Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

A practical and high-yielding Schmidt reaction for the synthesis of fused tetrazoles from bile acid precursors was developed. Mild reaction conditions using TMSN3 instead of hydrazoic acid as an azide source produced good yields of the desired tetrazoles. These conditions could be applied to other steroidal precursors. Additionally, an improved methodology for the synthesis of different ketone and enone precursors from cholic acid, deoxycholic acid, and chenodeoxycholic acid was established. Newly obtained tetrazole derivatives were characterized by NMR and X-ray diffraction spectroscopy. In a number of cases, preliminary antiproliferative tests of new compounds showed strong and selective activity towards certain tumor cell lines.

Reaction mechanism of copper azide nanowires array

In-situ growth of copper azide has endowed this highly sensitive primary explosive new life, but its mechanism study is not enough to support its in-depth study. Hence, azidation reaction was conducted on highly ordered copper nanowires array, which could provide effective channels for gas phase reactant (hydrazoic acid, HN3) to penetrate the solid, further study the mechanism of azidation reaction on copper azide nanowires array, and clarify the relationship between the microstructure and its azidation degree. Gas–solid in-situ azidation technique was used for this in-depth study. The effects of reaction temperature on formation of gaseous HN3 were studied by isothermal thermogravimetry. The azidation results were analyzed by SEM and XRD, the effects of the reaction time, diameter of copper nanowires array precursor and oxidation degree on the azidation degree were studied in detail. This work not only provided deep investigation on the azidation process, but also offered effective guidance for the synthesis of copper azide nanowires array.

Synthesis of aminonaphthoquinone derivatives with Ceric Ammonium Nitrate (CAN) as a catalyst: NMR characterization and in silico reaction mechanism

Three different aminonaphthoquinones of great interest in medicinal chemistry due to their diverse biological activities were more efficiently synthesized and characterized starting from naphthoquinones with hydrazoic acid in the presence of ceric ammonium nitrate (CAN). We have previously reported a highly time demand synthesis of 2-amino-1,4-naphthoquinone and 2-amino-3-methyl-1,4-naphthoquinone in the absence of the CAN catalyst. In the current study, we have also obtained 3-amino-5-hydroxy-1,4-naphthoquinone and reduced all reaction times in the presence of CAN as a catalyst. Reaction rates have been increased to circa three times their original times. All aminonaphthoquinones have been characterized by NMR, vibrational, and chromatographic techniques. Additionally, we have proposed a reaction mechanism for the amination of naphthoquinone derivatives in an acid medium, based on in-depth DFT calculations.

Regioselective and Stereodivergent Synthesis of Enantiomerically Pure Vic-Diamines from Chiral β-Amino Alcohols with 2-Pyridyl and 6-(2,2′-Bipyridyl) Moieties

In this report, we describe the synthetic elaboration of the easily available enantiomerically pure β-amino alcohols. Attempted direct substitution of the hydroxyl group by azido-functionality in the Mitsunobu reaction with hydrazoic acid was inefficient or led to a diastereomeric mixture. These outcomes resulted from the participation of aziridines. Intentionally performed internal Mitsunobu reaction of β-amino alcohols gave eight chiral aziridines in 45–82% yield. The structural and configuration identity of products was confirmed by NMR data compared to the DFT calculated GIAO values. For 1,2,3-trisubstituted aziridines slow configurational inversion at the endocyclic nitrogen atom was observed by NMR at room temperature. Moreover, when aziridine was titrated with Zn(OAc)2 under NMR control, only one of two N-epimers directly participated in complexation. The aziridines underwent ring opening with HN3 to form the corresponding azido amines as single regio- and diastereomers in 90–97% yield. Different results were obtained for 1,2-disubstituted and 1,2,3-trisubstituted aziridines. For the later aziridines ring closure and ring opening occurred at different carbon stereocenters, thus yielding products with two inverted configurations, compared to the starting amino alcohol. The 1,2-disubstituted aziridines produced azido amines of the same configuration as the starting β-amino alcohols. To obtain a complete series of diastereomeric vic-diamines, we converted the amino alcohols into cyclic sulfamidates, which reacted with sodium azide in SN2 reaction (25–58% overall yield). The azides obtained either way underwent the Staudinger reduction, giving a series of six new chiral vic-diamines of defined stereochemistries.

Convenient Synthesis of Ethyl 5-Oxohomoadamantane-4-carboxylate: A Useful Precursor of Polyfunctional Homoadamantanes

A facile and convenient synthesis of ethyl 5-oxohomoadamantane-4-carboxylate is reported, and its chemical properties as a cage analogue of acetoacetic ester are investigated. Various derivatives of homoadamantane were synthesized through the reaction of 5-oxohomoadamantane-4-carboxylate with electrophilic agents, binucleophiles, and hydrazoic acid. Some new unusual products were obtained by the reaction of that β-keto ester with nitric acid and nitrosyl chloride. Cage compounds synthesized could be used as precursors for the diverse condensed heterocyclic compounds with potential viral ion channel abrogating activity that possess conformationally rigid lipophilic moieties.

Investigating the reaction pathways of chemical functionalization of C20 fullerene by nitrile oxide and azide; A computational study

In this study, the interactions between nitrile oxide (fulminic acid) and azide (hydrazoic acid) with the C[Formula: see text] fullerene were investigated and their priority in reacting and functionalizing surface of this fullerene were compared with each other. The results show that the 1,3-dipolar cycloaddition reaction between fulminic acid and C[Formula: see text] fullerene could occur faster than this reaction by hydrazoic acid. Therefore, nitrile oxide group as a dipole is much preferred compared to the azide functional group in reacting with the surface of C[Formula: see text] fullerene. In addition, the calculated adsorption energy and electronic density of state, DOS plots for the related species confirmed that the C[Formula: see text] fullerene can be used as sensors for sensing the hydrazoic acid and fulminic acid molecules.