Lead montelukast

The Cilag resolution of the pyridyl amino acid is described in Org. Process Res. Dev. 2001, 5, 23. For an informative comparison of different auxiliary and catalytic methods for the synthesis of a simple chiral carboxylic acid, see Org. Process Res. Dev. 2003, 7, 370. For a leading reference to the use of enzymes to reduce ketones, see the account of the Codexis work on montelukast in Org. Process Res. Dev. 2010, 14, 193. The spectacular synthesis of discodermolide by Novartis using a series of aldol reactions is described in Org. Process Res. Dev. 2004, 8, 92, 101 and 107. 

Vaccines and desensitization have been suspected to trigger or act as adjuvant factors in the development of CSS (110,111), and are thus considered contraindicated in patients with overt CSS. The possible responsibility of leukotriene-receptor antagonists (montelukast, zafirlukast, pranlukast) in the development of CSS has been debated (90,112), with no established causative role in epidemiological studies. However, some rather convincing case reports or personal observations lead us to consider that these agents should be avoided in asthmatic patients with eosinophilia and (or) extrapulmonary manifestations. Drug-induced eosinophilic vasculitis with pulmonary involvement has been occasionally reported. CSS has developed in an asthmatic patient a few months after starting omalizumab, an anti-IgE antibody (113). 

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