Патент USA US3054807код для вставки
7 United States Patent 0 M C6 , 3,054,191 Patented Sept. 18, 1962 1 2 3,054,797 perature range may be employed. We have found it pref erable, for the majority of purposes, to utilize Raney nickel as the hydrogenation catalyst. As previously PROCESS FOR THE PREPARATION OF S-AMINOHEXAHYDROPYRIMIDINES Wilton 0. Bell, Monroe, La., and Albert E. Neckar, Terre Haute, Ind., assignors to Commercial Solvents Corpora tiou, New York, N.Y., a corporation of Maryland No Drawing. Filed Oct. 11, 1961, Ser. No. 144,301 5 Claims. (Cl. 260-2564) stated, the reaction can be effected at hydrogen pressures ranging in excess of 500 pounds. We have found it pref erable, however, to carry out the reaction at pressures not in excess of 1,000-4,200 pounds for at higher pres sures there is tendency to cleave the hexahydropyrim idine ring. Also, as previously stated, temperatures rang Our invention relates to the production of S-amino ing from about 25 to about 100° C. are suitable for our hexahydropyrimidines. More particularly it relates to an 10 reaction. However, we prefer to utilize temperatures of improved process for producing S-aminohexahydropyrim idines having the ‘following formula: CH2 / NHz from about 70 to about 100° C. Solvents which can be suitably utilized in the reduction procedure include the lower aliphatic alcohols such as methanol, ethanol, etc., 15 and the like. vIn order to achieve a product having optimum color characteristics and purity, it is preferable to cease hydro genation on completion of the reaction which is indicated by failure of additional hydrogen adsorption. After com pletion of the reaction, the 5-aminohexahydropyrimidines where R is lower alkyl and R1 is alkyl. S-aminohexahydropyrimidines can be prepared by we process described in US. Patent 2,3 87,043, issued to can be puri?ed by ?rst separating the hydrogenation cata lyst from the reaction mixture by ?ltration and then re moving the solvent by distillation. Murray Senkus. Brie?y this process consists of subject— The following examples are offered to illustrate our in ing a mixture of a S-nitrohexahyd-ropyrimidine, a nickel However, it is not intended that the invention hydrogenation catalyst and a solvent to liquid phase hy 25 ‘vention. be limited to the speci?c materials set forth; rather, it is drogcnation at pressures above 500 pounds and at tem peratures ranging from about 25 to about ‘100° C. and intended that all equivalents apparent to those skilled in the art be included in the scope of the invention as de fractionally distilling the resulting hydrogenation product scribed in this speci?cation and the attached claims. Example I To a hydrogenation apparatus containing 500 m1. of methanol and 10 grams of Raney nickel catalyst were to recover the S-aminohexahydropyrirnidine. S-aminohexahydropyrimidines produced by the above described process are generally of poor color and purity. Therefore, in order to obtain a product having acceptable color characteristics and sufficient purity, it is necessary to continuously added over a period of one hour, 240 grams employ not only expensive distillation equipment but to 35 of S-nitro-l,3—bis(2-ethylhexyl)-5-methy1hexahydropyrim use repeated distillation procedures. The need ‘for mul idine. During the one-hour period, the resulting mixture tiple distillations and the requirement of expensive and was hydrogenated at approximately 1,000 pounds per highly specialized equipment thus greatly increases the square inch utilizing room temperature as the initial tem cost of the ?nal product. perature and gradually increasing the temperature to We have now discovered an improved process whereby 40 about 70° C. At the end of the one-hour period, hydro S-aminohexahydropyrimidines having the following for genation was stopped. The reaction mixture was ?rst ?ltered to remove the catalyst and was then distilled at atmospheric pressure at a temperature of 70° C. to re move methanol. 