Synthesis of 3-aryl-5-dichloromethyl-1H-pyrazole-1-carboxamides from 1-aryl-3,4,4-trichlorobut-3-en-1-ones

The reaction of 1-aryl-3,4,4-trichlorobut-3-en-1-ones with semicarbazide hydrochloride in the presence of sodium acetate is accompanied by prototropic allylic rearrangement, leading to the formation of two isomeric products, semicarbazones of the initial ketones and 1-aryl-3,4,4-trichlorobut-2-en-1-one semicarbazones. The latter undergo heterocyclization in the presence of triethylamine to give the corresponding 3-aryl-5-dichloromethyl-1H-pyrazole-1-carboxamides.     

Synthesis and spatial structure of the geometrical isomers of 4-substituted 1-tert-butyl-3-methyl-piperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines

In order to study the interrelationship between the structure, reactivity, and spectroscopic characteristics of the stereoisomeric piperidines, starting from 1-tert-butyl-3-methylpiperidin-4-one the synthesis has been performed of the geometric isomers of some 4-substituted 1-tert-butyl-3-methylpiperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines. The spatial structures of the compounds obtained have been determined by IR and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1056–1061, August, 1973.     

Synthesis and three-dimensional structures of the cis and trans isomers of 3-methyl-1-tert-butyl-4-acetyl- and 3-methyl-1-tert-butyl-4-carbomethoxy-4-piperidols

The cis and trans isomers of 3-methyl-1-tert-butyl-4-acetyl- and 3-methyl-1-tertbutyl-4-carbomethoxy-4-piperidols, the three-dimensional configurations of which were established by means of their IR and UV spectra, were synthesized in order to study the interrelationship between the structure and reactivity of stereoisomeric piperidines.Translated from Khimiya Geterotsiklicheskikh Soedinenni, No.12, pp. 1659–1665, December, 1973.     

Synthesis of chiral 3-aryl-1-methyl-3-trifluoromethyl-3H-pyrrolizines

Russian Journal of Organic Chemistry -     

Some 2-aryl-5-azaindandiones-1, 3

Condensation of cinchomeronic acid with p-nitrophenylacetic acid, of 2, 6-dimethylcinchomeronic acid with phenylacetic acid, and p-nitrophenylacetic acid in acetic anhydride solution in the presence of triethylamine followed by rearrangement of the condensation products with sodium methoxide gives 2-(p-nitrophenyl)-5-azaindandione-1, 3, 4, 6-dimethyl-2-phenyl-5-azaindandione-1, 3, and 4, 6-dimethyl-2-(p-nitrophenyl)-5-azaindandione-1, 3. Reaction of the alkali metal salts of these compounds with dimethyl sulfate leads to alkylation at the nitrogen atom, and formation of N-methyl betaines of the corresponding 5-azaindandiones. 2-Aryl-5-azaindandiones and their N-methyl betaines are dark in color (black to reddish brown), sparingly soluble, and decompose at 250-350°.     

A photochemical synthesis of 3-aryl-1-methylquinolinones

A number of fluorescent 3-aryl-1-methylquinolinones 3 were synthesized by the regiospecific photocoupling reaction of 3-halo-1-methylquinolinones 1 with aromatic and heteroaromatic compounds 2 . An unusual photocoupling product 4 was obtained in the photolysis of 3-iodo-1-methylquinolinone in the presence of benzene. The structure of 4 was unequivocally established by an X-ray crystallographic analysis.     

New synthesis of substituted 3-aryl-1-naphthaldehydes

A general, unequivocal procedure for the preparation of specifically substituted 3-aryl-1-naphthaldehydes was developed. Benzylmagnesium bromides with 5-aryl-2, 2-dimethyl-4-pentene-3-ones (12) gave exclusively 1,4-addition products, 5,6-diaryl-2,2-dimethyl-3-hexanones (13). The hexanones on oxidation with peracetic acid gave 3,4-diarylbutanoic acids (14), which were cyclized to tetralones (15). The tetralones on treatment with MeMgI followed by dehydration and dehydrogenation gave 3-aryl-1-methylnaphthalenes (10), which were converted into corresponding aldehydes (11). When benzylmagnesium bromides were added to 4-aryl-3-butene-2-ones (1), mixtures of 1,2 and 1,4-addition products were formed. Further treatment of these mixtures also yielded the desired methylnaphthalenes along with various identified side products.     

IR absorption spectra of 1-aryl-3-pyrazolidones

An examination of the frequencies and intensities of the valence vibration bands of carbonyl groups established that the phenyl group interacts with the C=O group of 1-phenyl-3-pyrazolidone and its m- and p-tolyl derivatives in solution. It is assumed that the interaction is accomplished through the N₁ and N₂ atoms in the sp² state. 1-Phenylpyrazolidone derivatives are strongly associated in CC1₄ and CHCl₃ solutions. The association decreases on passing from CCl₄ to CHCl₃ solutions and when there are methyl groups in the ortho positions of the phenyl rings. The energy of association between the 1-phenylpyrazolidones and organic bases (acetonitrile, ethyl acetate, and dioxane), evaluated from the shift in _nh, is 1.36–3.5 kcal/mole. The frequencies and integral intensities of the bands of the C=O and NH groups in chloroform were measured.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1678–1682, December, 1970.     

Electron impact fragmentations of 1- and 3-aryl-3-buten-1-ols

The electron impact fragmentation of 1- and 3-aryl-3-buten-1-ols show several distinguishing fragmentations. α-Cleavage predominates in the fragmentation of the 1-aryl-3-buten-1-ols to such an extent that molecular ions of only low intensity are observed. The ion resulting from α-cleavage fragments readily with the loss of the ring substituent to the phenyl ion. An intense molecular ion is observed in the 3-aryl series and a loss of 70 u is a major fragmentation in this series. Based on deuterium labeling studies, this unique fragmentation was explained by a hydroxylic hydrogen migration to the ring accompanied by the loss of allene and formaldehyde. Other major fragmentations observed in the 3-aryl series are: a McLafferty-type rearrangement (loss of formaldehyde), loss of 33 u (water + methyl radical), and the loss of 43 u (C₂H₃O and C₃H₇). The proposed mechanisms have been substantiated by deuterium labeling and high resolution mass spectrometry. Substituent effects play a major role in the 3-aryl series, but are insignificant in the 1-aryl series.     

A novel synthesis of 1-aryl-3-piperidone derivatives

A novel method to construct the 1-aryl-3-piperidone scaffold is described here. Starting from 3,5-dichloroaniline, a seven-step synthesis, without the use of protecting groups, generates the desired 3-piperidone ring in an overall yield of 30% through a key Morita–Baylis–Hillman reaction and ring-closing metathesis, providing easy access to diverse and useful heterocycles.     

Synthesis of cis-1-methyl-2-aryl-3-aroylaziridines

trans-1-Methyl-2-aryl-3-aroylaziridines readily undergo epimerization to give the corresponding cis isomers in high yields in the presence of catalytic amounts of quaternary ammonium bases (trimethylbenzylammonium or triethylmethylammonium hydroxide). The structures of the compounds obtained were established on the basis of the IR and PMR spectra and the results of elementary analysis.Translated from Khimiya Geterotsilicheskikh Soedinenii, No. 10, pp. 1353–1355, October, 1980.