Reaction #1375804

Reaction equation

intermediate 4-a

(+)-6-[(4-chlorophenyl)hydrazinomethyl]-1-methyl-1H-benzotriazole monohydrochloride

methanimidamide monoacetate

→

(+)-6-[(4-chloro-phenyl)-(1H-1,2,4-triazol-1 -yl) methyl]-1-methyl-1H-benzotriazole

Yield 131.8%

Solvents

methanol

Conditions

Workup

1. 1
   Temperatureat reflux temperature
2. 2
   Otherthe reaction mixture crystallized
3. 3
   workup.ADDITIONthere were added 30 ml of water
4. 4
   workup.STIRRINGAfter stirring for 1 hour the precipitate
5. 5
   Filtrationwas filtered off
6. 6
   Washwashed with water
7. 7
   Otherdried in vacuo at 50° C
8. 8
   workup.ADDITIONThe product was diluted with 11.8 ml of 2-propanol
9. 9
   workup.ADDITIONthe whole was treated with active charcoal for 15 min.
10. 10
    Temperatureat reflux temperature
11. 11
    FiltrationThe charcoal was filtered off while hot and
12. 12
    Washwashed with 2-propanol
13. 13
    OtherThe product was crystallized
14. 14
    Filtrationfiltered off
15. 15
    Otherdried in vacuo at 50° C.

Procedure

A mixture of 5 g of intermediate 4-a, 4.8 g of methanimidamide monoacetate and 15 ml of methanol was stirred for 1.5 hours at reflux temperature. After cooling to room temperature, the reaction mixture crystallized and there were added 30 ml of water. After stirring for 1 hour the precipitate was filtered off, washed with water and dried in vacuo at 50° C. The product was diluted with 11.8 ml of 2-propanol and the whole was treated with active charcoal for 15 min. at reflux temperature. The charcoal was filtered off while hot and washed with 2-propanol. The product was crystallized, filtered off and dried in vacuo at 50° C., yielding 3.3 g (66.0%) of (+)-6-[(4-chloro-phenyl)-(1H-1,2,4-triazol-1 -yl) methyl]-1-methyl-1H-benzotriazole (comp. 1-a); mp. 130°-135° C.; [α]D20 =+8.0° (conc.=10% in CH3OH); enantiomeric excess: 98.4%.

Source