The total synthesis of 3,7 dimethyl 2 tridecanyl acetate,the active component of the sex pheromone of diprion pini,was investigated in this paper.The two key synthins blocks,2 methyl octan 1 yl lithium and 3,4 dimethyl γ butyrolactone,were obtained from diethyl malonate and 2,3 epoxybutane.2 Methyl octan 1 yl lithium reacted with 3,4 dimethyl γ butyrolactone to yield the ketoalcohol and then followed by Huang Minlong reduction to afford 3,7 dimethyl 2 tridecanol,acylated with acetic anhydide to give 3,7 dimethyl 2 tridecanyl acetate.
As a kind of substrate competition type 5α reductase inhibitor,finasteride is a promising medicine used in the clinical treatment of benign prostatic hyperplasia (BPH).In this paper,a new route for the synthesis of finasteride from pregnenolone was proposed.Thus,pregnenolone was converted to finasteride in 10 steps,i.e.,ammoniumation,methoxylation,Oppenauer oxidation,hydrolyzation,cleavage of Δ 4 double bond by oxidation,ring closure by ammonia,hydrogenation of Δ 5 double bond,esterification with methanol,dehydrogenation of 1,2 position in A ring and Bodroux reaction.In this route,expensive reagent 2,2 dipyridyl disulfide commonly used in previous literature was avoided.All of the desired compounds were characterized by MS or/and NMR.The overall yield of finasteride was 13.67% based on pregnenolone.
The key intermediates of the sex pheromone of the pine sawfly 2-methyl-octanol and 2-methyl- decanol were synthesized from n-octanol and n-decanol sucessively via the oxidation with pyridinium chlorochromate(PCC), Mannich reaction, catalytic transferhydrogenation over Pd/C and reduction by LiAlH 4 in the total yield of 23.4% and 38.8%, respectively. Using acetic acid as solvent of pH=7, the yield of α-hexyl-acrolein in Mannich reaction was up to 70.1% in the optimized condition. 2-Methyl-dodecanol was similarly synthesized with the same procedure in the total yield of 48.2%.
