Patent GB-838709-A (GB)
Title: Improvements in or relating to aminoalcohol-n-sulphonic acid compounds
IPC: C08B37/00
Filed: 1956-09-18
Abstract: The invention comprises aliphatic amino alcohol-N-sulphonic acids containing only one nitrogen atom and free of O-sulphate groups, and alkali metal or alkaline earth metal salts thereof and a process for the preparation of these compounds and of N-sulphonic acids and their alkali metal and alkali earth metal salts, other amino alcohols containing a primary or secondary amino group, without sulphating the hydroxyl groups, which comprises reacting the amino alcohol with a pyridine-sulphur trioxide complex in an aqueous alkaline medium of an alkali metal or alkaline earth metal hydroxide or carbonate at a pH between about 7 and about 11.5, yielding the desired sulpho compounds in salt form from which the free sulpho acids may be obtained. Reaction is generally effected at about 0-50 DEG  C.  The resulting amino-alcohol-N-sulphonic acid salts may be isolated by concentrating to remove the pyridine, adding ethanol, treating the resulting oil layer with acetone to form a solid layer, heating the solid with ethanol, extracting with aqueous alcohol and fractionally precipitating the desired salt by addition of acetone.  The amino alcohol N-sulpho compounds may alternatively be recovered, after removal of piperidine, by adding NaCl and ethanol, removing precipitated inorganic compounds by filtration and then adding acetone to precipitate the desired amino alcohol N-sulphonate.  The free amino alcohol N-sulphonic acids may be obtained by treating aqueous solutions of their metal salts with a strong acid cation exchange resin.  Numerous amino alcohols are specified including in addition to those named below, such aliphatic amino alcohols as monoethanolamine and its N-butyl derivative, various amino butanols, 2-amino-1,3-butane diol and tris (hydroxy methyl) amino methane and aromatic amino alcohols such as b -amino-a -phenyl ethanol and a -phenyl-b -methyl amino ethanol.  The N-sulphonation products of amino primary alcohols may be converted into amino carboxylic acids by oxidation of the carbinol group to -COOH and hydrolysis of the N-sulpho group to give the -NH2 group.  The N-sulphonation products of the amino sec. alcohols may be reacted with ethylene oxide under alkaline conditions to give ionic detergents.  The N-sulphonation products of amino tert.-alcohols can be acylated with a long-chain fatty acid chloride in the presence of pyridine to yield detergents. In examples: (1) a pyridine/SO3 complex and aqueous NaOH are added gradually to an aqueous solution of 3-amino propanol at a pH of about 11.3 yielding sodium 3-amino propanol N-sulphonate from which are prepared (a) the free acid by treating an aqueous solution of the salt with a cationexchange resin; and (b) b -amino propionic acid hydrochloride by reacting an aqueous Na2CO3 solution of the salt with sodium permanganate, filtering and refluxing the solution with hydrochloric acid; (2) p  diethanolamine is reacted as in (1) at a pH of 9-10 yielding sodium diethanolamine N-sulphonate from which are prepared the free sulpho acid and imino diacetic acid hydrochloride by the methods of 1(a) and 1(b); (3) the sodium salt of D,L-serine is reacted as in (1) yielding sodium D,L-serine N-sulphonate from which are likewise obtained the free sulpho acid and glycine hydrochloride. Specification 746,870 is referred to.ALSO:The invention comprises neo-hyaluronic acid-N-sulphonic acid and its alkali metal and alkaline earth metal salts and a method of the preparation of these compounds and corresponding compounds of other amino polysaccharides wherein primary or secondary amino groups are present in which method the parent amino polysaccharide is N-sulphated without sulphation of the hydroxy groups by reaction with a pyridine-SO3 complex in an aqueous alkaline medium of an alkali metal or alkaline earth metal hydroxide or carbonate at a pH between about 7 and about 11.5, yielding the metal salts of the desired N-sulphonic acids from which the free acids may be obtained, for example, by treating aqueous solution of their salts with a strong acid cation exchange resin. The amino polysaccharides specified are chitosan, neochondroitin sulphate and neohyaluronic acid, the latter being obtained by deacetylation of chondroitin sulphate and hyaluronic acid.  The sulphation is generally effected at about 0-50 DEG  C.  The resulting N-sulphonic acid salts may be isolated by concentrating the reaction mixture to remove the pyridine, adding ethanol to the residue, treating the resulting oil layer with acetone, extracting the solid product with aqueous alcohol and fractionally precipitating the desired salt from the extract with acetone; alternatively, after removal of pyridine, the product is dialysed to remove inorganic sulphates, a salt such as NaCl is added and the desired product precipitated by means of alcohol or acetone. The N-sulpho products may be converted into compounds useful as anticoagulants by reaction with a hydroxy-group sulphating agent such as chlorsulphonic acid in carbon tetrachloride or SO3 dissolved in sulphur dioxide whereby hydroxy groups in the polysaccharide N-sulphonate are sulphated.  In examples: (1) an aqueous suspension of a flocculent chitosan, obtained by dissolving chitosan in aqueous HCl and then precipitating it by gradual addition of aqueous NaOH, is stirred while adding a pyridine -SO3 complex portionwise, a pH of about 9-10 being maintained by means of aqueous NaOH and the product, sodium chitosan-N-sulphonate, is isolated by the dialysis method; the sodium salt is dissolved in water and treated with a cationexchanger and the free chitosan N-sulphonic acid recovered from the eluate; alternatively, the sodium chitosan N-sulphonate is suspended in liquid SO2 and O-sulphated with sulphur trioxide yielding sodium O-sulpho chitosan-N-sulphonate on working up by a method comprising the dialysis procedure above described; (2) following the procedure of (1), neo-hyaluronic acid is converted into sodium neohyaluronic acid N-sulphonate and the free N-sulphonic acid and into sodium O-sulpho neo-hyaluronic acid N-sulphonate; (3) neo-chondroitin sulphate is similarly converted into the corresponding neo-chondroitin sulphate N-sulphonic acid and its sodium salt and sodium O - sulpho - neochondroitin sulphate N - sulphonate. Specification 746,870 is referred to.