178231-95-3

Upstream product

• 146176-81-0 (2S,3R,4S,5R)-5-Azido-2,3,4-tris-benzyloxy-cycloheptanone 
• 159639-25-5 (2S,3R,4S,5S) 5-azido-2,3,4-tris(benzyloxy) cyclohept-6,7-en-1-one 
• 248582-41-4 (2S,3R,4S,5R)-2,4-dibenzyloxy-5-benzyloxycarbonylamino-3-hydroxycyclohept-6-en-1-one 
• 73111-58-7 2,3,4-tri-O-benzyl-5,6-dideoxy-D-xylo-hex-5-enose 
• 141077-21-6 (3aR,5R,6R,7R,8S)-6,7,8-Tris-benzyloxy-3a,4,5,6,7,8-hexahydro-3H-cyclohepta[c]isoxazol-5-ol 
• 146236-96-6 (2R,3S,4R,5S) 5-azido-2,3,4-tris(benzyloxy) cycloheptane-1-one 
• 959409-98-4 (2S,3S,4R,5S)-5-(N-benzyloxycarbonyl)-amino-2,3,4-tris(benzyloxy)-cycloheptanone 
• 1379671-99-4 1-((4R,5S)-5-(((tert-butyldimethylsilyl)oxy)methyl)-2,2-dimethyl-1,3-dioxolan-4-yl)-4-nitrobutan-1-one 
• 1379672-00-0 1-((4R,5S)-5-(hydroxymethyl)-2,2-dimethyl-1,3-dioxolan-4-yl)-4-nitrobutan-1-one 
• 1379672-02-2 (3aR,7S,8S,8aS)-8-hydroxy-2,2-dimethyl-7-nitrotetrahydro-3aH-cyclohepta[d][1,3]dioxol-4(5H)-one 
• 1379672-04-4 tert-butyl ((3aS,4S,5S,8aR)-4-hydroxy-2,2-dimethyl-8-oxohexahydro-3aH-cyclohepta[d][1,3]dioxol-5-yl)carbamate 
• 146514-64-9 (2S,3R,4S,5S) 5-<(t-butyldimethylsilyl)oxy>-2,3,4-tris(benzyloxy) cyclohept-6,7-en-1-one 
• 159639-22-2 (1R,2S,3R,4S,5S) 5-mesyloxy-2,3,4-tris(benzyloxy) cyclohept-6,7-en-1-ol 
• 248582-40-3 (2S,3R,4S,5R)-2,4-dibenzyloxy-5-benzyloxycarbonylamino-3-<(t-butyldimethylsilyl)oxy>cyclohept-6-en-1-one 

Relevant academic research and scientific papers

Synthesis of nortropane alkaloid calystegine B2 from methyl α-D-xylopyranoside

A new synthetic route for formation of a central cycloheptanone intermediate leading to the nortropane alkaloid calystegine B2 is described. The approach installs the desired ketone functionality directly in a ring-closing metathesis step. The

Method for preparing calystegine and intermediate thereof

The invention relates to the field of the synthesis of natural products, and discloses a method for preparing calystegine and an intermediate thereof. The calystegine has a structure as shown in a formula I. The method comprises the following steps of, in the presence of a protecting agent, carrying out a protective reaction on a hydroxyl group in primary alcohol as shown in a formula II; enabling alkene as shown in a formula III to react with ozone; carrying out an ylide reaction on aldehyde as shown in a formula IV; carrying out a deprotection reaction on alkenyl iodine as shown in a formula V; enabling alcohol as shown in a formula VI to react with a first oxidizing agent; carrying out an NHK (Nozaki-Hiyama-Kishi) reaction on aldehyde as shown in a formula VII; enabling alcohol as shown in a formula VIII to react with a second oxidizing agent; carrying out a reducing reduction on an unsaturated ketone as shown in a formula IX. By using the method, the calystegine is efficiently synthesized with a succinct route through raw materials which are easily obtained and are further low-cost. Through the method, a new route is provided for the synthesis of calystegine-series compounds, and a firm foundation is provided for screening a compound with a biological activity and a medicinal value. The formula I is shown in the description.

