Preparation and use of 2-substituted-5-oxo-3-pyrazolidinecarboxylates
View Patent ↗A method is disclosed for preparing a 2-substituted-5-oxo-3-pyrazolidinecarboxylate compound of Formula I. The method comprises contacting a succinic acid derivative of the formula R 1 OC(O)C(H)(X)C(R 2a )(R 2b )C(O)Y (i.e. Formula II)wherein X and Y are leaving groups and L, R 1 , R 2a and R 2b are as defined in the disclosure, with a substituted hydrazine of the formula LNHNH 2 (i.e. Formula III) in the presence of a suitable acid scavenger and solvent. Also disclosed is the preparation of compounds of Formula IV wherein X 1 , R 6 , R 7 , R 8a , R 8b , R 9 , and n are as defined in the disclosure. Also disclosed is a composition comprising on a weight basis about 20 to 99% of the compound of Formula II wherein R 1 , R 2a , R 2b , R 3 , R 4 and R 5 are as defined in the disclosure; X is Cl, Br or I; and Y is F, Cl, Br or I; provided that when R 2a and R 2b are each H, and X and Y are each Cl then R 1 is other than benzyl and when R 2a and R 2b are each phenyl, and X and Y are each Cl, then R 1 is other than methyl or ethyl. Also disclosed is a crystalline composition comprising at least about 90% by weight of the compound of the formula R 1 OC(O)C(H)(X)C(R 2a )(R 2b )CO 2 H (i.e. Formula VI) wherein R 2a and R 2b are H, X is Br and R 1 is methyl.
1. A method for preparing a 2-substituted-5-oxo-3-pyrazolidinecarboxylate compound of Formula I
wherein
L is H, optionally substituted aryl, optionally substituted tertiary alkyl, —C(O)R 3 , —S(O) 2 R 3 or —P(O)(R 3 ) 2 ;
R 1 is an optionally substituted carbon moiety;
R 2a is H, OR 4 or an optionally substituted carbon moiety;
R 2b is H or an optionally substituted carbon moiety;
each R 3 is independently OR 5 , N(R 5 ) 2 or an optionally substituted carbon moiety;
R 4 is an optionally substituted carbon moiety; and
each R 5 is selected from optionally substituted carbon moieties; comprising: contacting a succinic acid derivative of Formula II
wherein
X is a leaving group; and
Y is a leaving group; with a substituted hydrazine of Formula III
LNHNH 2 III
in the presence of a suitable acid scavenger and solvent.
2. The method of claim 1 wherein X is Cl, Br or I.
3. The method of claim 2 wherein X is Br.
4. The method of claim 1 wherein Y is Cl.
5. The method of claim 1 wherein R 1 is C 1 -C 4 alkyl.
6. The method of claim 1 wherein the compound of Formula I is of Formula Ia
the compound of Formula II is of Formula IIa
and the compound of Formula III is of Formula IIIa
wherein
each R 9 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;
Z is N or CR 10 ;
R 10 is H or R 9 ; and
n is an integer from 0 to 3.
7. The method of claim 6 wherein X is Br.
8. The method of claim 6 wherein Y is Cl.
9. The method of claim 6 wherein R 1 is CH 3 .
10. The method of claim 1 wherein methyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate is prepared by contacting methyl 2-bromo-4-chloro-4-oxobutanoate with (3-chloro-2-pyridin-2-yl)-hydrazine in the presence of sodium bicarbonate as the acid scavenger and acetonitrile as the solvent.
11. The method of claim 6 wherein the compound of Formula Ia is methyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate, the compound of Formula IIa is methyl 2-bromo-4-chloro-4-oxobutanoate and the compound of Formula IIIa is (3-chloro-2-pyridin-2-yl)-hydrazine.
12. The method of claim 11 wherein the acid scavenger is selected from the group consisting of sodium bicarbonate, sodium carbonate, sodium hydrogenphosphate and sodium phosphate.
13. The method of claim 12 wherein the solvent is selected from the group consisting of nitrile solvents.