| CPC C07D 471/14 (2013.01) [C07D 401/14 (2013.01); C07B 2200/05 (2013.01)] | 6 Claims |
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1. A compound of formula (1), an optical isomer, a crystalline form, or a pharmaceutically acceptable salt thereof:
![]() in formula (1):
R1 is aryl, heteroaryl,
![]() or
![]() wherein the aryl and the heteroaryl is optionally substituted by 1-3 groups selecting from the group consisting of halogen, C1-C3 alkyl, C1-C3 alkoxyl, halogen substituted C1-C3 alkyl and halogen substituted C1-C3 alkoxyl;
R2 is H or methyl;
R3 is H or F;
W is
![]() wherein Ra is H, C1-C3 alkyl or C3-C6 cycloalkyl; and
L is CH2, CO, CD2, CH(Me), C(Me)2,
![]() or
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