Patent GB-722087-A (GB)
Title: Alpha-hydroxy-gamma-mercaptobutyramides, a process of preparing the same and feedingstuffs containing the same
Filed: 1951-10-24
Abstract: Alpha - hydroxy - gamma - mercapto - butyramide of formula <FORM:0722087/IV (b)/1> in which each R is H or CH3 and R1 is H or an alkyl group of 1-12 C atoms is made by treating a cyanohydrin of formula <FORM:0722087/IV (b)/2> in a solution containing sufficient mineral acid to dissolve the cyanohydrin at temperatures below 75 DEG C. and allowing the cyanohydrin to remain in the solution at below 75 DEG  C. until it is converted to the amide.  The cyanohydrin may be made from a corresponding aldehyde of formula <FORM:0722087/IV (b)/3> on treatment with hydrogen cyanide or an equivalent cyanide.  The aldehydes are made by reacting hydrogen sulphide, sodium hydrogen sulphide or an alkyl mercaptan of 1-12 C atoms, e.g. methyl and dodecyl mercaptans, with acrolein, tiglaldehyde or crotonaldehyde. Beta-methylmercapt propionaldehyde is the preferred starting aldehyde.  Reaction of the aldehyde with the cyanide may be effected by treating the aldehyde with an alkali metal bisulphite or meta-bisulphite to form the addition product which is reacted in aqueous solution with an alkali metal cyanide, preferably in equimolar proportions at about 20-40 DEG  C.  The cyanohydrin may also be obtained by reacting the aldehyde with anhydrous hydrogen cyanide in the presence of amines such as pyridine.  Preferably equimolar proportions or an excess of hydrogen cyanide are used with temperatures of about 20-45 DEG  C.  Sulphuric acid is the preferred mineral acid, phosphoric acid also being specified. Treatment with acid is preferred at about 20-40 DEG  C. and with a solution of about 50-85 per cent of specified acids.  Mol. ratios of acid to cyanhydrin of 1.5 : 1 or higher may be used.  The higher concentrations of acid are used at the lower temperatures.  Preferably the acid is added to the cyanhydrin in small portions over a period of about 30-180 minutes.  Although aqueous hydrolysis is preferred inert organic solvents, e.g. carbon tetrachloride may be present.  In examples: (1) beta-methylmercapto propionaldehyde is treated with sodium metabisulphite and the mixture with sodium cyanide at 25-35 DEG  C. to yield alpha-hydroxy-gamma-methylmercapto butyronitrile which after isolation is treated with aqueous sulphuric acid at about 35 DEG  C. to yield the corresponding amide; and (2) beta-methylmercapto propionaldehyde is treated with liquid hydrogen cyanide in the presence of pyridine at 30-40 DEG  C. and the nitrile so obtained treated with aqueous sulphuric acid at 30-35 DEG  C. to yield the required amide.  Alpha - hydroxy - gamma - methylmercapto-butyronitrile may be added to animal or poultry feeds, c.f. Group I.ALSO:Poultry or animal feeds deficient in methionine promote the growth of poultry and four-legged non-ruminants e.g. swine, cats and dogs, when fortified with a -hydroxy-g -methylmercapto-butyramide.  Amounts of about 0.1-0.5 per cent. by weight of the feed are specified for poultry. Example (3) illustrates the rapid growth of chicks fed on a basal diet containing protein, carbohydrates, vitamins and minerals and 0.2 per cent. of a -hydroxy-g -methylmercapto-butyramide.  For the preparation of the amide (see Group IV (b)).