, 4-formyl-]
Submitted by T. van Es and B. Staskun1.
Checked by A. Brossi, L. A. Dolan, and A. Laurenzano.
1. Procedure
A 2-l., two-necked, round-bottomed flask fitted with a mechanical stirrer and a reflux condenser is charged with 40.0 g. (0.232 mole) of 4-cyanobenzenesulfonamide (Note 1), 600 ml. of 75% (v/v) formic acid, and 40 g. of Raney nickel alloy (Note 2). The stirred mixture is heated under reflux for 1 hour (Note 3). The mixture is filtered with suction through a Büchner funnel coated with a filter aid (Note 4), and the residue is washed with two 160-ml. portions of 95% ethanol. The combined filtrates are evaporated with a rotary evaporator (Note 5). The solid residue (Note 6) is dissolved in 400 ml. of boiling water and freed from a small amount of insoluble material by decantation through a plug of glass wool placed in a filter funnel. The filtrate is chilled in an ice bath, and the precipitate is collected by filtration with suction, washed with a small amount of cold water, and dried at 50° under vacuum, yielding about 32 g. of crude product, m.p. 112–114°.
The product is dissolved in 800 ml. of hot 95% ethanol, 15.5 g. of activated carbon (Note 7) is added, and the mixture is swirled periodically while it is allowed to cool for 1 hour. The activated carbon is removed by filtration with suction through a bed of filter aid (Note 4), the filter cake is washed with 50 ml. of 95% ethanol, and the combined filtrates are evaporated with a rotary evaporator. The residue is dissolved in 225 ml. of boiling water, and the hot solution is decanted through glass wool placed in a filter funnel. The filtrate is cooled to 0°, the product is collected by filtration with suction, washed with a small amount of cold water, and dried in a vacuum oven at 50°, yielding 25.6–28.0 g. (62.9–68.8%) of 4-formylbenzenesulfonamide, m.p. 117–118° (Note 8).
2. Notes
1. The checkers used 4-cyanobenzenesulfonamide purchased from Aldrich Chemical Company, Inc., m.p. 167–169°. The submitters prepared this material by diazotization of the corresponding amine,2 followed by cyanation.3 The product was crystallized from water, m.p. 152–154°.
2. The checkers used material purchased from Harshaw Chemical Company. The submitters used nickelaluminum alloy (50% Ni, 50% Al) supplied by British Drug Houses Ltd.
3. The reaction proceeds with some frothing; this is more appreciable and vigorous in mixtures containing a higher proportion of water, as when the reduction is conducted in 50% formic acid.4
4. Hyflo Supercel, a filter aid purchased from Johns-Manville Corporation, was used by the checkers.
5. This procedure is to be avoided with steam-volatile aldehydes (e.g., 4-chlorobenzaldehyde), in which case the reduction product is isolated by solvent extraction.4
6. The product is contaminated with nickel salts; its IR spectrum showed little, if any, unchanged nitrile.
7. Norite A, purchased from Matheson, Coleman and Bell, was used.
8. The melting point of 4-formylbenzenesulfonamide has been reported as 118–120°,4,5 122°,6 and 123–124°.7
3. Discussion
4-Formylbenzenesulfonamide has been prepared by chromic acid oxidation of p-toluenesulfonamide,5 the Sommelet reaction on 4-chloromethylbenzenesulfonamide,8 and by the Stephen reduction of 4-cyanobenzenesulfonamide.5 The present method provides a general procedure for the synthesis of substituted aromatic aldehydes as illustrated in Table I.
TABLE I
ALDEHYDES FROM AROMATIC NITRILES4

Nitrile

Aldehyde

Yield, %a


C6H5CN

C6H5CHO

97

4-ClC6H4CN

4-ClC6H4CHO

100

4-CH3OC6H4CN

4-CH3OC6H4CHO

93

2-C10H7CN

2-C10H7CHO

95


a Determined as the 2,4-dinitrophenylhydrazone derivative.

Some studies seeking preferred conditions for this reaction have been made. Optimum yields are obtained when the amount of water present is appreciable, and it was noted that the rate of hydrogen evolution increases with increasing water content. A 75% formic acid system appears to be generally preferred. Under the reaction conditions examined by the submitters, olefins, ketones, esters, amides, and acids are inert, but nitro compounds are reduced to the formamide derivative.
A related method for the synthesis of aldehydes from nitriles has also been studied.9 This method, which has been found to be extremely effective for the reduction of hindered nitriles to aldehydes, uses moist, preformed Raney nickel catalyst in formic acid. Compounds synthesized by this method are illustrated in Table II.
TABLE II
ALDEHYDES FROM NITRILES WITH RANEY NICKEL CATALYST IN FORMIC ACID9

Nitrile

Aldehyde

Yield, %a


C6H5CN

C6H5CHO

72

2-CH3C6H4CN

2-CH3C6H4CHO

65–75

2-ClC6H4CN

2-ClC6H4CHO

70–83

2-CH3OC6H4CN

2-CH3OC6H4CHO

80

2,6-(CH3O)2C6H3CN

2,6-(CH3O)2C6H3CHO

60–65

C6H5CH=CHCN

C6H5CH=CHCHO

64


a Determined as the 2,4-dinitrophenylhydrazone derivative.


References and Notes
  1. Department of Chemistry, University of the Witwatersrand, Johannesburg, South Africa.
  2. C. H. Andrewes, H. King and J. Walker, Proc. R. Soc. London, Ser. B, 133, 20 (1946).
  3. R. C. Iris, R. D. Leyva, and C. Ramirez, Rev. Inst. Salubr. Enferm. Trop. Mexico City, 7, 95 (1946) [Chem. Abstr. 41, 4117g (1947)].
  4. T. van Es and B. Staskun, J. Chem. Soc., 5775 (1965).
  5. H. Burtod P. F. Hu, J. Chem. Soc., 601 (1948).
  6. S. Koizuka and K. Ichiriki, Japan. Pat. 180,234 (1949) [Chem. Abstr., 46, 5085e (1952)].
  7. T. P. Sycheva and M. N. Shchukina, Sb. Statei Obshch. Khim., 1, 527 (1953) [Chem. Abstr., 49, 932c (1955)].
  8. S. J. Angyal, P. J. Morris, J. R. Tetaz, J. G. Wilson, J. Chem. Soc. 2141 (1950).
  9. B. Staskun and O. G. Backeberg, J. Chem. Soc., 5880 (1964).

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

Raney nickel alloy

ethanol (64-17-5)

hydrogen (1333-74-0)

formic acid (64-18-6)

aluminum (7429-90-5)

nickel,
Raney nickel (7440-02-0)

carbon,
activated carbon (7782-42-5)

chromic acid (7738-94-5)

4-Formylbenzenesulfonamide,
Benzenesulfonamide, 4-formyl- (3240-35-5)

4-cyanobenzenesulfonamide

4-chlorobenzaldehyde (104-88-1)

4-chloromethylbenzenesulfonamide

p-toluenesulfonamide (70-55-3)