US 9,808,457 B2
CGRP receptor antagonists
John Andrew Christopher, Welwyn Garden City (GB); Miles Stuart Congreve, Welwyn Garden City (GB); Sarah Joanne Bucknell, Welwyn Garden City (GB); Francesca Deflorian, Welwyn Garden City (GB); Mark Pickworth, Welwyn Garden City (GB); and Jonathan Stephen Mason, Welwyn Garden City (GB)
Assigned to Heptares Therapeutics Limited, Hertfordshire (GB)
Filed by Heptares Therapeutics Limited, Welwyn Garden City, Hertfordshire (GB)
Filed on Oct. 28, 2016, as Appl. No. 15/336,866.
Claims priority of application No. 1519196.8 (GB), filed on Oct. 30, 2015.
Prior Publication US 2017/0121348 A1, May 4, 2017
Int. Cl. A61K 31/496 (2006.01); C07D 241/14 (2006.01); C07D 498/20 (2006.01); C07D 471/04 (2006.01); C07D 401/14 (2006.01)
CPC A61K 31/496 (2013.01) [C07D 241/14 (2013.01); C07D 401/14 (2013.01); C07D 471/04 (2013.01); C07D 498/20 (2013.01)] 17 Claims
1. A compound of formula (I)

OG Complex Work Unit Drawing
or a salt thereof or an optical isomer thereof, wherein R1 is H or Q-(C1-C6)alkyl;
where Q is a bond, C(O) or C(O)O and where the (C1-C6)alkyl can be optionally substituted by N(C1-C3alkyl)2 or CO2H;
R2 is H or forms a spirocyclic heterocyclic ring with R3;
R3 forms a spirocyclic heterocyclic ring with R2 or is a heterocyclic ring if R2 is H; and
R4 is an optionally substituted aryl group which may be monocyclic or fused to a further ring.