Reaktion #69041

Reaktionsgleichung

HCl

2-Amino-4,5-dichlorobenzoic acid

urea

NaOH

→

solid

Ausbeute 96.3%

6,7-dichloroquinazolin-2,4(1H,3H)-dione

Ausbeute 96.3%

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   FiltrationThe formed precipitate was filtered off
2. 2
   Waschenwashed with water
3. 3
   Sonstigeto yield a solid cake that
4. 4
   TemperaturThe suspension was heated
5. 5
   workup.WAITto boil for 5 minutes
6. 6
   Temperaturcooled to r.t
7. 7
   Filtrationthe quinazoline-dione was filtered off
8. 8
   WaschenAfter washing with a mixture of water and methanol the product
9. 9
   Sonstigewas dried in vacuo

Vorschrift

2-Amino-4,5-dichlorobenzoic acid (920 mg) and urea (2.75 g) were stirred at 160° C. After 6 hours the mixture was cooled to 100° C. and an equivalent volume of water was added while stirring was continued for 5 minutes. The formed precipitate was filtered off and washed with water to yield a solid cake that was suspended in a solution of 0.5 N NaOH in water. The suspension was heated to boil for 5 minutes and then cooled to r.t. The pH was adjusted to about 2 with HCl and the quinazoline-dione was filtered off. After washing with a mixture of water and methanol the product was dried in vacuo to yield 994 mg (94%) of a solid. 1H-NMR (DMSO-δ6) δ (ppm) 7.89 (s, 1H), 7.33 (s, 1H).

Quelle