Method for preparing 3-halo-4,5-dihydro-1
View Patent ↗This invention relates to a method for preparing a 3-halo-4,5-dihydro-1H-pyrazole compound of Formula I comprising contacting with HX 1 a different 4,5-dihydro-1H-pyrazole compound of Formula II wherein X 1 is halogen and L, R, k and X 2 are as defined in the disclosure. This invention also discloses preparation of compounds of Formula III wherein X 1 , R 3 , R 6 , R 7 , R 8a , R 8b and n are as defined in the disclosure.
1. A compound of Formula IIa
wherein
each R 3 is independently C 1 -C 4 alkyl, C 2 -C 4 alkenyl, C 2 -C 4 alkynyl, C 3 -C 6 cycloalkyl, C 1 -C 4 haloalkyl, C 2 -C 4 haloalkenyl, C 2 -C 4 haloalkynyl, C 3 -C 6 halocycloalkyl, halogen, CN, NO 2 , C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, C 1 -C 4 alkylamino, C 2 -C 8 dialkylamino, C 3 -C 6 cycloalkylamino, (C 1 -C 4 alkyl)(C 3 -C 6 cycloalkyl)amino, C 2 -C 4 alkylcarbonyl, C 2 -C 6 alkoxycarbonyl, C 2 -C 6 alkylaminocarbonyl, C 3 -C 8 dialkylaminocarbonyl or C 3 -C 6 trialkylsilyl;
R 4 is H or C 1 -C 4 alkyl;
X 2 is OS(O) m R 1 ;
m is 1 or 2;
R 1 is selected from C 1 -C 2 alkyl, phenyl and 4-methylphenyl;
Z is N or CR 5 ;
R 1 is H or R 3 ; and
n is an integer from 1 to 3.
2. A compound of claim 1 wherein R 4 is C 1 -C 4 alkyl.
3. A compound of claim 2 wherein Z is N, n is 1, and R 3 is Cl or Br and is at the 3-position.
4. A compound of claim 3 wherein m is 2, and R 1 is phenyl or 4-methylphenyl.
5. A compound of claim 4 wherein R 4 is ethyl, R 3 is C 1 and R 1 is phenyl.
6. A compound of claim 4 wherein R 4 is ethyl, R 3 is C 1 and R 1 is 4-methylphenyl.
7. A method of preparing a compound of Formula Ia
wherein each R 3 is independently C 1 -C 4 alkyl, C 2 -C 4 alkenyl, C 2 -C 4 alkynyl, C 3 -C 6 cycloalkyl, C 1 -C 4 haloalkyl, C 2 -C 4 haloalkenyl, C 2 -C 4 haloalkynyl, C 3 -C 6 halocycloalkyl, halogen, CN, NO 2 , C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy, C 1 -C 4 alkylthio, C 1 -C 4 alkylsulfinyl, C 1 -C 4 alkylsulfonyl, C 1 -C 4 alkylamino, C 2 -C 8 dialkylamino, C 3 -C 6 cycloalkylamino, (C 1 -C 4 alkyl)(C 3 -C 6 cycloalkyl)amino, C 2 -C 4 alkylcarbonyl, C 2 -C 6 alkoxycarbonyl, C 2 -C 6 alkylaminocarbonyl, C 3 -C 8 dialkylaminocarbonyl or C 3 -C 6 trialkylsilyl;
R 4 is H or C 1 -C 4 alkyl;
X 1 is halogen;
Z is N or CR 5 ;
R 1 is H or R 3 ; and
n is an integer from 1 to 3, comprising:
contacting a compound of Formula IIa
wherein X 2 is OS(O) m R 1 ;
m is 1 or 2; and
R 1 is selected from C 1 -C 2 alkyl, phenyl and 4-methylphenyl, with a compound of formula HX 1 in the presence of a suitable solvent.
8. The method of claim 7 wherein R 4 is C 1 -C 4 alkyl.
9. The method of claim 8 wherein Z is N, n is 1, and R 3 is Cl or Br and is at the 3-position.
10. The method of claim 8 wherein X 1 is Br, m is 2, and R 1 is phenyl or 4-methylphenyl.