An efficient synthesis of enantiopure SDZ 267–489 via a resolution/racemization method

A new synthesis of (R)-3-methyl-5-phenyl-5H-thiazolo[2,3-b]quinazoline 1, a serum HDL cholesterol raising agent, is described utilizing a resolution of the racemic compound with D-tartaric acid. The undesired S-enantiomer was recycled using either a photochemical or thermal electrocyclic ring opening/closing reaction making the synthesis economical. (C) 1996 Elsevier Science Ltd