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US 2003/0166936 A1Published application
Process for preparing a quinolone-carboxylic acid
AssigneeLynchem Co., Ltd.
InventorsYuncai Wang, Rongye Chen, Haijun Nan
Life of this patent
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Abstract
The present invention provides a process for preparing quinolonecarboxylic acid derivatives having the formula (I): 1 wherein R1 is H, halogen, or amino; R2 is halogen; R3 is H, halogen, C1-4 alkoxyl, or CN; R4 is selected from the group consisting of C3-6cycloalkyl, C1-4alkyl, C1-4alkoxyC1-4alkyl, and C1-4alkylaminoC1-4alkyl. The invention also provides new acetophenones having the formula (II) that are intermediates for preparing the compound of the formula (I).
Claims9
A process for preparing quinolonecarboxylic acid derivatives having the formula (I):
- 9
- wherein R1 is H, halogen, or amino,
- R2 is halogen,
- R3 is H, halogen, C1-4 alkoxyl, or CN,
- R4 is selected from the group consisting of C3-6cycloalkyl, C1-4alkyl, C1-4alkoxyC1-4alkyl, and C1-4alkylaminoC1-4alkyl,
- comprising the steps of:
- i) reacting a compound of the formula (II)
- 10
- wherein R1, R2 and R3 are defined as above, and R7 is a halogen, with an alkyl carbonate to obtain a compound of the formula (III),
- 11
- wherein R8 is methyl or ethyl;
- ii) reacting a compound of the formula (III) successively with an alkyl orthoformate and a compound of the formula (IV) R4NH2 to obtain a compound of the formula (V),
- 12
- iii) cyclizing the compound of the formula (V) in the presence of a base to form a compound of the formula (VI);
- and
- 13
- iv) hydrolyzing the compound of the formula (VI) to obtain a compound of the formula (I).
14 more elements
A compound of the formula (II):
- 14
- wherein, R1 is H, or Cl;
- R2 is Cl;
- R3 is F, C1-4 alkoxyl, or CN;
- and R7 is Cl.
2 more elements
Dependencies are inferred from the claim text.