The Groebke–Blackburn–Bienaymé reaction in its maturity: innovation and improvements since its 21st birthday (2019–2023)

• Cristina Martini,
• Muhammad Idham Darussalam Mardjan and
• Andrea Basso

Beilstein J. Org. Chem. 2024, 20, 1839–1879, doi:10.3762/bjoc.20.162

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

• -arylations of unprotected primary diamines have not been systematically investigated yet. Regarding the last step of the sequence leading to compounds 1, our group has worked extensively on ring-closure reactions leading to nitrogen-containing heterocycles such as 5–8-membered cyclic amidines [81][82][83], N

Selective formation of a zwitterion adduct and bicarbonate salt in the efficient CO₂ fixation by N-benzyl cyclic guanidine under dry and wet conditions

• Yoshiaki Yoshida,
• Naoto Aoyagi and
• Takeshi Endo

Beilstein J. Org. Chem. 2018, 14, 2204–2211, doi:10.3762/bjoc.14.194

• ambient temperature and pressure [19][20][21][22]. Furthermore, cyclic amidines and guanidines, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), exhibited an excellent efficiency of CO2 capture and release [23][24][25][26][27][28][29][30][31][32][33]. 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

• effort has been devoted to the development of efficient, general and expeditious methods for their synthesis [1][2]. Cyclic amidines are compounds of interest due to their multiple pharmacological properties, some of which derive from their interaction with a specific receptor [3][4]. Six-membered

Microwave-assisted cyclizations promoted by polyphosphoric acid esters: a general method for 1-aryl-2-iminoazacycloalkanes

• Jimena E. Díaz,
• María C. Mollo and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2016, 12, 2026–2031, doi:10.3762/bjoc.12.190

• synthesis. Keywords: cyclic amidines; medium size heterocycles; microwaves; PPE; PPSE; Introduction The synthesis of new nitrogen heterocycles has a great interest in medicinal chemistry since they are part of many drugs and represent structures with a wide therapeutic potential [1][2]. 2

• -Iminoazacycloalkanes are cyclic amidines where the formally sp2 nitrogen is exocyclic. These compounds have been described as selective inhibitors of the inducible form of human nitric oxide synthase (iNOS), which catalyzes the reaction to form nitric oxide via the oxidation of L-arginine to L-citrulline [3][4][5][6

• of conventional heating [17]. In previous work, we reported the microwave-assisted synthesis of 5 to 8 membered cyclic amidines by cyclodehydration of N-aryl-N´-acyl-1,n-alkanediamines (n = 2–5) promoted by polyphosphoric acid (PPA) esters PPE and PPSE (Scheme 1, reaction 1) [41][42][43]. In this