Benzenamine, N,3-dimethyl- → N1,3-dimethylbenzene-1,4-diamine

A mixture of 12.1 g N-methyl-m-toluidine (I) 14.5 g conc. HCl and 40 g of ice were stirred while 7 g NaNO2 were added over a period of 5 minutes. The mixture was cooled externally and small portions of ice were added when needed to keep the temperature below 10°C. The mixture was allowed to stand at 0°C for 1 hour after the addition was complete and the oily top layer formed was separated. The lower aqueous layer was then extracted twice with 10 ml portions of benzene and the combined organic layers were distilled under reduced pressure. The material which boiled at 132°-138°C/8mm Hg was collected and dissolved in ethanol. Dry HCl gas was passed through this solution which heated up and deposited a precipitate of N,2-dimethyl-4-nitrosaniline (III) as the hydrochloride salt. The 16 g of product were suspended in isopropanol and reduced over Pt/C on a Parr hydrogenator. The reduction mixture was filtered and the catalyst was extracted with water. The combined filtrates were evaporated to dryness to yield 8 g of the product N,3-dimethyl-p-phenylenediamine hydrochloride.

1. additionwere added over a period of 5 minutes
2. temperatureThe mixture was cooled externally
3. additionsmall portions of ice were added when
4. customthe temperature below 10°C
5. additionafter the addition
6. customthe oily top layer formed
7. customwas separated
8. extractionThe lower aqueous layer was then extracted twice with 10 ml portions of benzene
9. distillationthe combined organic layers were distilled under reduced pressure
10. customThe material which boiled at 132°-138°C/8mm Hg was collected
11. dissolutiondissolved in ethanol
12. temperatureheated up
13. filtrationThe reduction mixture was filtered
14. extractionthe catalyst was extracted with water
15. customThe combined filtrates were evaporated to dryness

ORD record

ord-65230b959d474ef08140f26eb9f1b041

Source dataset

uspto-grants-1976_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US03970423