88198-24-7

Upstream product

• 78078-47-4 12-methoxyabieta-8,11,13-trien-2-one 
• 825638-58-2 2-(2-carboxy-1,1-dimethyl-ethyl)-4,7-dimethoxy-naphthalene-1-carboxylic acid methyl ester 
• 825638-66-2 2-(2-carboxy-1,1-dimethyl-ethyl)-4,7-dimethoxy-naphthalene-1-carboxylic acid 
• 825638-57-1 4,7-dimethoxy-2-(2-methoxycarbonyl-1,1-dimethyl-ethyl)-naphthalene-1-carboxylic acid methyl ester 
• 825638-60-6 6-methoxy-1,1-dimethyl-3,9-dioxo-1,3,4,9-tetrahydro-2H-phenanthrene-4a-carboxylic acid methyl ester 
• 119061-38-0 6β,20-epoxy-12-methoxyabieta-8,11,13-triene 
• 83109-84-6 (+/-)-2β,2O-epoxy-12-methoxyabieta-8,11,13-triene 
• 86531-95-5 decahydro-4a,8,8-trimethyl-4β-(tetrahydropyran-2-yloxy)naphthalen-1α-ol 
• 86531-95-5 decahydro-4a,8,8-trimethyl-4β-(tetrahydropyran-2-yloxy)naphthalen-1β-ol 
• 89837-42-3 C₂₀H₂₈O₄ 
• 89837-43-4 C₂₀H₃₀O₃ 
• 89837-44-5 6β,20-epoxyabieta-8,11,13-trien-12-ol 
• 119061-37-9 (1R,6R,7S)-5,5-Dimethyl-9-(3-oxo-butyl)-12-oxa-tricyclo[5.3.2.0^1,6]dodecan-10-one 
• 89837-34-3 decahydro-4a,8,8-trimethyl-4β-(tetrahydropyran-2-yloxy)naphthalen-1-one 

Downstream Products

• 113801-92-6 (4aS,10aR)-7-Isopropyl-6-methoxy-1,1-dimethyl-9-(toluene-4-sulfonyloxy)-1,3,4,9,10,10a-hexahydro-2H-phenanthrene-4a-carboxylic acid methyl ester 
• 67494-15-9 (+/-)-pisiferic acid 

Relevant academic research and scientific papers

Total Synthesis of (+/-)-Pisiferic Acid

A total synthesis of (+/-)-pisiferic acid (1) has been achieved by utilising the keto ether (22) which, in turn, was prepared from the alcohol (14).Subjection of the keto ether (22) to three sequential reactions (formylation, Michael addition with methyl vinyl ketone, and intramolecular aldol condensation) provided the tricyclic ether (27) whose conversion into the methoxyabietatriene (32) was accomplished in four steps (ethoxycarbonylation, Grignard reaction with methyl-lithium, acid-catalysed dehydration, and methoxylation).Reaction of the methoxyabietatriene (32) with zinc, zinc iodide, and acetic acid produced (+/-)-pisiferol (2) which was finally converted into (+/-)-pisiferic acid (1).The ketone (34) was converted into the abietatriene (41) following exactly the same procedure adopted for the transformation of the keto ether (22) into the abietatriene (32).Hydroboration-oxidation of (41) followed by oxidation with Jones reagent and reduction with lithium aluminium hydride followed by transannular oxidation gave the abietatriene (36).

Stereocontrolled total synthesis of (±)-pisiferol and (±)-pisiferal

The stereoselective total synthesis of (±)-pisiferol (1) and (±)-pisiferal (2) has been successfully accomplished using the trans-octahydrophenanthrene derivative 20 as a key intermediate. Intramolecular cyclisation of the diazoketone 15 followed by catalytic hydrogenation provided, stereoselectively, the keto-ester 17 which was converted into the acetate 20 through the intermediates 18 and 19.

SYNTHESIS OF (+/-)-2β,2O-EPOXY-12-METHOXYABIETA-8,11,13-TRIENE

The synthesis of the titled compound (1) and its conversion to pisiferic acid (2) are described.

Total Synthesis of (+/-)-Pisiferic Acid, Methyl (+/-)-Pisiferate, and (+/-)-Pisiferol

Acid catalyzed cyclization of 4-(3-isopropyl-4-methoxyphenethyl)-3,5,5-trimethyl-2-cyclohexen-1-one afforded 12-methoxyabieta-8,11,13-trien-2-one and its cis-isomer.Both compounds were further converted into 12-methoxyabieta-8,11,13-trien-2β-ol, which was treated with lead tetraacetate in the presence of iodine to yield 2β,20-epoxy-12-methoxyabieta-8,11,13-triene.Ether cleavage of the 2β,20-epoxy compound with acetyl p-toluenesulfonate, followed by catalytic hydrogenation, afforded 20-acetoxy-12-methoxyabieta-8,11,13-triene (23).This was then converted into methyl 12-methoxyabieta-8,11,13-trien-20-oate (27) via methyl 12-methoxy-7-oxoabieta-8,11,13-trien-20-oate.Demethylation of 27 with AlBr3-EtSH gave pisiferic acid, but with AlCl3EtSH 27 was partially demethylated to give methyl pisiferate.The acetate 23 was also converted into pisiferol by demethylation and reduction