Concise synthesis of calystegines B2 and B3: Via intramolecular Nozaki-Hiyama-Kishi reaction

The key step in the concise syntheses of calystegine B2 and its C-2 epimer calystegine B3 was the construction of cycloheptanone 8via an intramolecular Nozaki-Hiyama-Kishi (NHK) reaction of 9, an aldehyde containing a Z-vinyl iodide. Vinyl iodide 9 was obtained by the Stork olefination of aldehyde 10, derived from carbohydrate starting materials. Calystegines B2 (3) and B3 (4) were synthesized from d-xylose and l-arabinose derivatives respectively in 11 steps in excellent overall yields (27% and 19%).

Total synthesis of ent-calystegine B4 via nitro-Michael/aldol reaction

Optically active ent-calystegine B4 was prepared in 13 steps from commercially available chiral l-dimethyl tartrate. The synthesis was achieved by the Michael addition and the aldol reaction of nitromethane to form cycloheptanone in a stereoselective manner. Reduction of the nitro group in the presence of Boc2O accomplished an efficient conversion to amino cycloheptanone, which readily afforded the desired ent-calystegine B4.

First total synthesis of 3-Epi-calystegin B2

A straightforward chiral pool synthesis for a non-natural calystegin, 3-epi-B2, is described. Key steps of this synthesis include an ultrasound-assisted Zn-mediated tandem ring opening reaction followed by a Grubbs' catalyst-mediated ring closu

Total Synthesis of Calystegine B4

The total synthesis of calystegine B4 was achieved in 10 steps from (-)-D-lyxose by using a new synthetic strategy to obtain the requisite protected hydroxylated 4-aminocyclohept-2-en1-one without the problem of regioisomer formation that was a problem in the earlier synthesis of this natural product. The key steps included a Petasis-borono-Mannich reaction and a ring-closing metathesis reaction.

D-Glucosamine trimethylene dithioacetal derivatives: Formation of six- and seven-membered ring amino carbasugars. Synthesis of (-)-calystegine B 3

By virtue of carefully chosen protecting groups, d-glucosamine trimethylene dithioacetal derivatives were successfully oxidized to the corresponding 6-aldehydes. This methodology reverses the donor and acceptor position on a normal open chain sugar and changes the relative position of the N-substituent. From the 6-aldehydes, heptose epoxide derivatives were prepared by a Corey-Chaykovsky reaction, and cyclized by the Corey-Seebach method. Depending on the designed protecting groups, the orthogonally protected six- and seven-membered ring amino carbasugars can be produced selectively and efficiently. (-)-Calystegine B3 was synthesized from one of those products with high yield. This is the first anionic cyclization pathway to calystegine type structures. This journal is The Royal Society of Chemistry.

A short synthetic route to the calystegine alkaloids

An efficient strategy is described for the synthesis of enantiopure calystegine alkaloids. The key step employs a zinc-mediated fragmentation of benzyl-protected methyl 6-iodo-glycosides followed by in situ formation of the benzyl imine and Barbier-type allylation with zinc, magnesium, or indium metal. Stereochemistry in the pivotal allylation is controlled by the choice of the metal. The functionalized 1,8-nonadienes, thus formed, are converted into cycloheptenes by ring-closing olefin metathesis. Regioselective hydroboration and oxidation give the corresponding cycloheptanones, which are deprotected to afford the desired calystegines. Hereby, calystegine B2, B3, and B4 are prepared from D-glucose, D-galactose, and D-mannose, respectively. This route constitutes the shortest synthesis of calystegine B2 and gives rise to the first total syntheses of calystegine B3 and B4.

A short and efficient synthesis of (+)-calystegine B2

A short synthesis of (+)-calystegine B2 from (D)-glucose has been achieved, which involves as the key step a triple domino zinc-mediated reductive ring-opening, imine formation and allylation reaction of 6-iodoglucopyranose.

Short syntheses of enantiopure calystegine B2, B3, and B4

Calystegine B2, B3, and B4 have been prepared in 5 steps from the benzyl protected methyl 6-iodoglycopyranosides of glucose, galactose and mannose, respectively, by using a zinc-mediated domino reaction followed by ring-cl