Tetrazolo[1,5-a]quinolines and 1,2,3-Triazolo[1,5-a]quinazolines by the Action of Cyanocarbanions on 2-azidoarylcarbonyl Compounds

Synthesis of 4-(Phenylchalcogenyl)tetrazolo[1,5-a]quinolines by Bicyclization of 2-Azidobenzaldehydes with Phenylchalcogenylacetonitrile

A general methodology to access valuable 4-(phenylchalcogenyl)tetrazolo[1,5-a]quinolines was developed by the reaction of 2-azidobenzaldehyde with phenylchalcogenylacetonitriles (sulfur and selenium) in the presence of potassium carbonate (20 mol%) as a catalyst. The reactions were conducted using a mixture of dimethylsulfoxide and water (7:3) as solvent at 80 °C for 4 h. This new methodology presents a good functional group tolerance to electron-deficient and electron-rich substituents, affording a total of twelve different 4-(phenylchalcogenyl)tetrazolo[1,5-a]quinolines selectively in moderate to excellent yields. The structure of the synthesized 4-(phenylselanyl)tetrazolo[1,5-a]quinoline was confirmed by X-ray analysis.

tert-Butyl nitrite-mediated radical cyclization of tetrazole amines and alkynes toward tetrazolo[1,5-a]quinolines

A general and efficient radical cyclization of 1H-tetrazol-5-amines and alkynes toward tetrazolo[1,5-a]quinolines is established for the first time. The annulation mediated by tert-butyl nitrite takes place expeditiously within 10 minutes under mild conditions. Without using external additives or excitation, the tetrazolo[1,5-a]quinoline derivatives are obtained in moderate to good yields, along with high regioselectivities for unsymmetrical alkynes and broad functional tolerance features. The reaction is exemplified to occur via a radical process, with aryl radicals synergistically generated from tert-butyl nitrite, water and tetrazolate-diazonium salts.

Synthesis of novel pyrazole derivatives using organophosphorus, stibine, and arsine reagents and their antitumor activities

The reactions of 5-azido-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (azidopyrazole) with several classes of organophosphorus reagents: phosphonium ylides, Wittig-Horner reagents, dialkylphosphonates, trialkylphosphites, tris(dialkylamino)phosphanes, triphenylstibane, triphenylarsane, and Lawesson’s reagent are reported. Structural reasoning for the new products was based on compatible analytical and spectral data. The cytotoxic activity of most of the new products was evaluated against human breast carcinoma cell line (MCF7) and human hepatocellular carcinoma cell line(HepG2). Certain tested compounds showed promising results.

Preparation and Reactions of 2-azidoquinoline-3-carboxaldehyde with Primary Amines and Active Methylene Compounds

Preparation of 2-azidoquinoline-3-carboxaldehyde has been attempted and its tautomerism has been discussed. The reactivity of 2-azidoquinoline-3-carboxaldehyde towards primary amines, hydrazines and active methylene compounds has been investigated. Analytical and spectroscopic measurements have assisted the assignment of appropriate structures to the new reaction products.

Microwave assisted synthesis of triazoloquinazolinones and benzimidazoquinazolinones

BACKGROUND

Benzimidazoquinazolinones and related quinazolines are classes of heterocycles that are of considerable interest because of the diverse range of their biological properties. Although numerous classes of quinazolines have been conventionally synthesized, their syntheses have been suffered due to the multiple steps that sometimes have described in their preparation and also their chemical transformations that have been taken hours or even days to be completed. However, microwave energy can offer numerous benefits for performing synthesis of organic compounds including reduced pollution, increased reaction rates, yield enhancements, and cleaner chemistries.

RESULTS

Synthesis of a series of triazoloquinazolinones and benzimidazoquinazolinones has been achieved under microwave irradiation. The products were obtained in nearly quantitative yields within few minutes during the reaction of aromatic aldehydes with 5-amino-1(H)-1,2,4-triazole (or 2-aminobenzimidazole) and dimedone in DMF.

CONCLUSION

Microwave irradiation can be used as a facile and general method for the construction of a wide variety of triazoloquinazolinones and benzimidazoquinazolinones. The reaction involves a three component condensation (with potential for combinatorial work) being carried out with almost productive yields by microwave irradiation and considerably shortened reaction time.

Organic azides: an exploding diversity of a unique class of compounds

Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aubé rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.

Studies on Uracils: Synthesis of Tetrazolo[4’,5':1,6]pyrido[2,3-d]pyrimidines by the Action of Cyano Stabilised Carbanions on 6-Azido-5-formyluracils

6-Azido-5-formyluracils 2 undergo base catalysed condensation with cyanocarbanions to yield tetrazolo[4’,5':1,6]-pyrido[2,3- d]pyrimidines 4 in good yields.