C-Nucleosides and related compounds. VIII. Synthesis of 5-(4′β-hydroxymethyl-2′β,3′α-dihydroxycyclopent-1′β-yl)-6-azauracil

1976 ◽  
Vol 54 (18) ◽  
pp. 2925-2934 ◽  
Author(s):  
G. Just ◽  
R. Ouellet
Keyword(s):  
Double Bond ◽  
Title Compound ◽  
Sodium Methoxide ◽  
Alder Reaction ◽  
Oxidative Cleavage ◽  
Diels Alder ◽  
Keto Ester ◽  
Diels Alder Reaction ◽  
Related Compounds

Starting from the Diels–Alder reaction of trans-β-bromoacrylic acid with cyclopentadiene, a synthesis of the substituted bicycloheptene 8 is described. The stereochemistry of the substituents is clearly defined. Oxidative cleavage of the double bond in the compound 8c afforded an acid keto ester 10 that was treated with thiosemicarbazide. Treatment of the resulting thiosemicarbazone 11 with sodium methoxide gave a 3-thioxo-1,2,4-triazine-5-one compound that was converted into the title compound.

The synthesis of trisubstituted cyclopentadienes and their reactivity in the intramolecular Diels–Alder reaction

1984 ◽  
Vol 62 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Sandra J. Alward ◽  
Alex G. Fallis
Keyword(s):  
Adverse Effect ◽  
Alder Reaction ◽  
Diels Alder ◽  
Keto Ester ◽  
Diels Alder Reaction ◽  
General Method

The intramolecular Diels–Alder reactivity of several trisubstituted cyclopentadienes is described and a general method for their preparation reported. In general, sidechain keto-ester functionality has an adverse effect on these internal cycloadditions.

Exploratory synthetic investigations related to 12a-deoxypillaromycinone

2002 ◽  
Vol 80 (6) ◽  
pp. 728-738 ◽  
Author(s):  
Lan Wang ◽  
Sanath K Meegalla ◽  
Cheng-Lin Fang ◽  
Nicholas Taylor ◽  
Russell Rodrigo
Keyword(s):  
Double Bond ◽  
Catalytic Hydrogenation ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Step Procedure ◽  
Key Steps

Furfural is converted to suitably substituted AB synthon 21 for 12a-deoxypillaromycinone in 10 steps by a sequence involving the following key steps: intramolecular Diels-Alder reaction of a furan, 5-endo-trig cleavage of the oxabicyclo adducts 18, and catalytic hydrogenation of the double bond of a tetrasubstituted enone to produce 19. Enones 21a and 21b obtained by dehydrogenation of 19a and 19b, respectively, are then annulated with ethyl 2-methoxy-6-methylbenzoate in a four-step procedure to generate tetracyclic products 25 in 14 steps from furfural.

Total synthesis of androstanes

1979 ◽  
Vol 57 (24) ◽  
pp. 3356-3358 ◽  
Author(s):  
Masatoshi Kakushima ◽  
Jagabandhu Das ◽  
Gary R. Reid ◽  
Peter S. White ◽  
Zdenek Valenta
Keyword(s):  
Total Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
Keto Ester ◽  
Diels Alder Reaction ◽  
Androstane Derivatives

A total synthesis of androstane derivatives is described. The desired configuration at C8 and at C13 is achieved in a ring C forming SnCl4-catalyzed Diels–Alder reaction. The preparation of methyl Z-2-methyl-4-oxo-2-pentenoate and the cyclization of a keto ester to a steroid 15,17-dione are also reported.

Synthesis of (±)-epiisopodophyllotoxin

1983 ◽  
Vol 61 (3) ◽  
pp. 573-575 ◽  
Author(s):  
Margaret B. Glinski ◽  
Tony Durst
Keyword(s):  
Title Compound ◽  
Dimethyl Fumarate ◽  
Dimethyl Acetal ◽  
Alder Reaction ◽  
Diels Alder ◽  
Carbon Skeleton ◽  
Diels Alder Reaction ◽  
Alder Adduct

The synthesis of (±)-epiisopodophyllotoxin commencing with 6-bromopiperonal dimethyl acetal is described. The carbon skeleton of isoepipodophyllotoxin was assembled via a Diels–Alder reaction between the hydroxyquinodimethane generated photochemically from 6-(3′,4′,5′-trimethoxybenzyl)-piperonal, obtained from the bromoacetal above, and dimethyl fumarate. This Diels–Alder adduct was converted in five steps into the title compound. The overall yield for the seven steps was 15%.

Total synthesis of amphilectane-type diterpenoids: (±)-8,15-diisocyano-11(20)-amphilectene

1993 ◽  
Vol 71 (9) ◽  
pp. 1484-1494 ◽  
Author(s):  
Edward Piers ◽  
Montse Llinas-Brunet ◽  
Renata M. Oballa
Keyword(s):  
Total Synthesis ◽  
Alder Reaction ◽  
Diels Alder ◽  
Allylic Oxidation ◽  
Keto Ester ◽  
Efficient Transformation ◽  
Diels Alder Reaction ◽  
Product Mixture

A total synthesis of the structurally novel, antimicrobial diterpenoid (±)-8,15-diisocyano-11(20)-amphilectene (2) is described. Alkylation of 2-methoxycarbonyl-3-methylcyclohexanone (13) with (E)-1-(tert-butyldimethylsiloxy)-6-iodo-3-(trimethylstannyl)-2-hexene (14) provided, stereoselectively, the functionalized keto ester 15, which was converted efficiently into the diene 17. Diels–Alder reaction of 17 with acrolein, followed by base-catalyzed equilibration of the resultant product mixture, gave the aldehydes 19 (58%) and 20 (29%). Allylic oxidation of the alkene 24 (derived from 19) afforded the enone 25. Reduction (Na, NH3, t-BuOH) of 25 gave 28, which was converted, via a sequence of eight synthetic steps, into the diacid 45. Efficient transformation of the carboxyl functions of 45 into isonitrile groups completed the synthesis of (±)-2.

Diels-Alder Reaction Curing of Chlorobutyl Rubber by bis-Maleimides

1989 ◽  
Vol 62 (1) ◽  
pp. 42-54 ◽  
Author(s):  
K. Ho ◽  
R. Steevensz
Keyword(s):  
Zinc Oxide ◽  
Double Bond ◽  
Chain Length ◽  
Crosslinking Agent ◽  
Alder Reaction ◽  
Diels Alder ◽  
Diels Alder Reaction ◽  
Electronic Distribution ◽  
Curing Agents ◽  
Chlorobutyl Rubber

Abstract Different bis-maleimides are found to have different efficiencies and reactivities in the crosslinking of CIIR in the presence of zinc oxide. Although the degrees of crosslinking of CIIR by bis-maleimides cannot be defined absolutely, some trends concerning the efficiencies of the crosslinking are evident. In general, the aromatic bis-maleimides gave higher degrees of crosslinking than the aliphatic analogs. The reactivity and crosslinking efficiency of an individual bis-maleimide is very much affected by its end-to-end chain length and its electronic distribution, resulting from the interaction between the maleimide groups, and from the interaction between the maleimide groups and other functional groups present in the same molecule. The longer the bis-maleimide molecule and the more electron deficient the maleimido double bond, the greater its effectiveness as a crosslinking agent. Other curing mechanisms, possibly including polymerization of the maleimido groups, appear to be operative when using aromatic bis-maleimides as curing agents for CIIR.

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