Patent GB-756422-A (GB)
Title: Esters of urethanes of glycols and the manufacture thereof
IPC: C07D295/205
Filed: 1951-09-10
Abstract: The invention comprises polycondensed esters containing chain linkages of formula <FORM:0756422/IV(a)/1> where R1 is H or an aromatic or aliphatic radicle, R is an aliphatic radicle of at least 2 carbon atoms and R3 is a divalent residue of a dicarboxylic acid. They are made by condensing one mol. of an ester of formula H(R1)NCOOROOOCR3COOROOCN(R1)H which is made by treating a diacid with a glycol monourethane having at least one N-hydrogen atom (see Group IV (b)), with one mol. of the chloride or anhydride of the acid.  If R1 is H the use of excess acid reagent will lead to products in which R1 is an acyl residue.  In an illustration, one mol. of the neutral fumarate of glycol monourethane is treated with fumaryl chloride to give a product which is insoluble in water and boiling alcohol.ALSO:The invention comprises carboxylic esters of glycol monourethanes.  They are made by reacting carboxylic acids or their anhydrides or chlorides with monourethanes of glycols which may be substituted on the nitrogen atom.  In the presence of excess acid reagents the urethanes may also be acylated. Preferably acid chlorides are used.  Solvents may be present during the reaction. The products may be neutral esters of monoacids which may be acylated at the nitrogen atom or acid or neutral esters of polyacids or polycondensed esters containing chain linkages of formula <FORM:0756422/IV(a)/1> where R1 is H or a monovalent aromatic or aliphatic radicle, R is a divalent aliphatic radicle of a glycol having at least 2 carbon atoms and R3 is a hydrocarbon residue of a dicarboxylic acid.  Neutral esters of monoacids are made by reacting equimolar quantities of the appropriate reagents at room or elevated temperatures and their acylated derivatives are obtained when 2 mol. proportions of acid reagent are reacted with 1 mol. proportion of urethane, the acylation of mono-N-substituted urethanes being effected only at high temperatures when decomposition of the product is liable to occur.  Acid esters are obtained when a polyvalent acid reagent is reacted so that fewer mols. of urethane are present than there are acid groups available.  An azeotropic method is employed when a diacid is used as a reagent.  Temperatures used should not exceed 110-115 DEG  C. When an acid chloride is used the reaction is effected in two stages, a monoacid chloride being obtained in the first stage which is hydrolysed in the second.  In the first stage, however, polycondensed compounds may be formed when the urethane has a free N-hydrogen atom and in the second stage substantial saponification of the ester may occur.  The acid esters may be converted into their salts.  Neutral esters of polyacids may be made in a single stage reaction by reacting appropriate quantities of reagents or in a two-stage reaction when an anhydride is used the acid ester first obtained at below 110 DEG  to 115 DEG  C. being converted to the neutral ester by heating at 120-150 DEG  C., water being removed by vacuum or azeotropic distillation.  Acylated polycondensed esters are made by condensing one mol. of a neutral ester of a diacid and a urethane containing at least one free hydrogen atom on the N atom with one mol. of the chloride or anhydride of the acid.  In examples, neutral esters of mono acids are prepared from combinations of the following urethanes and acid reagents: piperidyl-, N-methyl-, -ethyl-, and -propyl-, N,N-dimethyl- and diethyl-, N - cyclohexyl -, N - benzyl -, N,N - ethylene-di-, piperazine-di- and morpholino-urethanes of glycol, the urethanes of glycol and propylene glycol and the N-ethyl urethane of propylene glycol, acetyl, benzoyl and p-nitrobenzoyl chlorides and acetic anhydride, acylated derivatives are obtained by reacting glycol and propylene glycol with acetyl chloride, acid esters of the urethanes of glycol and propylene glycol and their N-ethyl derivatives, and the N,N-dibutyl-and piperidyl urethanes of glycol with certain of the following acid reagents, maleic acid and anhydride, phthalic and succinic anhydrides, neutral esters of polyacids are are made from the urethanes of glycol and propylene glycol and their N-ethyl derivatives and certain of the following acid chlorides and anhydrides, fumaryl chloride, adipyl and succinyl chlorides and anhydrides, and maleic and phthalic anhydrides, and a polycondensation product from fumaryl chloride and the neutral fumarate of glycol urethane is also prepared.  Specification 689,705 is referred to.