Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• structure and reactivity of the obtained macrocycle are outlined. Keywords: amidrazones; hexaazamacrocycles; pyrazolo[3,4-d]pyrimidines; ring contraction; self-assembly; Introduction The chemistry of polyazamacrocycles (PAMs) is currently one of the most rapidly developing areas of heterocyclic chemistry

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• extensively employed as useful synthons in designing and constructing a plethora of fused pyrazoloazines of potential synthetic and medicinal interest viz pyrazolo[3,4-b]pyridines 7 [18], pyrazolo[1,5-a]pyrimidines 8 [19], pyrazolo[3,4-d]pyrimidines 9 [20][21], pyrazolo[3,4-b]pyrazines 10 [22], pyrazolo[5,1-c

• equivalent of isoflavones 178 in the presence of 3 equivalents of sodium methoxide in methanol (Scheme 50). The method has the merits of being simple in operation with mild reaction conditions and good yields of fused pyrazole derivatives. Synthesis of pyrazolo[3,4-d]pyrimidines A diversity of biological

• effects is associated with pyrazolo[3,4-d]pyrimidines. They are known to exhibit antiviral [111][112], pesticidal [113], anti-inflammatory [114], antimicrobial [115][116][117], antileukemic [118], antitumor [114][119][120], pan-RAF inhibiting [121], tyrosine kinase RET inhibiting [122], CNS [123

A convenient four-component one-pot strategy toward the synthesis of pyrazolo[3,4-d]pyrimidines

• Mingxing Liu,
• Jiarong Li,
• Hongxin Chai,
• Kai Zhang,
• Deli Yang,
• Qi Zhang and
• Daxin Shi

Beilstein J. Org. Chem. 2015, 11, 2125–2131, doi:10.3762/bjoc.11.229

• ]. For example, ibrutinib, sildenafil, allopurinol and zaleplon are famous pyrazolopyrimidine drugs. Because of the importance of pyrazolo[3,4-d]pyrimidines, many methods for the synthesis of pyrazolo[3,4-d]pyrimidines have been explored. Some examples include the condensation of 5-aminopyrazole-4

• ). But when benzaldehyde was switched to anisaldehyde, the expected product was not obtained and pyrazolo[3,4-d]pyrimidines was isolated (Scheme 1B). Inspired by this phenomenon, we conducted detailed studies and found a new convenient synthesis of pyrazolo[3,4-d]pyrimidines. To the best of our knowledge

• , this is a novel methodology for the synthesis of pyrazolo[3,4-d]pyrimidines by the reaction of hydrazines, methylenemalononitriles, aldehydes and alcohols. During the preparation of this manuscript, Liu et al. reported the synthesis of pyrazolo[3,4-d]pyrimidines from 5-aminopyrazole-4-carbonitrile [48

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• -dielectrophiles has been extensively used for the preparation of bicyclic nitrogen heterocycles, especially in the preparation of condensed heterocycles such as pyrazolo[3,4-d]pyrimidines, pyrazolo[3,4-b]pyridines, imidazopyrazoles etc. In view of significant interest in the synthesis of these heterocyclics, we

One-pot synthesis of novel 1H-pyrimido[4,5-c][1,2]diazepines and pyrazolo[3,4-d]pyrimidines

• Dipak Prajapati,
• Partha P. Baruah,
• Baikuntha J. Gogoi and
• Jagir S. Sandhu

Beilstein J. Org. Chem. 2006, 2, No. 5, doi:10.1186/1860-5397-2-5

• ]diazepines 3 & 4 and pyrazolo [3,4-d]pyrimidines 6 were regioselectively synthesised by the reaction of 1,3-dimethyl-6-hydrazinouracils 1 with various α,β-unsaturated compounds 2 and α-ketoalkynes 8 in excellent yields. Introduction The importance of uracil and its annelated substrates is well recognized by

• heteroannulation of uracils usually require either forcing conditions[16][17] or relatively longer synthetic pathways.[18] Also, pyrazolo [3,4-d]pyrimidines are a class of naturally occurring fused uracils that possess a wide range of biological activity.[19] Allopurinol (6-dehydroxy-pyrazolo [3,4-d]pyrimidine

• -unsaturated compounds and α-ketoalkynes, which give access to an efficient unprecedented one-pot synthesis of novel pyrimido [4,5-c][1,2]diazepine-6,8-diones 3 or 4 and pyrazolo [3,4-d]pyrimidines 6 in excellent yields. A previous synthesis of pyrimido [4,5-c][1,2]diazepines reported by Mallory et al.[25