Band 20, Heft 6

The synthetic chemistry of dimethyl N -cyanodithioiminocarbonate is reviewed. The scope and limitation of the most important approaches are discussed.

A convenient and practical protocol was developed to synthesize glycosyl 1,3,4-oxadiazoles from d -glucosamine with good to excellent yields. The key step involved p -TsCl/pyridine-mediated cyclization under mild conditions. Subsequent removal of the acetyl groups in the last step, conducted using the system of NaOMe/MeOH, gave the desired N -acetyl- d -glucosamine 1,3,4-oxadiazole derivatives.

New N , N -disubstituted 7,7-dimethyl-7,8-dihydro-6 H -benzotetrazolothiadiazine-9-amines were synthesized from sodium 1-amino-1 H -tetrazole-5-thiolate and 2-bromo-5,5-dimethylcyclohexane-1,3-dione in multiple steps. The compounds were characterized by 13 C NMR, 1 H NMR, IR, MS, and elemental analysis.

A series of new 10 H -phenothiazines, their sulfones, and ribofuranosides were synthesized and their in vitro antimicrobial assessment was carried out against a representative panel of Gram-positive and Gram-negative bacterial strains and selected fungi species. The 10 H -phenothiazines were prepared using Smiles rearrangement. The sulfone derivatives were synthesized by oxidation of 10 H -phenothiazines using 30% hydrogen peroxide in glacial acetic acid. The ribofuranosides were prepared by treatment of the phenothiazines with β- d -ribofuranosyl-1-acetate-2,3,5-tribenzoate.

Reaction of hydrazones derived from ketones bearing an acceptor substituent adjacent to the carbonyl group (α,α,α-trifluoroacetone and ethyl pyruvate) with Vilsmeier-Haack reagent was studied. In most cases, the method allows for regioselective preparation of 1,3-disubstituted pyrazole-4-carbaldehydes – the products of initial C -electrophilic attack, although in one case, the product resulting from concurrent N - and C -attacks of the electrophile at the hydrazone moiety is observed. Under analogous conditions, the reaction of N -arylhydrazone derived from butanedione leads to the formation of 3-chloro-3-(1-arylpyrazol-3-yl)acrylaldehyde – the product of double formylation at both ketone and hydrazone moieties of the starting material.

This report provides a description of an efficient and simple procedure for the synthesis of 2-azetidinones via a one-pot reaction of imines and carboxylic acids in the presence of silicaphosphine at room temperature. The reagent is cheap and stable. The yields are good to excellent, and the reaction conditions are mild.

The one-pot synthesis of novel 1,4-disubstituted 1,2,3-triazole derivatives derived from homopropargyl alcohol backbones has been accomplished. Triazoles are obtained in good yields from a variety of readily available aromatic and aliphatic halides without isolation of potentially unstable organic azide intermediates.