| abstract |
Prodn. of optically active 3-demethylmevalonic acid derivs. (I) and their lactones (II) comprises (I) protecting primary OH gp. in diol-ester (VI) then condensing the rpduct, or its alkoxides, with tert. butyl acetate (or equiv.) to give keto-ester (VIII); (2) reducing this to 1,3-diol and converting this to protected deriv. (X); deprotecting terminal OH to give (III), the converting this to olefin deriv. (XI). This is hydrolysed to (I; Y = CH = CH; R1 = 1-8C alkyl), which can be hydrogenated to (I; Y = CH2CH2), and opt. free acids are converted conventionally to salt or lactone. ( Y = -CH=CH- or -CH2CH2-; R = gp. (i) or (ii) Z = CH or N; R3, R4 and R5 = H; upto 6C hydrocarbyl (opt. substd); 3-7C cyclic hydrocarbyl, satd. or with up to 2 unsaturations; or (all opt. substd. phenyl, furyl, thienyl or pyridyl; A-B = CH-CH or C=C; R6 and R7 = opt. unsatd. upto 20C alkyl (opt. substd.); 3-7C cycloalkyl; phenyl, thiophene, furan or naphthalene residue (all opt. substd.) or pyridyl (opt. substd. R9 = 1-8C alkyl; R8 = up to 8C opt. unsatd. alkyl, benzyl Iopt. ring substd. or phenyl, thiophene, furan or naphthalene residue (all opt. substd. R1 = H, metal cation or 1-8C alkyl; but is alkyl in all steps to (XI); R2 = protecting gp.; M = 1,3-diol protecting gp.. The aldehydes (XII) are new: M1 = CMe2, (iii) (iv), (v) or (vi). |