S. I. Zav'yalov

Meldrum's acid — A reagent for the synthesis of unsaturated γ-lactones and Β-acylacrylic acids

The thermal cyclization of 2,2-dimethyl-5-(2-aryl-2-oxoethyl)-1,3-dioxan-4,6-diones forms 5-aryl-Β,γ butenolides. Regioselective chlorination of 2, 2-dimethyl-5-[2-aryl(alkyl)-2-oxoethyl]-1,3-dioxane-4,6-diones by SO2Cl2 gives the 5-chloro derivatives; these are cleaved by aqueous AcOH to the E-Β-acylacrylic acids, which are synthones for unsaturated γ-lactones.

Chlorinating properties of the trimethylchlorosilane-potassium bromate-DMF system

Abstractβ-Dicarbonyl compounds such as ethyl acetoacetate, dimedone, and Meldrums acid derivatives undergo monochlorination by the action of a mixture of C1SiMe3 and KBrO3 in DMF at ∼20°C.

Synthesis of 4-oxododecanoic and 4-oxododecanedioic acids

A short synthesis is described for 4-oxododecanoic acid starting from 1-decene or 2-decanone and of 4-oxododecanedioic acid from the methyl ester of 9-oxodecanoic acid.

Synthesis of dimethyl Β-oxoadipate

Acetoacetic ester and Meldrums acid provide a new and simple synthesis of dimethyl Β-oxoadipate. This compound is a synthone for some natural and biologically active compounds.

Synthesis of 2-substituted indoles

Abstract2-Substituted indoles are obtained upon the cyclocondensation of (2-R-2-oxoethyl) trimethylammonium bromides.

Synthesis of 4-imidazolin-2-ones

The reaction of α-bromoketones with CO(NH2)2 and AcONH4 in aqueous acetic acid gave substituted 4-imidazolin-2-ones.

ClSiMe3 As a reagent for the crotonic condensation

Trimethylchlorosilane or a mixture of trimethylchlorosilane and zinc chloride may be used as reagents for the crotonic condensation of aldehydes with diethyl malonate and acetylacetone. The corresponding β-chloroketones were obtained upon the reaction of benzaldehyde with acetylacetone, acetophenone, and ωbromoaceto-phenone in the presence of a mixture of trimethylchlorosilane and zinc chloride.

Synthesis of 4-methyl-5-alkyl-2-imidazolinones

Conclusions4-Methyl-5-alkyl-2-imidazolinones were synthesized by heating 3-halo-2-alkanones with a mixture of piperidine, N,N-diethylacetamide, urea, zinc chloride and magnesium carbonate.

Meldrum's acid as a reagent for the synthesis of 4-alkanolides

Conclusions1.1-Bromoalkanones in the presence of sodium acetate in DMF selectively monoalkylate Meldrums acid (2,2-dimethyl-4,6-dioxo-1,3-dioxane).2.Cleavage of the monoalkylation products, namely, 2,2-dimethyl-4,6-dioxo-5-(2-oxoalkyl)-1,3-dioxanes, by aqueous acetic acid with subsequent reduction by NaBH4 and cyclization as well as selective reduction of the monoalkylation products and subsequent thermal cyclization give 4-alkanolides.

Synthesis of 7-alkylpterins

ConclusionsCyclocondensation of 2,5,6-triamino-4-oxo-3,4-dihydropyrimidine with 1-phthalimido-2-alkanones in aqueous piperidine has given 7-alkylpterins.