Patent GB-751110-A (GB)
Title: Improvements in and relating to aryl amidopropane-diols
Filed: 1954-01-25
Abstract: As blowing agents for polymeric materials such as polystyrene may be employed compounds of the general formula <FORM:0751110/IV(a)/1> wherein R represents a hydrogen or halogen atom, or an alkyl or alkoxy group of not more than 6 carbon atoms.ALSO:The invention comprises compounds of the general formul  <FORM:0751110/IV(a)/1> and <FORM:0751110/IV(a)/2> (wherein R represents a hydrogen or halogen atom, or an alkyl or alkoxy group of not more than 6 carbon atoms), and the preparation thereof by reacting the corresponding sulphofluorides with a metal salt of hydrazoic acid or with hydrazine (advantageously in the form of its hydrate), and in the latter case, if desired, treating the product with nitrous acid (advantageously formed in situ).  Preferably the acyl radical is acetyl, chloroacetyl, bromoacetyl, dichloroacetyl or dibromoacetyl, and R represents hydrogen.  The products, of which those of the first formula are useful as drugs, disinfectants, corrosion inhibitors, blowing agents for polymeric materials, anti-halation agents in photography, and additions to electroplating baths, exist as structural (erythro and threo) and optical isomers.  The racemic threo form may be resolved by hydrolysis with a hydrohalic acid to the amine salt, reacting this (in the pressure of an equivalent amount of silver oxide or carbonate), or the amine liberated therefrom, with an optically active acid, separating the diastereoisomers by crystallization from a solvent, and then liberating the optically active amines by treatment with caustic alkali or a base exchange resin and reacylating the product (e.g. with an acid halide, preferably dichloroacetyl chloride, or acetic anhydride, in the presence of a weak base, e.g. sodium acetate). In examples: (1) dlthreo - 1 - (p - fluorosulphonylphenyl) - 2 - dichloroacetamido - 1 : 3 - propanediol is stirred with sodium azide in N : N-dimethylacetamide; (2) the same starting material is stirred with an aqueous solution of hydrazine hydrate, and the resulting hydrazinosulphonyl compound is dissolved in dilute hydrochloric and treated with sodium nitrite.  1 - (p - Fluorosulphonylphenyl) - 2 - amido - 1 : 3 - propanediols employed as starting materials are obtainable from compounds of the formula <FORM:0751110/IV(a)/3> by oxidation with potassium permanganate and magnesium nitrate, followed by halogenation, addition of hexamethylentetramine, treatment with sulphur dioxide and water, acidification, acylation, treatment with formaldehyde and a weak base, and reduction with sodium borohydride or by the Meerwein Ponndorff-Verley method, in accordance with U.S.A. Specification 2,680,134.ALSO:As corrosion inhibitors for acid solutions on metal may be employed compounds of the general formula <FORM:0751110/II/1> wherein R represents a hydrogen or halogen atom, or an alkyl or alkoxy group of not more than 6 carbon atoms.ALSO:As blowing agents for rubber may be employed compounds of the general formula:- <FORM:0751110/V/1> wherein R represents a hydrogen or halogen atom, or an alkyl or alkoxy group of not more than 6 carbon atoms.