197.5 grams of 5-amino-1,3-‘bis(2-ethyl mula: 45 hexyl) -5~methylhexahydropyrimidine were collected. The collected material had a color of Gardner 2. Example 11 allows a comparison of the color character istics of S-amino-l,3-bis(2-ethylhexyl)methylhexahydro pyrimidine prepared according to Example I by the proc wherein R is lower alkyl and R1 is alkyl having indus 50 ess of our invention with 5-amino~1,3-bis(2-ethylhexyl) trially acceptable color characteristics and degrees of S-methylhexahydropyrimidine prepared using the prior purity can be produced without the necessity of repeated and expensive puri?cation procedures. Thus, our new j1 process represents a signi?cant economic advancement in _,the production of S-aminohexahydropyrimidines. Our invention consists essentially of incrementally add ing the S-nitrohexahydropyrimidine to be reduced to a art method. A comparison of the results shows the effec tiveness of our process in producing a substantially color 55 less pure 5-amino~l,3-bis(Z-ethylhexyl)-5-methylhydro pyrimidine. Example II A mixture consisting of 240 grams of 5-nitro-1,3-bis mixture of methanol and hydrogenation catalyst and hy drogenating the mixture while continuously maintaining (Z-ethylhexyl)-5-methylhexahydropyrimidine, 500 ml. of Generally, in carrying out our invention, any hydro genation catalyst which is active within the aforesaid tem approximately 1,000 pounds per square inch using room temperature as the initial temperature. As the reduction methanol, and 10 ‘grams of Raney nickel catalyst was a temperature of from about 25 to about 100° C. and a 60 placed in a suitable hydrogenation apparatus and sealed. pressure in excess of 500 pounds. This mixture was then hydrogenated at a pressure of 1 3,054,797 a 3 4 . proceeded, however, the temperature was gradually in Now having described our invention, what we claim is: 1. In a process for the production of S-amino-hexa creased to approximately 80° C. Hydrogenation was continued for a period of about one hour at which time hydropyrimidines of the formula: adsorption of hydrogen had ceased. Upon cessation of hydrogenation the reaction mixture was withdrawn from the hydrogenation apparatus, the catalyst removed from the solution by ?ltration, and the solution was distilled at atmospheric pressure at 70° C. to remove methanol. 193 grams of 5-amino-1,3-bis(2-ethylhexyl)-5-methyl hexahydropyrimidine were collected. The material had a 0 l0 N?a \R wherein R is ‘lower alkyl and R1 is alkyl of improved color ‘by subjecting a S-nitrohexahydropyrimidine to hy Example III drogenation in the liquid phase in the presence of a hydro A portion of S-nitro-l,3-dibenzyl-S-methylhexahydro genation catalyst at temperatures ranging from about 25 pyrimidine was subjected to hydrogenation following the to about 100° C. and at pressures in excess of 500 pounds vprocedure of Example I to obtain 5-amino-1,3-dibenzyl 15 the improvement which comprises incrementally intro S-methylhexahydropyn'midine. The color characteristic ducing the S-nitrohexahydropyrimidine into the liquid of the material was similar to that shown in Example I. phase hydrogenation reaction. color of Gardner 8. Example IV 2. The process of claim 1 wherein the S-aminohexa A portion of S-nitro-1,3-diisopropylhexahydropyrim 20 ylhexahydropyrimidine. 'idine was subjected to hydrogenation following the pro cedure of Example I to obtain 5-amino-l,3-diisopropyl hexahydropyr-imidine. The color characteristic of the material was similar to that shown in Example I. Example V V A portion of vS-nitro-17,3,i-trimethylhexahydropyrim hydropyrimidine is 5-arnino-1,3-bis (2-ethylhexy1)-5-meth 3. The process of claim 1 wherein the S-aminohexa hydropyrimidine is 5-arnino—l,3-dibenzyl-5-methylhexahy dropyrimidine. 25 V 4. The process of claim 1 wherein the S-arninohexa hydropyrimidine is’ S-amino-1,3-diisopropylhexahydropy Iimidine. ‘idine was subjected to hydrogenation following the pro 5. The process of claim 1 wherein the hexahydropy cedure of Example I to obtain 5-amino-1,3,5-trimethyl 30 rimidine is 5-amino-1,3,S-trimethylhexahydropyrimidine. * hexahydropyrimidine. The color characteristic of the No references cited. material was similar to that shown in Example I.