Rearrangements and cyclizations—XVI: Ring-opening reactions of 1,1-diacetylcyclopropane with hydrazine and hydroxylamine derivatives as the novel synthesis of β-X-ethyl substituted pyrazoles and isoxazoles

The reactions of 1,1-diacetylcyclopropane (1) with a number of hydrazine and hydroxylamine derivatives proceed via cyclopropane ring opening with incorporation of external nucleophile (solvent) to give the 4-β-X-ethyl derivatives of 3,5-dimethylpyrazoles and -isoxazoles, a novel route to these heterocycles. This ring cleavage occurs especially smoothly in water as a solvent. A rationale for this unusually mild nucleophilic cyclopropane ring opening is discussed.     

New Pathway to the Synthesis of Substituted 4H-3,1-Benzoxazines

The intramolecular rearrangement of N-acyl-2-cyclopropylanilines by the action of protic acids gives substituted 4H-3,1-benzoxazines. The reaction proceeds in high yield through the formation of benzoxazine precursors, namely, the corresponding 3,1-benzoxazinium ions, which are stable in acid solution. N-Acylamino-2-alkenylbenzenes, in which the double bond of the alkyl chain is conjugated with the benzene ring, are capable of undergoing a similar rearrangement.     

[3,2]-Sigmatropic Rearrangement of Acyloxy Nitronic Acids into Geminal Acyloxy Nitroso Compounds

Acylation of secondary nitroalkanes is accompanied by [3,2]-sigmatropic rearrangement of acyloxy nitronic acids into geminal acyloxy nitroso compounds which are formed in preparative yields.     

Syntheses of Compounds Active toward Glutamate Receptors: II. Synthesis of Spiro Hydantoins of the Indan Series

The article describes a general procedure for synthesizing hydantoins of the indan series, which makes it possible to obtain bioisosteric analogs of 1-aminoindan-1,5-dicarboxylic acid, a group I metabotropic glutamate receptor antagonist.     

Crystal and molecular structure of 6,6-dimethyl-cis-2,4-diphenyl-3-aza-7-oxabicyclo[3.3.1]nonan-9-one

A method is presented for synthesizing 6,6-dimethyl-2,4-diphenyl-3-aza-7-oxabicyclo[3.3.1]nonan-9-one. The x-ray structure shows that the compound in the crystal exists in the chair-boat conformation with the piperidine ring in the boat form. The two phenyl substituents in the 2- and 4-positions are responsible for such a conformation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1400–1402, October, 1990.     

The use of hexafluoropropene oxide in substitutive fluorination of SbV and BiV oxygen-containing compounds

Reactions of hexafluoropropene oxide with Sb^V and Bi^V oxygen-containing compounds were studied. The E=O (E−O) groups were found to be transformed into the EF₂ (E−F) (E=Sb or Bi) groups. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1652–1653, August, 1998.     

Approach to the synthesis of homoinositols,a new class of <Emphasis Type="Italic">myo</Emphasis>-inositol monophosphatase inhibitors

A new class of structural analogues of inositol (polyhydroxycycloheptanes, homoinositols) is proposed. 2,3,4,4-Tetrachloro-8-octabicyclo[3.2.1]octadiene-2,6, the adduct of the Diels-Alder reaction between tetracyclopropene and furan, is suggested as the key compound in homoinositol synthesis. Its modification leads to the selective preparation of homoinositol stereomers and derivatives.