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The reaction of aryl isothiocyanates with nonstabilized azomethine ylides generated in situ by various methods was studied. It was established that the use of N-(methoxymethyl)-N-(trimethylsilylmethyl)benzylamine in the presence of trifluoroacetic acid in the role of a catalyst led to the formation of (Z)-N-aryl-3-benzylthiazolidin-5-imines in 22–47% yields.

Azomethine ylides obtained in situ from proline or sarcosine and indenoquinoxalinones reacted with nitrostyrenes upon heating in isopropanol for 4–5 days, resulting in the formation of spiro[indeno[1,2-b]quinoxaline-11,3'-pyrrolizidines] and spiro[indeno[1,2-b]-quinoxaline-11,2'-pyrrolidines] with various regiochemistry.

Conjugated unsaturated carbonyl compounds with weak CH or NH acidity were used in a three-component reaction with sarcosine and formaldehyde, forming (3+2) cycloaddition products in 32–73% yields. The conversion was estimated from NMR data and strongly depended on the acidity of dipolarophile and the steric accessibility of its double bond.

4-Aryl-6-(trifluoromethyl)-2-pyrones reacted with the nonstabilized azomethine ylide obtained from sarcosine and formaldehyde under reflux in benzene for 6 h, resulting in [3+2] cycloaddition that gave 4-aryl-6-methyl-7a-(trifluoromethyl)-2,4a,5,6,7,7a-hexahydropyrano-[2,3-c]pyrrol-2-ones in 42–56% yields. In the case of 4-aryl-3-carbethoxy-6-(trifluoromethyl)-2-pyrones, besides the respective pyrano-[2,3-c]pyrrolidines (66–71% yields) also 4-aryl-1-methyl-2-(trifluoromethyl)pyrroles were isolated as minor products.

The reaction of chromone-3-carboxylic acid with indoles in boiling ethanol proceeds as a 1,4-nucleophilic addition with successive opening of the pyrone ring and decarboxylation to afford a series of previously unknown trans-indolyl chalcones in 27–60% yields.

3-Carbamoylchromones reacted with cyanoacetamides in the presence of sodium ethoxide in refluxing ethanol, forming 2-amino-5-aroyl- 6-oxo-1,6-dihydropyridine-3-carboxamides in 50–88% yields.

Gas chromatography has been used to investigate the products accompanying tetrahydrofuran prepared by hydrogenation of furan, without isolating the latter pure from the gas mixture obtained by decarbonylating furfural over oxide catalysts. A number of unknown impurities accompanying tetrahydrofuran and furan, are identified. It is found that tetrahydrofuran contains isopropanol, along with furan,α-methylfuran, andα-methyltetrahydrofuran. Furan itself containsα-methylfuran, and a number of unknown impurities, among them acetone. Ethane is found among the gaseous products of decarbonylation. Thus over Zn and Mn oxide catalysts there is joint hydrogenolysis of the furan ring, and ring opening at positions 1–5 and 3–4.