Facile synthesis of 1-alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications

• Mahesh K. Lakshman,
• Manish K. Singh,
• Mukesh Kumar,
• Raghu Ram Chamala,
• Vijayender R. Yedulla,
• Domenick Wagner,
• Evan Leung,
• Lijia Yang,
• Asha Matin and
• Sadia Ahmad

Beilstein J. Org. Chem. 2014, 10, 1919–1932, doi:10.3762/bjoc.10.200

• appeared implausible on the basis of prior observations, where no reaction of BOP with the free hydroxy groups of nucleosides was observed [23][25]. Our recent work on a two-step one-pot etherification of purine nucleosides, quinazoline, and pyrimidines, had led some interesting preliminary observations

Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles

• Zong Guan,
• Jan C. Namyslo,
• Martin H. H. Drafz,
• Martin Nieger and
• Andreas Schmidt

Beilstein J. Org. Chem. 2014, 10, 832–840, doi:10.3762/bjoc.10.79

• . Keywords: E/Z isomerism; indazol-3-ylidene; mesomeric betaine; pyrazole; quinazoline; Rh complex; Introduction As a result of their biochemical and pharmacological significance, there has been a considerably growing interest in indazoles in recent years, which is reflected in several book chapters and

• . The dihedral angle C11–C12–C17–N18 (crystallographic numbering) was determined to be 0.5(2)°. This six-membered ring is almost perpendicularly twisted in relation to the quinazoline ring [N1–C10–C11–C12 = −92.65(17)°]. Conclusion The N-heterocyclic carbene of indazole, indazol-3-ylidene, displays a

Organobase-catalyzed three-component reactions for the synthesis of 4H-2-aminopyrans, condensed pyrans and polysubstituted benzenes

• Moustafa Sherief Moustafa,
• Saleh Mohammed Al-Mousawi,
• Maghraby Ali Selim,
• Ahmed Mohamed Mosallam and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2014, 10, 141–149, doi:10.3762/bjoc.10.11

• the products. Finally, these compounds were used for the efficient synthesis of 6-amino-5-cyanonicotinic acid ester derivatives 31a,b, ethyl 4-amino-5H-pyrano[2,3-d]pyrimidine-6-carboxylates 33a,b, 4-amino-6H-pyrrolo[3,4-g]quinazoline-9-carbonitrile 39, and 1,7-diamino-6-(N'-hydroxycarbamimidoyl)-3

• reacts with DMFDMA to form amidine 38, which undergoes cyclization in refluxing AcOH/NH4OAc to form the 1-amino-pyrrolo[3,4-f]quinazoline 39. We also found that 37a reacts with hydroxylamine hydrochloride in ethanolic sodium acetate solution to form isoindolone derivative 40 (Scheme 11 and Figure 13

• acid derivatives 31a,b, ethyl 4-amino-5H-pyrano[2,3-d]pyrimidine-6-carboxylates 33a,b, 4-amino-6H-pyrrolo[3,4-g]quinazoline-9-carbonitrile 39, and 1,7-diamino-6-(N'-hydroxycarbamimidoyl)-3-oxo-5-phenyl-3H-isoindole-4-carboxylate 40. X-ray crystal structure of 9. X-ray crystal structure of 13a. X-ray

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

Selective copper(II) acetate and potassium iodide catalyzed oxidation of aminals to dihydroquinazoline and quinazolinone alkaloids

• Matthew T. Richers,
• Chenfei Zhao and
• Daniel Seidel

Beilstein J. Org. Chem. 2013, 9, 1194–1201, doi:10.3762/bjoc.9.135

• to affect the selective oxidation of ring-fused aminals to dihydroquinazolines and quinazolinones, respectively. These methods enable the facile preparation of a number of quinazoline alkaloid natural products and their analogues. Keywords: aminal; copper; oxygen; tert-butylhydroperoxide

• ; quinazoline alkaloid; Introduction Quinazoline alkaloids are a class of naturally occurring compounds with a range of medicinal properties and have been indicated for use as bronchodilators, vasodilators, anti-inflammatory agents and acetylcholinesterase inhibitors [1][2][3][4][5]. Many of the plants these

• studied. A number of synthetic strategies have been employed to gain access to quinazoline alkaloids [5][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Perhaps the most common method involves the condensation of an ortho-aminobenzoic ester with a lactam promoted by phosphoryl chloride

3-Pyridylnitrene, 2- and 4-pyrimidinylcarbenes, 3-quinolylnitrenes, and 4-quinazolinylcarbenes. Interconversion, ring expansion to diazacycloheptatetraenes, ring opening to nitrile ylides, and ring contraction to cyanopyrroles and cyanoindoles

• Curt Wentrup,
• Nguyen Mong Lan,
• Adelheid Lukosch,
• Pawel Bednarek and
• David Kvaskoff

Beilstein J. Org. Chem. 2013, 9, 743–753, doi:10.3762/bjoc.9.84

• -tetrazolyl)pyrimidine (22) [36][37], 2-phenyl-4-(5-tetrazolyl)quinazoline (52) [23], and 5-phenyl-1,2,3-triazolo[1,5-a]quinazoline (53) [23] were prepared according to literature procedures. 4,6-Dimethyl-2-(5-tetrazolyl)pyrimidine (24) and 2,4-dimethyl-6-(5-tetrazolylpyrimidine) (23) were prepared from the

