Ya. F. Freimanis

Protolytic cleavage of derivatives of 2,5-dimethoxy-2,5-dihydrofuran

By analysis of the products from the protolytic cleavage of methyl 3-(2,5-dialkoxy-2,5-dihydro-2-furyl)propionate (I) in the presence of mixed nucleophiles and investigation of their mutual transformations the main paths in the dissociation of the protonated molecule of (I), with the formation of both linear cleavage products (derivatives of 1,4-diketones and 4-ketopimelic acid) and furylcarbinol derivatives, were determined.

Total synthesis and properties of prostaglandins. 40. Synthesis ofβ-Oxyaminovinyl bicyclic γ-lactones

Acetylation of oxyiminomethyl bicyclic y-lactones gave the corresponding N-acetyl-β-oxyaminovinyl derivatives.

Total synthesis and properties of prostaglandins 34. Synthesis and x-ray structural analysis of (+)4-(carboxymethyloxyiminomethyl)-2-oxabicyclo-[3.3.0]-6-octen-3-one

The reaction of α-formyl-γ-lactones with O-substituted hydroxylamines has been investigated. An x-ray structural investigation has been carried out on (+)4-(carboxymethyloxyiminomethyl)-2-oxabicyclo[3.3.0]-6-octen-3-one.

Total synthesis and properties of prostaglandins 35. Synthesis and properties of 4-carbomethoxy-alkylaminomethylene-(+)2-oxabicyclo[3.3.0]-6-octen-3-ones

Reaction of (+)4-mesyloxymethylene-2-oxabicyclo[3.3.0]-6-octen-3-one with Ω-amino acids of different lengths gave (+)4-carbomethoxyalkylaminomethylene-2-oxabicyclo[3.3.0]-6-octen-3-ones. For the γ-aminobutyric ester, the corresponding aminomethylene derivative was obtained both in the linear and the cyclic forms. Acylations of the synthesized enamino lactones by acetyl and benzoyl chlorides were investigated.

Total synthesis and properties of prostaglandins. 36. Condensation of (+)2-oxabicyclo[3.3.0]-6-octen-3-one with furylacrolein and furylpropionic aldehyde

A study was made of the condensation of bicyclic γ-lactone I with furylacrolein and furylpropionic aldehyde. Significant differences were observed in the reactivity of the aldols obtained, and in the stereochemical trend of their dehydration reaction.

Total synthesis and properties of prostaglandins 30. Modification of (1S,5R)-2-oxabicyclo[3.3.0]-6-octen-3-one at the ?-carbon atom

Derivatives of α-alkyl-, α-alkylidene-, and α-hydroxymethylene-2-oxabicyclo[3.3.0]-6-octen-3-one were obtained. The possibility of functional substitution of the bicyclic γ-lactones at the α position to the carbonyl group was thereby demonstrated.

Analogues of prostacyclin (PGI2) modified in the 2-oxabicyclo[3.3.0]octane fragment (review)

A review is given of the synthetic analogs of the prostacyclins having greater chemical and metabolic stability than prostacyclin itself. Possible routes for synthesis are discussed.

Thermal transformations of methyl 3-(2,5-dimethoxy-2,5-dihydro-2-furyl)propionate

The primary products of the pyrolysis of diastereomers of methyl 3-(2,5-dimethoxy-2,5-dihydro-2,5-dihydro-2-furyl)propionate are methyl 3-(5-methoxy-2-furyl)- -and 3-(5-methoxy-2,5-dihydro-2-furylidene)propionates. The pyrolysis products also contain methyl 3-(2-furyl)acrylate, whereas methyl 3-methoxy-3-(2-furyl)-propionate is formed when the pyrolysis is carried out in the presence of p-toluenesulfonic acid.

Cyclic ?-aminovinylimines: VI. Formation of isoquinolones and isoindolones in the oxidation of 2-aryl-1-phenylamino-3-phenyliminoindenes

Abstract2-Substituted 1-phenylamino-3-phenyliminoindenes have been found to be readily oxidized by atmospheric oxygen. The structure of the resulting 3-aryl-3-hydroxy-2-phenyl-4-phenyliminodihydroisoquinol-1-ones has been shown by chemical and spectroscopic methods. The comparative oxidizability of enamines of several types is discussed on the basis of quantum-mechanical calculations by the LCAO MOH method.

Synthesis of derivatives of 1, 2, 3, 4-tetrahydro-4-azafluoren-3,9-diones

Cyclization of amides of α-carbamido-β-(indan-1, 3-dione-2-yl) hydrocinnamic acid gives 1-aryl-2-carbamido-1, 2, 3, 4-tetrahydro-4-azafloren-3, 9-dione. Alkaline and acid hydrolysis of these compounds are investigated.