β-Lactamase inhibition profile of new amidine-substituted diazabicyclooctanes

• Zafar Iqbal,
• Lijuan Zhai,
• Yuanyu Gao,
• Dong Tang,
• Xueqin Ma,
• Jinbo Ji,
• Jian Sun,
• Jingwen Ji,
• Yuanbai Liu,
• Rui Jiang,
• Yangxiu Mu,
• Lili He,
• Haikang Yang and
• Zhixiang Yang

Beilstein J. Org. Chem. 2021, 17, 711–718, doi:10.3762/bjoc.17.60

• , Jinfeng District, Yinchuan, Ningxia 750002, P.R. China College of Pharmacy, Ningxia Medical University, Shengli Street, Xingqing District, Yinchuan, Ningxia 750004, P.R. China 10.3762/bjoc.17.60 Abstract The diazabicyclooctane (DBO) scaffold is the backbone of non-β-lactam-based second generation β

• MIC from <0.125 mg/L to 2 mg/L, and is comparable to avibactam against both E. coli strains with a MIC value of <0.125 mg/L. Keywords: amidine; antibacterial activity; β-lactamase inhibitors; diazabicyclooctane; synthesis; Introduction Survival stress posed by antimicrobial agents triggers multiple

• in Escherichia coli clinical isolates [14][15]. The diazabicyclooctane (DBO) [16] ring suggested as an alternative to the β-lactam ring [17] by the Hoechst researchers [16] could not prove its antibacterial strength in early experiments rather it showed β-lactamase inhibition activity. This discovery

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Synthesis of 2,3-dihydronaphtho[2,3-d][1,3]thiazole-4,9-diones and 2,3-dihydroanthra[2,3-d][1,3]thiazole-4,11-diones and novel ring contraction and fusion reaction of 3H-spiro[1,3-thiazole-2,1'-cyclohexanes] into 2,3,4,5-tetrahydro-1H-carbazole-6,11-diones

• Lidia S. Konstantinova,
• Kirill A. Lysov,
• Ljudmila I. Souvorova and
• Oleg A. Rakitin

Beilstein J. Org. Chem. 2013, 9, 577–584, doi:10.3762/bjoc.9.62

• -[butyl(methyl)amino]naphthoquinone 3a with sulfur monochloride and tertiary amines [N-ethyldiisopropylamine (Hünig’s base) and 1,4-diazabicyclooctane (DABCO)]. Treatment of naphthoquinone 3a with S2Cl2 (9 equiv) and Hünig’s base (5 equiv) in THF at 0 °C for 72 h with subsequent heating under reflux for 2

• with S2Cl2 provides a short and convenient route to 2,3-dihydronaphtho[2,3-d][1,3]thiazole-4,9-diones and 2,3-dihydroanthra[2,3-d][1,3]thiazole-4,11-diones, which are of special interest as biologically active compounds. A striking difference in the influence of 1,4-diazabicyclooctane and N

• -diones 1 and 3-methyl-2,3-dihydroanthra[2,3-d][1,3]thiazole-4,11-diones 2: Sulfur monochloride (0.40 mL, 5.00 mmol) was added dropwise to a stirred solution of 1,4-diazabicyclooctane (1.12 g, 10.00 mmol) in chlorobenzene (80 mL) at −30 °C. The reaction mixture was stirred for 1 h at room temperature, and