A. A. Karapetyan

Synthesis and structure of 3-oxopyrano[3,4-c]pyridines

Acylation of the enamine of 2,2-dimethyltetrahydropyran-4-one with acid chlorides produced α-acylpyran-4-ones which give 3-oxopyrano[3,4-c]pyridines when treated with cyanoacetamide.

Cyclization of 4-ureidobutanoic acids in acetic anhydride

A simple method is proposed for synthesizing 1-carbamoyl-2-pyrrolidones by cyclization of 4-ureidobutanoic acids in acetic anhydride.

Synthesis and transformations of polyhedral compounds 12. Stevens rearrangement in the azaadamantane series

Some quaternary salts of 1,3-diaza- and 1,3,5-triazaadamantanes undergo the Stevens rearrangement to give derivatives of the corresponding 1,4-diaza- and 1,3,6-triazahomoadamantanes. The structures of the rearrangement products were proved by IR, PMR, and mass spectroscopy and x-ray diffraction analysis (XDA).

Synthesis of 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane and its reaction with dibromoalkanes

Abstract4-(N′-Benzoylthioureido)-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1′-cyclohexane), which was synthesized from 4-amino-3-ethoxycarbonyl-1,2-dihydrospiro(naphthalene-2,1′-cyclohexane) and benzoyl isothiocyanate, cyclized to give 4-oxo-2-thioxo-1,2,3,4,5,6-hexahydrospiro(benzo[h]quinazoline-5,1′-cyclohexane). Reaction of the latter with 1,2-dibromoethane or 1,3-dibromopropane gave products of intramolecular dialkylation at the S and N(3) atoms.

Investigation of the stereodirection of the Ritter reaction. Crystalline and molecular structure of N-(2-phenethyl)-4-methylpiperid-4-ol and N-(2-phenethyl)-4-methyl-4-acetamido-piperidine

The stereodirection of the Ritter reaction of N-(2-phenethyl)-4-methylpiperid-4-ol to the corresponding amide has been studied. X-ray analysis has shown that the reaction occurs with retention of the configuration about atom C4 of the piperidine ring. Attempts are made to explain the stereodirection of the direction.

Investigation of the stereodirection of the Ritter reaction. Crystaline and molecular structures of N-(2-phenethyl)-2,5-dimethyl-4-phenylpiperid-4-ol and N-(2-phenethyl)-2,5-dimethyl-4-phenyl-4-acetamidopiperidine

The stereodirection of the Ritter reaction of N-(2-phenethyl)-2,5-dimethyl-4-phenylpiperid-4-ol to the corresponding amide has been studied. X-ray analysis has shown that the reaction occurs with retention of the configuration about atom C4 of the piperidine ring.

Relationship between the morphine-like action and the substituent conformation at position 4 in 5-methyl and 3,5-dimethyl derivatives of 1-arylalkyl-4-anilinopiperidines

The most active morphinomimetics currently used in medical practice are members of the 4-anilinopiperidine series or derivatives of fentanyl. It is possible that the molecular skeleton of the known morphine-like substances satisfies well the requirements of the active region of the receptor. Detailed structural analysis of members of this class is therefore justified, with the aim of obtaining a more significant linkage between spatial structure and activity.

Conformation of 4-propionylaniline pharmacophore in stereoisomers of a 2,5-dimethyl derivative of fentanyl (phenaridine)

It is a generally known fact that for a complementary reaction, the structure of the ligand should satisfy certain requirements which are dictated by the steric structure (usually unknown) of the active portion of the receptor. For this reason it is not surprising that the receptor often displays a conformational selectivity. It is also not surprising that this selectivity becomes explicit and significant when compounds serving as ligands are studied with similar physicochemical~and electronic characteristics. In these cases the differences in the biological properties of the ligands can be attributed with a substantial reliability to the differences in the conformations of their molecules. On the other hand, the revelation of a relationship between the conformation and the activity of molecules with a similar molecular structure makes it possible to reliably determine the steric requirements of a receptor for effective interaction with the ligand.

Synthesis and structure of diethyl 2-oxo-1-oxaspiro[4,5]decane-3,4-dicarboxylate

Ethyl 1-oxaspiro[2,5]octane-2-carboxylate reacts with diethyl sodiomalonate in toluene to give diethyl 2-oxo-1-oxaspiro[4,5]decane-3,4-dicarboxylate, which on distillation under goes partial de-ethoxycarbonylation to give ethyl 2-oxo-1-oxaspiro[4,5]decane-4-carboxylate.

Structure of 4-anilinopiperidine analgesics. I. The structure of the 2:1 solvate of 1(e)-(2-phenethyl)-2(e),5(a)-dimethyl-4(e)-(N-propionylanilino)-piperidine bisulfate monohydrate with cyclohexanone

An x-ray diffraction structural analysis was carried out using λCu radiation with 2975 reflections, θ≤64° to R=0.073 for the bisulfate of the major component of the narcotic analgesic, phenaridine (1-(2-phenethyl)2,5-dimethyl-4-(N-propionylanilino)-piperidine citrate). The crystals studied obtained from cyclohexanone are a double solvate containing 1/2 randomly disordered cyclohexanone molecule and one water molecule per formal salt unit. The unit cell parameters for the monoclinic crystals are as follows: a=15.231(2), b=14.946(2), c=13.070(2) Å, β-104.23(1)°, space group P21/c, Z=4. The methyl groups in the compound studied occupy the 2-equatorial and 5-axial positions relative to the piperidine ring. Taking account of the equatorial positions of the substitutents at the 1- and 4-positions of the piperidine ring, the compound designated should be designated the rel-(1R,2R,4S,5R) isomer. The cation has an extended conformation with ordinary geometric parameters. The relative arrangement of the pharmacophoric groups in the cation (benzene rings A and F, piperidine ring D, and the amide fragment) is similar to that for the groups in “T-shaped” morphine-like molecules.