| dc.description.abstract | this thesis is concerned with the studies in the synthesis of a monoterpenoid alkaloid, chaksine.
ethyl 2-n~butyl-4-bromoacetoacetate (11) was treated with sodium azide to give ethyl 2-n-butyl-4-azidoacetoacetate (12), catalytic hydrogenation
of (12) in presence of hydrochloric acid followed by the reaction of the hydrogenation product (13) with potassium cyanate afforded 4-(1'-
carbethoxypenty1)-2-imidazolone (14) or 4-(1'-carboxypentyl)-
2-imidazolone (15) depending on reaction condition.
4-(1'-carbethoxymethyl)-2-imidazolone (25) was also prepared starting from ethyl 4-bromoacetoacetate (23a) following the same series of reaction
as described for the compound (14). ethyl 2-[4'-methy1-5'-(2"-tetrahydropyranyloxy1)pentyl] acetoacetate (20) was prepared from the reaction of ethyl acetoacetate and 5-bromo-2-methyl-1-(2'-tetrahydropyranyloxyl)pentane (19). removal of the 3,4-
dihydropyran protecting group from (20) yielded ethyl
2-(4'-methyl—5'-hydroxypentyl)acetoacetate (21). the
compound (21) was also prepared directly by the
reaction of ethylacetoacetate with 5-bromo-2-methyl-
pentanol (18), the compound (21) was then subjected
to bromination to give (22a) followed by the treatment
of (22a) with sodium azide to yield ethyl 2-(4'-methyl-5'-hydroxypentyl)-4-azidoacetoacetate (22b) . | |
