One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

•  5) using seven benzaldehydes 1, two isonitriles 4, and allylamine hydrochloride (2) with trimethylsilyl azide (3) for the Ugi-azide reaction. The N-alkylations were conducted using benzyl bromide and iodomethane, respectively. The final products 8b–j were obtained in 66–74% yields. To evaluate the

Strategies in the synthesis of dibenzo[b,f]heteropines

• David I. H. Maier,
• Barend C. B. Bezuidenhoudt and
• Charlene Marais

Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51

• first reported synthesis of imipramine (3) by Schindler and Häfliger [76] proceeded by alkylation of 2a by alkyl halides. Selected N-alkylations of 1a and 2a are included in Scheme 33. N-Allylation of 1a or 2a with allyl bromide (143) can be achieved by a base-promoted substitution reaction (Scheme 33A

Synthesis of dihydroquinazolines from 2-aminobenzylamine: N³-aryl derivatives with electron-withdrawing groups

• Nadia Gruber,
• Jimena E. Díaz and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2018, 14, 2510–2519, doi:10.3762/bjoc.14.227

• moiety. Our approach involves two selective functionalizations of 2-ABA followed by a ring-closure step. Some selective N-acylations and N-alkylations of this precursor had been described in the literature, involving in many cases additional protection and deprotection steps or affording modest yields

Mechanochemical N-alkylation of imides

• Anamarija Briš,
• Mateja Đud and
• Davor Margetić

Beilstein J. Org. Chem. 2017, 13, 1745–1752, doi:10.3762/bjoc.13.169

• of imides with alkyl halogenides, and the results are presented in this paper. Until now, ball milling N-alkylations of ureas [15], hydrazones [16], imines [17][18], pyridines [19], pyrimidines [20], imidazoles [21], secondary amines [22], as well as allylic alkylation reactions [23] were reported in

Syntheses of 3,4- and 1,4-dihydroquinazolines from 2-aminobenzylamine

• Jimena E. Díaz,
• Silvia Ranieri,
• Nadia Gruber and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2017, 13, 1470–1477, doi:10.3762/bjoc.13.145

• -assisted ring closure of the corresponding aminoamides promoted by ethyl polyphosphate (PPE). Keywords: dihydroquinazolines; microwaves; N-acylations; N-alkylations; PPE; Introduction Nitrogen heterocycles are part of many drugs and represent structures with wide therapeutic potential. Therefore, much

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• . Absorption spectrum was recorded at 10 μM. Emission spectrum was recorded at 100 nM, with excitation at 318 nm. Proposed retrosynthesis scheme to access N-isopropyl-THQ 2. Synthesis of THQ 3 by initial N-alkylations, followed by PPA-mediated cyclisation. Bromination of 3 and attempted halogen exchange of the

Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold

• Nikolay T. Tzvetkov,
• Harald Euler and
• Christa E. Müller

Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181

• the imidazo[5,1-c][1,2,4]triazine frameworks starting from the commercially available 5,5-dimethylhydantoin 6. The reaction sequence involves successive N-alkylations of the corresponding hydantoin, followed by C5-thionation and an intramolecular heterocondensation reaction with hydrazine hydrate as a

Gold(I)-catalyzed synthesis of γ-vinylbutyrolactones by intramolecular oxaallylic alkylation with alcohols

• Michel Chiarucci,
• Mirko Locritani,
• Gianpiero Cera and
• Marco Bandini

Beilstein J. Org. Chem. 2011, 7, 1198–1204, doi:10.3762/bjoc.7.139

• comparable yield (72%, entry 1) and similar diastereomeric ratio. Here, although the impact of the C─C double bond configuration on the stereochemical outcome of SN2′-type gold-catalyzed intramolecular O- [45] and N-alkylations [37][46] with allylic alcohols was demonstrated, we consider it likely that an