Hydrochloric Acid → 2-Nitroso-1-naphthol

温度

20 °C

48 g of 1-nitroso-2-naphthol are suspended in a mixture of 300 ml of water and 60 ml of 5n NaOH, then another 240 ml of 5n NaOh are added. While stirring well hot water vapor is passed through the solution until the temperature reaches 35° C. Subsequently 120 g of freshly prepared sodium dithionite is added with the temperature rapidly rising to 60° C. The solution assumes an amber-colored tint. After 15 minutes, the solution is rapidly cooled to under 20° C. by adding 200 g of ice and 100 ml of concentrated hydrochloric acid. The white, flaky precipitation is filtered by vacuum and suspended in a mixture of 500 ml of water and 50 ml concentrated hydrochloric acid. Overheated water vapor is passed into this mixture with such a volume flow that the temperature reaches 90° C. within 10 min. At this temperature is stirred another hour while reducing the vapor flow. The still hot solution is filtered with the aubergine-colored precipitation remaining. Upon cooling the filtrate, a light, flaky precipitation falls out which is sucked away, scavenged with diluted hydrochloric acid and then with ether and dried. Yielded were 45 g of 1-amino-2-naphthol-hydrochloride. The amino-hydroxy aromatic compounds were employed in all the transformations into this acidic form, because the free bases with the exception of 5-amino-6-quinoline proved to be very unstable.

1. customreaches 35° C
2. customrapidly rising to 60° C
3. customThe white, flaky precipitation
4. filtrationis filtered by vacuum
5. additionsuspended in a mixture of 500 ml of water and 50 ml concentrated hydrochloric acid
6. waitreaches 90° C. within 10 min
7. filtrationThe still hot solution is filtered with the aubergine-colored precipitation
8. temperatureUpon cooling the filtrate
9. customa light, flaky precipitation
10. dry with materialwith ether and dried
11. customYielded

ORDレコード

ord-186c76bf8c6b4f44980252642b2ccb85

出典データセット

uspto-grants-1998_09

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US05801243