174790-35-3Relevant articles and documents
Synthesis of (5,6-dihydro-4h-pyrrolo[1,2-b]pyrazol-3-yl)methanamine
Bai, Zhong-Gang,Qi, Hui,Zhang, Qun-Zheng,Ma, Yu,Pan, Qing,Zhang, Xun-Li
, p. 1923 - 1930 (2017/10/24)
This short paper reports the development of a new method for the synthesis of (5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl)methanamine. Pyrazole was initially protected with an N-SEM protective group, followed by alkylation at C-5 position with 1-bromo-3-chloropropane. Following SEM deprotection, the intramolecular ring was closed and then a bromine atom (Br) was introduced with N-bromosuccinimide (NBS) by electrophilic aromatic substitution (SEAr), forming 3-bromo-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole. The Br group was subsequently converted into aldehyde group, then into oxime. The final step of hydrogenation resulted in the desired product. The overall yield through the 8-step reaction process was found to be 29.4%. The intermediates and final product were identified by HPLC-MS and 1H NMR. This development provides a novel synthetic route to the formation of 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole skeleton.
Dihydropyrrolo[1,2-b]pyrazoles: Withasomnine and related compounds
Galeta, Juraj,Tenora, Luká?,Man, Stanislav,Potá?ek, Milan
, p. 7139 - 7146 (2013/07/26)
In the paper we indicate the increasing importance of derivatives containing a dihydropyrrolo[1,2-b]pyrazole (DPP) core. We try to show our synthetic approach based on an improved Kulinkovich method as well as our new synthetic pathway. A complex methodology involving the preparation of substituted DPPs focuses on withasomnine and the synthesis of several structurally related compounds. The developed reaction protocols enable the preparation of the mentioned bicyclic system with broadly diverse substitution. Thus, we are able to prepare systems with aliphatic, aromatic, polyaromatic, heteroaromatic, TMS, and even adamantane substitution with known biologically active properties. The reaction protocol, consisting of two multi-step synthetic pathways, includes Sonogashira and Suzuki-Miyaura cross-coupling reactions, allenyl synthon formation, Kulinkovich cyclopropanation, ring transformations, and nonsymmetrical homoallenyl azines cycloadditions. Moreover, we prepared compounds with a resemblance to other bioactive species: fadrozole, nagstatine, an antitumor agent LY2109761 and a mixed lineage kinase 7 inhibitor DHP-2.
2-PYRIDYL CARBOXAMIDE-CONTAINING SPLEEN TYROSINE KINASE (SYK) INHIBITORS
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, (2013/04/24)
The invention provides certain 2-pyridyl carboxamide-containing compounds of the Formula (I) or pharmaceutically acceptable salts thereof, wherein A and B are as defined herein. The invention also provides pharmaceutical compositions comprising such compounds, and methods of using the compounds for treating diseases or conditions mediated by Spleen Tyrosine Kinase (Syk) kinase.