73804-45-2

Upstream product

• 85636-50-6 1-(trimethylsiloxy)-1-methoxy-1,3-butadiene 
• 124287-44-1 trans-methyl (7-bromo-3,4-dihydro-5,8-dioxo-1-methyl-1H-2-benzopyran-3-yl)acetate 
• 78340-70-2 methyl cis-9-hydroxy-1-methyl-5,10-dioxo-3,4,5,10-tetrahydro-1H-naphtho<2,3-c>pyran-3-ylacetate 
• 78340-69-9 trans-methyl <9-methoxy-1-methyl-5,10-dioxo-3,4,5,10-tetrahydro-1H-naphtho<2,3-c>pyran-3-yl>acetate 
• 78340-68-8 cis-methyl <9-methoxy-1-methyl-5,10-dioxo-3,4,5,10-tetrahydro-1H-naphtho<2,3-c>pyran-3-yl>acetate 
• 121638-14-0 3,3a,5,11b-Tetrahydro-5-hydroxy-7-methoxy-5-methyl-2H-furo<3,2-b>naphtho<2,3-d>pyran-2,6,11-trione 
• 3843-55-8 4,8-dimethoxy-1-naphthol 
• 73705-44-9 4,8-dimethoxy-1-naphthalenol acetate 
• 81418-42-0 3-acetyl-5-methoxy-1,4-naphthoquinone 
• 81418-41-9 1-(1-hydroxy-4,8-dimethoxynaphthalen-2-yl)ethanone 
• 344563-74-2 cis-methyl <9-methoxy-1-methyl5,10-dioxo-3,4,5,10-tetrahydro-1H-naphtho<2,3-c>pyran-3-yl>acetate 
• 82654-02-2 (E)-methyl-4-(3-acetyl-4-hydroxy-5-methoxy-1-oxo-1,2-dihydronaphth-2-yl)-2-butenoate 
• 82654-03-3 trans-methyl <5-<(tert-butyldimethylsilyl)oxy>-10-hydroxy-9-methoxy-1-methyl-3,4-dihydro-1H-naphtho<2,3-c>pyran-3-yl>acetate 
• 82654-04-4 cis-methyl <5-<(tert-butyldimethylsilyl)oxy>-10-hydroxy-9-methoxy-1-methyl-3,4-dihydro-1H-naphtho<2,3-c>pyran-3-yl>acetate 

Relevant academic research and scientific papers

NEW SYNTHETIC APPROACH TO PYRANONAPHTHOQUINONE ANTIBIOTICS, (+/-)-NANAOMYCIN A AND (+/-)-DEOXYFRENOLICIN

The new total synthesis of pyranonaphthoquinone antibiotics, (+/-)-nanaomycin A (1) and (+/-)-deoxyfrenolicin (2), is discussed.The key step in the reaction sequence is Lewis acid mediated Michael addition of acylnaphthoquinone (5) with methyl 2-(dimethylphenylsilyl)-3-butenoate (7).

A Short Synthesis of Deoxyfrenolicin

Oxidative rearrangement of furonaphthofuran 8 using CAN provided an efficient route to the hemiacetal 9 which has a three-ring system in common with that in the natural products frenolicin A 1, frenolicin B 2 and deoxyfrenolicin 3.Attempted reduction of the hemiacetal 9 to the cis-lactone 11 using triethylsilane and trifluoroacetic acid was unsuccessful, however, hydrogenation of the hemiacetal 9 not only effected reduction of the hemiacetal group to a cyclic ether but also hydrogenolysis of the γ-lactone to the ring-opened carboxylic acid which was conveniently characterized as its methyl ester 13.Deprotection of the methyl ether 13 to the naphthol 15 using boron tribromide also affected cis-trans epimerisation at C-1 thus completing a synthesis of deoxyfrenolicin 3 upon hydrolysis of the methyl ester to the carboxylic acid.

Allylation of 2-Alkanoyl 1,4-Quinones with Allylsilanes and Allylstannanes. Efficient Synthesis of Pyranonaphthoquinone Antibiotics

Total syntheses of pyranonaphthoquinone antibiotics eleutherin, isoeleutherin, nanaomycin A, and deoxyfrenolicin are described.The crucial step in the route is a regioselective allylation of alkanoyl quinones with allylsilanes and allylstannanes.The allyl

Pyranonaphthoquinone Antibiotics. Part 2. Syntheses of (+/-)-Nanaomycin A and (+/-)-Eleutherins

Two routes for the synthesis of (+/-)-nanaomycin A (1) starting with 2-bromo-8-methoxy-1,4-naphtoquinone (2) are described.The benzindanone (3) prepared from (2) in three steps was treated with methylmagnesium iodide and then with hydrochloric acid to afford the benzindene (8).Lemieux-Johnson oxidation of (8) gave the ketoaldehyde (9), which was converted into the conjugated ester (10) by reaction with methoxycarbonylmethylenetriphenylphosphorane.Reductive cyclisation of (10) with sodium borohydride afforded a ca. 1:1.9 mixture of the cis-naphthopyran (11) and its trans-isomer (12).Oxidative demethylation of (11) and (12) with cerium(IV) followed by treatment with aluminium chloride yielded the corresponding quinones (15) and (16).Ester hydrolysis of (16) formed (+/-)-nanaomycin A (1).Reductive methylation of the 2-allyl derivative of (2) afforded the bromonaphthalene (18), which was treated with butyl-lithium followed by acetaldehyde to give the naphthylcarbinol (19).The lactol (20) obtained by Lemieux-Johnson oxidation of (19) was treated with trimethyl phosphonoacetate-sodium hydride to yield a ca. 2.1:1 mixture of the naphthopyrans (11) and (12).Cyclisation of (19) with mercury(II) acetate-sodium borohydride yielded a ca. 1:0.9 mixture of the cis-naphthopyran (21) and its trans-isomer (22), which were oxidatively demethylated to give (+/-)-eleutherin (4) and (+/-)-isoeleutherin (5) respectively.