Proposed molecular structures for 3-butenenitrile, 2-methyl-3-butenenitrile,and 3-methyl-3-butenenitrile

Molecular structures are proposed for the two conformers, s-cis and gauche, existing for 3-butenenitrile and 3-methyl-3-butenenitrile, and for the three predicted conformers of 2-methyl-3-butenenitrile, using structural parameters transferred from related molecules. The proposed structures for the two conformers of 3-butenenitrile have principal moments of inertia which agree well with experimental values obtained by microwave spectroscopy, except for the gauche I_A moment. The experimental value of I_A for the gauche conformer of 3-butenenitrile could only be determined at the time with a low degree of precision, hence the microwave spectrum of this conformer should probably be reexamined.     

The i.r. spectra of 3-methyl-2-butenenitrile and 3-methyl-3-butenenitrile

A commercial sample of supposedly 3-methyl-3-butenenitrile was separated by gas chromatography into two components. Analysis of the i.r. and NMR spectra of these two components showed that the original mixture contained 25% 3-methyl-3-butenenitrile and 75% 3-methyl-2-butenenitrile, and that an i.r. spectrum recently reported in this journal [1] for 3-methyl-3-butenenitrile was actually that of 3-methyl-2-butenenitrile. Thus, the spectral data reported for 3-methyl-3-butenenitrile [1] and the resulting conclusions regarding the nature of the conformational equilibrium in this molecule should be disregarded.     

Preparation of 3-methyl-4-vinyl-1,2,5-oxadiazole and 3-methyl-4-vinyl-1,2,5-thiadiazole

Short and high yielding preparations of 3-Methyl-4-vinyl-1,2,5-oxadiazole ( 6a ) and 3-Methyl-4-vinyl-1,2,5-thiadiazole ( 6b ) are described.     

Comparative reactivity of 3-methyl-5-phenylisoxazole and 3-methyl-5-phenylisothiazole against electrophilic compounds

A comparative study of reactions of 3-methyl-5-phenylisoxazole and 3-methyl-5-phenylisothiazole with electrophilic compounds in the presence of n-BuLi, LICA or LICA-TMEDA is reported. By using LICA-TMEDA, regioselective reactions of the heterocyclic compounds at the C-3 methyl group are obtained. With n-BuLi or LICA and the isoxazole derivative a product mixture at the C-4 position and the C-3 methyl group is found. In the case of isothiazole compound, only with methyl iodide and n-BuLi, the dialkylated product at both positions is formed.     

Base-catalyzed isomerization of 3-methyl-3-norcarene epoxides

Conclusions A study was made of the isomerization of the trans- and cis-3,4-epoxy~3-methylnorcaranes by Et₂NLi in ether and t-BuOK in pyridine. The action of both bases on the trans-epoxide gives comparable amounts of 4-hydroxy-3-methyl-2-norcarene and 3-hydroxy-3-methyl-4-norcarene. In the reactions of the cis-epoxide the composition of the reaction mixture depends on the employed reagent: in the presence of Et₂NLi the main product is 4-hydroxy-3-methylnorcarane, while with t-BuOK it is 3-hydroxy-3-methyl-4-norcarene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1638–1640, July, 1982.     

Oxides of 3-methyl-1,2,4-benzotriazine

The previously prepared 3-methyl-1,2,4-benzotriazine oxide¹ is shown to be the 4-oxide 5. Synthesis and structures of other isomeric and related oxides are described. A modification of a previously described synthesis of 1,2,4-benzotriazines produces purer products in higher yields.     

Cyanoethylation of 3-methyl-2-azafluorene

3-Methyl-9,9-di(-cyanoethyl)-2-azafluorene was obtained from 3-methyl-2-azafluorene via the Michael reaction and was converted to the dibasic acid and its diester. Dieckmann condensation of the latter and subsequent hydrolysis gave 3-methyl-4-oxospiro(2-azafluorene-9,1-cyclohexane).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1668–1670, December, 1972.     

Acylation of 3-methyl-2-azafluorene

Acylation of 3-methyl-2-azafluorene under various conditions yielded the enol forms of its (C₍₉₎ acyl derivatives, whereas the ketol form was also isolated in the case of the p-nitrobenzoyl derivative. The character of the compounds formed in the reaction of 3-methyl-2-azafluorene with benzoyl chloride and acetic anhydride is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 963–967, July, 1976.     

Synthesis of chalcones bearing 2-hydroperoxy-3-methyl-3-butenyl or 2-hydroxy-3-methyl-3-butenyl group from prenylated chalcones

Abstract

Chalcones bearing 2-hydroperoxy-3-methyl-3-butenyl or 2-hydroxy-3-methyl-3-butenyl groups, such as xanthoangelol E (1a), xanthoangelol D (2a), psorachalcone A (2?b), xanthohumol D (2c), and related derivatives were first synthesized by using the ene reaction of prenylated chalcones with singlet oxygen.     

3-Ferrocenyl-1-methyl- and 1-ferrocenyl-3-methylcyclopropenes

Dehydrobromination of isomeric 3-bromo-1-ferrocenyl-2-methylcyclopropanes afforded 3-ferrocenyl-1-methyl- and 1-ferrocenyl-3-methylcyclopropenes. These undergo smooth opening of the three-membered ring to give 1- and 2-ferrocenylbuta-1,3-dienes and 1- and 2-methyl-1H-cyclopentaferrocenes; with 1,3-diphenylisobenzofuran they give the classical Diels-Alder adducts.