Hydrochloric Acid → Drometrizole

o-Nitroaniline (0.5 mole) was diazotized in the usual manner with concentrated hydrochloric acid (200 ml.) and sodium nitrite (0.5 mole). The clear diazonium solution was added slowly to a cold solution (0°-5°) of p-cresol (0.5 mole) in 450 ml of 10% sodium hydroxide. The mixture was stirred for 1 hour and 2-nitro-2'-hydroxy-5'-methylazoaniline (A) was filtered out (60% yield). One-tenth mole of A was dissolved in 100 ml. of 2N NaOH. Zinc dust (30 g.) and sodium hydroxide (50 ml. of a 25% solution) were added slowly to the well-stirred solution to keep the temperature below 45° C. The mixture was then cooled to <30° C. and acidified with concentrated hydrochloric acid. After stirring for 2 hours, the precipitate was filtered and recrystallized from toluene (mp 122°-24°) to give o-[2H-benzotriazol-2-yl)-4-methylphenol] (B). A solution containing 9.0 g. (0.04 mole) of B and 4.0 6 gm. (0.02 mole) of isophthaloyl chloride in 200 ml. of pyridine was heated with stirring at 50°-60° for 15 hrs. The reaction mixture was poured into cold dilute hydrochloric acid and a solid precipitated. The solid was filtered, and air-dried to give 1 as a white solid (30%, mp. 115°-8°).

1. filtration2-nitro-2'-hydroxy-5'-methylazoaniline (A) was filtered out (60% yield)
2. dissolutionOne-tenth mole of A was dissolved in 100 ml
3. additionof a 25% solution) were added slowly to the well-stirred solution
4. customthe temperature below 45° C
5. temperatureThe mixture was then cooled to <30° C.
6. stirringAfter stirring for 2 hours
7. filtrationthe precipitate was filtered
8. customrecrystallized from toluene (mp 122°-24°)

ORDレコード

ord-022b72dfebd9428bab457bbc8c018235

出典データセット

uspto-grants-1978_12

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US04128559