Dihydro derivatives of pyrazolo[3,4-b]pyridine-, pyrazolo[1,5-a]pyrimidine-, and [1,2,4]triazolo[ 1,5-a]pyrimidinecarboxylates have been prepared by cyclocondensation of beta-aroylacrylates with 5-aminopyrazoles and 3-amino-1,2,4-triazole. Heating dihydro[1,2,4]triazolo[1,5-a]pyrimidine-7-carboxylates with hydrazine hydrate led to recyclization of the pyrimidine ring to form 6-arylpyridazin-3(2H)-ones.
C7‐Functionalization of Indoles via Organocatalytic Enantioselective Friedel‐Crafts Alkylation of 4‐Amino‐ indoles with 2‐Butene‐1,4‐diones and 3‐Aroylacrylates
作者:Tongkun Huang、Yunlong Zhao、Shanshui Meng、Albert S. C. Chan、Junling Zhao
DOI:10.1002/adsc.201900377
日期:2019.8.5
An efficient protocol for the enantioselective C7 Friedel‐Crafts alkylation between 4‐aminoindoles and 2‐butene‐1,4‐diones or 3‐aroylacrylates was reported. This process was catalyzed by a chiral phosphoric acid, affording the corresponding 1,4‐disubstituted indoles in moderate to high yields with good to high enantioselectivities. This reaction could be performed on a gram scale without loss of efficiency
Chiral N-heterocyclic carbene-catalyzed generation of ester enolate equivalents from α,β-unsaturated aldehydes for enantioselective Diels–Alder reactions
作者:Juthanat Kaeobamrung、Marisa C. Kozlowski、Jeffrey W. Bode
DOI:10.1073/pnas.1007469107
日期:2010.11.30
The catalytic generation of chiral ester enolate equivalents from alpha,beta-unsaturated aldehydes with chiral N-hetereocyclic carbene catalysts makes possible highly enantioselective hetero-Diels-Alder reactions. The reactions proceed under simple, mild conditions with both aliphatic and aromatic substituted enals as substrates. Previous attempts to employ these starting materials as enolate precursors
has been accomplished in the presence of a chiral N,N′‐dioxide/[Sc(OTf)3] complex (0.5–2 mol %), delivering the desired vicinal anti‐α‐iodo‐β‐amino carbonyl compounds regioselectively in high yields (up to 97 %) and with excellent diastereoselectivities (>99:1 d.r.) and enantioselectivities (up to 99 % ee). Enantiopure syn‐α‐iodo‐β‐amino products could also be obtained from the isomerization of particular
Structure-Activity Relationship, Cytotoxicity and Mode of Action of 2-Ester-substituted 1,5-Benzothiazepines as Potent Antifungal Agents
作者:Wang Kang、Xingqiong Du、Lanzhi Wang、Lijuan Hu、Yuhuan Dong、Yanqing Bian、Yuan Li
DOI:10.1002/cjoc.201300316
日期:2013.10
were further studied by evaluating their cytotoxicity and mode of action (for 7a). The results showed that compounds 7a and 7b were relatively safe for BV2 cells, but compound 7a interfered with Cryptococcus neoformans cell wall integrity by increasing the chitinase activity. Therefore, compound 7a was considered safe as an antifungal agent for animal cells.
α-Functionalization of 2-Vinylpyridines via a Chiral Phosphine Catalyzed Enantioselective Cross Rauhut–Currier Reaction
作者:Cong Qin、Yonghai Liu、Yang Yu、Yiwei Fu、Hao Li、Wei Wang
DOI:10.1021/acs.orglett.8b00008
日期:2018.3.2
Herein, 2-vinylpyridines as a newtype of electron-poor system for the asymmetric cross Rauhut–Currier reaction are reported. 2-Vinylpyridines are chemo- and enantioselectively activated by a newly designed chiral phosphine catalyst. The newreaction provides a powerful synthetic tool for accessing structurally diverse, highly valued chiral pyridine building blocks in good yields and with high enantioselectivities