Patent GB-982940-A (GB)
Title: Improvements in or relating to urethanes and oxazolidine-diones and their thio analogues
IPC: C07D277/34
Filed: 1961-05-11
Abstract: Urethanes of formula <FORM:0982940/C2/1> where R is an alkyl radicle, X is O or S, R1 and R2 are the same or different and are each hydrogen, a straight or branched chain alkyl radicle, or an aryl radicle, or are connected in the form of a polymethylene ring, and Y is a substituted or unsubstituted alkyl, cycloalkyl, heterocyclic, aralkyl, or aryl radicle are made by treating in a liquid medium an amine of formula RNH2, with phosgene, in solution in a solvent which does not include a reactive hydrogen atom, and an ester of formula R1(R2)C(XH)COOR, at not more than 85 DEG  C., and at 50 DEG  to 60 DEG  C. for at least a part of the total reaction time, the ester being introduced so that at any instant the total molar amount of ester introduced into the liquid medium, from the beginning of the reaction, is at least equal to the quantity of the amine introduced from the beginning of the reaction, the amount of phosgene being not less than the minimum amount required to react with the amine. Preferably Y is an aryl radicle substituted with 1-3 halogen atoms or an alkyl, haloalkyl, alkoxy, nitro or carbalkoxy group. Preferably reaction temperatures of -10 DEG  to 85 DEG  C. are used, the amount of phosgene being 1.3 to 2.5 moles per mole of amine and the amount of ester being from 1.05 to 1.5 moles per mole of amine.  If the reaction is effected in two stages the first stage is preferably effected at - 10 DEG  to 20 DEG  C. and the second at 40 DEG  to 85 DEG  C., especially 45 DEG  to 70 DEG  C.  For a single stage reaction the temperature is preferably 40 DEG  to 85 DEG  C. especially 45 DEG  to 70 DEG  C.  Indicated solvents are aliphatic and cycloaliphatic hydrocarbons, e.g. heptane and cyclohexane, aromatic hydrocarbons, e.g. toluene, and their halogenated derivatives, e.g. chlorobenzene, ethers e.g. n-butyl ether, esters e.g. n-butyl acetate and ketones e.g. methyl isobutyl ketone. Derivatives of the above urethanes, 2,4-oxa- and thiazolidine-diones, of formula <FORM:0982940/C2/2> are made by degassing the reaction product obtained in the preparation of the urethanes, by heating, if necessary under vacuum, and after removing the solvent, if desired, e.g. by distillation, heating the reaction mixture in the presence of an alkaline catalyst.  The solvent is removed if it has a boiling-point lower than that of the urethane.  Cyclisation may occur instantaneously or require up to 24 hours and is preferably effected at 100-150 DEG  C.  The urethanes, and oxazolidine diones in which both R1 and R2 are substituents, may be used as plant growth regulants, see Division A5. Representative of compounds obtained in the examples are 3(31-chlorophenyl)-5-phenyl, 3-benzyl - 5 - methyl -, 3(21 - methoxy - 51 - chlorophenyl) - 5 - methyl - and 3 - butyl - 5 - methyl-, 3(31 - chlorophenyl) -, 3(31 - trifluoromethylphenyl) - 5 - ethyl -, 3(31 - nitrophenyl) - 5 -methyl -, 3(p - methoxybenzyl) - 3 - phenyl - 5,51 - pentamethylene- and 3(21-pyridyl)-5-methyl-2,4-oxazolidine diones, and 3(31-chlorophenyl) - 2,4 - thiazolidine - dione, and their intermediate acyclic compounds. Triethylamine and N-methyl morpholine are the cyclization catalysts used.ALSO:Urethanes of formula <FORM:0982940/A5-A6/1> where R is an alkyl radicle, X is O or S, R1 and R2 are the same or different and are each hydrogen, a straight or branched chain alkyl radicle, or an aryl radicle, or are connected in the form of a polymethylene ring, and Y is a substituted or unsubstituted alkyl, cycloalkyl, heterocyclic, aralkyl or aryl radicle, and their cyclic derivatives of formula <FORM:0982940/A5-A6/2> where R1 and R2 are as above, but not hydrogen, and X is O, are used in plant growth regulating compositions.  For the preparation of the regulants see Division C2.  Preferred are oxazolidone-diones where neither R1 nor R2 is hydrogen.  In examples, in which certain plants are treated with aqueous dispersions of oxazolidone-diones, Y is chosen from C6H5 and m- and p-C1C6H4, R1 is CH3 and R2CH3 or C2H5 or R1 and R2 may be combined to give a cyclo-penta-or tetra-methylene ring.