• , 80 mg; 45%), and indolo[3,2-b]quinoline (52 mg; 29%). FVT of 2-phenyl-4-(5-tetrazolyl)quinazoline (52): (a) A sample of 300 mg (1.10 mmol) was sublimed at 150 °C and pyrolysed at 600 °C/10−3–10−4 mbar in the course of 12 h. Chromatography yielded 178 mg (75%) of 3-cyano-2-phenylindole (48). (b) In

• similar experiments with FVT at 600–800 °C the product was isolated on a KBr window at 77 K for IR spectroscopy. In each case 3-cyano-2-phenylindole (48) was the exclusive product. Thermolysis of 2-phenyl-4-(5-tetrazolyl)quinazoline (52) in solution: (a) A solution of 250 mg (0.91 mmol) in 50 mL of xylene

Synthesis of SF₅-containing benzisoxazoles, quinolines, and quinazolines by the Davis reaction of nitro-(pentafluorosulfanyl)benzenes

• Petr Beier and
• Tereza Pastýříková

Beilstein J. Org. Chem. 2013, 9, 411–416, doi:10.3762/bjoc.9.43

• CAN using modified literature conditions (Scheme 3) [32]. Similarly, aminoketone 11a was condensed in good yield with cyclohexanone to provide quinoline 13 in good yield (Scheme 4). Finally, quinazoline 14 was synthesized by the reaction of aminoketone 11a with benzylamine in the presence of t-BuOOH

• Wipf and co-workers [29][30]. Synthesis of quinoline 12. Synthesis of quinoline 13. Synthesis of quinazoline 14. Synthesis of SF5-containing benzisoxazoles 7–9. Synthesis of ortho-aminobenzophenones 10 and 11. Supporting Information Supporting Information File 84: Experimental details

Features of the behavior of 4-amino-5-carboxamido-1,2,3-triazole in multicomponent heterocyclizations with carbonyl compounds

• Eugene S. Gladkov,
• Katerina A. Gura,
• Svetlana M. Sirko,
• Sergey M. Desenko,
• Ulrich Groth and
• Valentin A. Chebanov

Beilstein J. Org. Chem. 2012, 8, 2100–2105, doi:10.3762/bjoc.8.236

• '-cyclopentane}-3-carboxamide (4a) or 5,6,7,8-tetrahydro-4H-spiro{[1,2,3]triazolo[5,1-b]quinazoline-9,1'-cyclohexane}-3-carboxamide (4b) under all the conditions tested. The best results were observed in the case of microwave-assisted synthesis in methanol at 120 °C. Spirocompound 4c may be obtained by a

• [1,2,3]triazolo[5,1-b]quinazoline-3-carboxamides 7 or 9 under all the reactions conditions studied; however, the ultrasound-assisted procedure is the method of choice for this heterocyclization. For all the MCRs studied, changes in the directions of the heterocyclizations were not observed when microwave

• . Multicomponent synthesis of 4,5,6,7,8,9-hexahydro[1,2,3]triazolo[5,1-b]quinazoline-3-carboxamides 4a–c, 7 and 9a–j. Supporting Information Supporting Information File 322: Experimental details and characterization data for all new compounds. Acknowledgments ESG is grateful for financial support to DAAD

Regioselectivity in the multicomponent reaction of 5-aminopyrazoles, cyclic 1,3-diketones and dimethylformamide dimethylacetal under controlled microwave heating

• Kamal Usef Sadek,
• Ramadan Ahmed Mekheimer,
• Tahany Mahmoud Mohamed,
• Moustafa Sherief Moustafa and
• Mohamed Hilmy Elnagdi

Beilstein J. Org. Chem. 2012, 8, 18–24, doi:10.3762/bjoc.8.3

• naturally occurring and synthetic compounds containing quinazoline derivatives are of considerable interest in fields related to the organic and medicinal chemistry of natural products [1][2]. The quinazoline ring system represents the core skeleton of an important class of heterocyclic compounds possessing

A new and facile synthetic approach to substituted 2-thioxoquinazolin-4-ones by the annulation of a pyrimidine derivative

• Nimalini D. Moirangthem and
• Warjeet S. Laitonjam

Beilstein J. Org. Chem. 2010, 6, 1056–1060, doi:10.3762/bjoc.6.120

• number of quinazoline derivatives, which contain the 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine structural moiety in their heterocyclic rings, possess a wide range of biological activities [6][7][8]. There are a number of synthetic methods available for the preparation of quinazolines [9]. The most

• the higher temperature and the acid produces the required quinazoline. To obtain the optimal conditions, a variety of catalysts were also investigated to detect the catalytic activities of different metal ions and acetate in the production of 2a (Table 2). It was found that NH4OAc/AcOH in ZnCl2 was

• system, resulted in a new method for the formation of quinazoline derivatives. Thus, the reaction of 5-ethoxymethylenepyrimidine-4,6-diones 1 with malononitrile and ethyl cyanoacetate gave 7-amino-2,3-dihydro-2-thioxo-1,3-diarylquinazolin-4(1H)-ones 2 and 7-hydroxy-2,3-dihydro-2-thioxo-1,3

Microwave assisted synthesis of triazoloquinazolinones and benzimidazoquinazolinones

• Aboul-Fetouh E. Mourad,
• Ashraf A. Aly,
• Hassan H. Farag and
• Eman A. Beshr

Beilstein J. Org. Chem. 2007, 3, No. 11, doi:10.1186/1860-5397-3-11

• ] anticancer, [5] anti-inflammatory, [6] anticonvulsant, [7] and antiproliferative activities as well as inhibitory effects for thymidylate synthase and poly-(ADP-ribose) polymerase (PARP). [8] An interesting method for quinazoline synthesis involved [5+1] annulation during the reaction of β-dicarbonyl