Processes relating to the alkylation of pyrazoles
AssigneeSyngenta Crop Protection AG
InventorsLinhua Wang, Ritesh Bharat Sheth, Maren Fuerst
Life of this patent
Estimating the term…
Abstract
The present invention relates to processes for the preparation of a compound of formula (I) comprising reacting a compound of formula (IV) with a compound of formula III or (IIIA) in the presence of an acid; wherein R1 is C1-C4 haloalkyl; R2 is optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl; R3 is methyl or ethyl; R4 is hydrogen, optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl; and n is 0 or 1.
Claims13
A process for the preparation of a compound of formula I:
- wherein R1 is C1-C4 haloalkyl;
- R2 is optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl;
- and
- R3 is methyl or ethyl;
- comprising reacting a compound of formula IV:
- wherein R1, R2 and R3 are as defined for the compound of formula I;
- with a compound of formula III or IIIA:
- wherein n is 0 or 1;
- R3 is as defined for the compound of formula I;
- R4 is hydrogen, optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl;
- in the presence of an acid.
A process for the preparation of a compound of formula I:
- wherein R1 is C1-C4 haloalkyl;
- R2 is optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl;
- and
- R3 is methyl or ethyl;
- comprising reacting a compound of formula II:
- wherein R1 and R2 are as defined for the compound of formula I;
- with a compound of formula III or IIIA:
- wherein n is 0 or 1;
- R3 is as defined for the compound of formula I;
- R4 is hydrogen, optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl;
- in the presence of an acid.
A process for inter-converting a compound of formula IV and a compound of formula I according to Scheme I:
- wherein R1 is C1-C4 haloalkyl;
- R2 is optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl;
- and
- R3 is methyl or ethyl;
- using a compound of formula III or IIIA:
- wherein n is 0 or 1;
- R3 is as defined for the compound of formula I and IV;
- and
- R4 is hydrogen, optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl;
- and an acid as inter-conversion reagents.
Dependencies are inferred from the claim text.