scholarly journals An Efficient Carbonized Sugar Catalyzed Entry to 7,8-dihydro-2H-Chromen-5(6H)-ones

2021 ◽  
Vol 13 (3) ◽  
pp. 971-978
Author(s):  
T. Siddiqui ◽  
P. Kulkarni ◽  
G. Tiwari ◽  
Z. Pudukulathan
Keyword(s):  
Acetic Acid ◽  
Visible Light ◽  
Widespread Application ◽  
Mild Conditions ◽  
Excellent Yield

The present paper describes a facile entry to various substituted 7,8-dihydro-2H-chromen-5-ones under neat conditions using simple carbonized sugar as a catalyst. The reaction was promoted by visible light under neat or in acetic acid as a solvent with a catalyst to afford the desired products in good to excellent yield. Mild conditions coupled with ease of operation make the protocol synthetically attractive and may find widespread application for the synthesis of chromenone scaffold.

Visible-Light-Induced Aerobic Oxidation of Benzylic C(sp3)–H of Alkylarenes Promoted by DDQ, tert-Butyl Nitrite, and Acetic Acid

Synlett ◽  
2018 ◽  
Vol 30 (02) ◽  
pp. 218-224 ◽  
Author(s):  
Zhenlu Shen ◽  
Decheng Pan ◽  
Yiqing Wang ◽  
Meichao Li ◽  
Xinquan Hu ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Visible Light ◽  
Aerobic Oxidation ◽  
Catalyst Loading ◽  
Thermal Methods ◽  
Oxidation Method ◽  
Tert Butyl ◽  
Mild Conditions ◽  
Low Catalyst Loading ◽  
Visible Light Photocatalytic

A visible-light photocatalytic aerobic oxidation of benzylic C(sp3)–H bonds proceeded in the presence of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, tert-butyl nitrite, and acetic acid. Advantages of this aerobic oxidation method include its relatively mild conditions, the use of visible-light irradiation instead of conventional thermal methods, the use of a low catalyst loading, and the ability to oxidize a range of alkyl­arenes, including xanthenes, thioxanthenes, and 9,10-dihydroacridines, to the corresponding ketones in excellent yields.

An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

1991 ◽  
Vol 56 (12) ◽  
pp. 2917-2935 ◽  
Author(s):  
Eva Klinotová ◽  
Václav Křeček ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Acetic Anhydride ◽  
Spectral Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Condensation Products ◽  
Unsaturated Lactones ◽  
C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

Enantioselective Radical Functionalization of Imines and Iminium Intermediates via Visible Light Photoredox Catalysis

Synthesis ◽  
2020 ◽  
Author(s):  
Jia-Jia Zhao ◽  
Hong-Hao Zhang ◽  
Shouyun Yu
Keyword(s):  
Visible Light ◽  
Asymmetric Synthesis ◽  
Carbonyl Compounds ◽  
Asymmetric Reduction ◽  
Chemical Transformations ◽  
Photoredox Catalysis ◽  
Radical Coupling ◽  
Mild Conditions ◽  
Iminium Ions ◽  
Radical Functionalization

Visible light photoredox catalysis has recently emerged as a powerful tool for the development of new and valuable chemical transformations under mild conditions. Visible-light promoted enantioselective radical transformations of imines and iminium intermediates provide new opportunities for the asymmetric synthesis of amines and asymmetric β-functionalization of unsaturated carbonyl compounds. In this review, the advance in the catalytic asymmetric radical functionalization of imines, as well as iminium intermediates, are summarized. 1 Introduction 2 The enantioselective radical functionalization of imines 2.1 Asymmetric reduction 2.2 Asymmetric cyclization 2.3 Asymmetric addition 2.4 Asymmetric radical coupling 3 The enantioselective radical functionalization of iminium ions 3.1 Asymmetric radical alkylation 3.2 Asymmetric radical acylation 4 Conclusion

Visible-Light-Mediated Tandem Sulfonylation/Cyclization of Vinyl Azides with Sulfonyl Hydrazines for the Synthesis of 6-(Sulfonylmethyl)phenanthridines under Mild Conditions

Synlett ◽  
2019 ◽  
Vol 30 (08) ◽  
pp. 955-960 ◽  
Author(s):  
Liu-Liang Mao ◽  
Li-Xia Quan ◽  
Xian-Hong Zhu ◽  
Cong-Bin Ji ◽  
An-Xi Zhou ◽  
...  
Keyword(s):  
Visible Light ◽  
Mild Conditions ◽  
Simple Strategy ◽  
Vinyl Azides

A visible-light-mediated tandem sulfonylation/cyclization of vinyl azides with sulfonyl hydrazines was developed that provides an efficient and simple strategy for the synthesis of valuable 6-(sulfonylmethyl)phenanthridines with a broad substrate scope and satisfactory yields under mild conditions.

Visible light-photocatalysed carbazole synthesis via a formal (4+2) cycloaddition of indole-derived bromides and alkynes

2016 ◽  
Vol 52 (29) ◽  
pp. 5128-5131 ◽  
Author(s):  
Zhi-Guang Yuan ◽  
Qiang Wang ◽  
Ang Zheng ◽  
Kai Zhang ◽  
Liang-Qiu Lu ◽  
...  
Keyword(s):  
Visible Light ◽  
Mild Conditions ◽  
Wide Range

We have developed an unprecedented route to carbazole by a visible light-photocatalysed formal (4+2) cycloaddition of indole-derived bromides and alkynes. Using this method, a wide range of highly functionalised carbazoles were produced in good yields under mild conditions.

Photocatalytic degradation of acetic acid in the presence of visible light-active TiO 2 -reduced graphene oxide photocatalysts

2017 ◽  
Vol 280 ◽  
pp. 108-113 ◽  
Author(s):  
A.W. Morawski ◽  
E. Kusiak-Nejman ◽  
A. Wanag ◽  
J. Kapica-Kozar ◽  
R.J. Wróbel ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Graphene Oxide ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene ◽  
Visible Light Active

Visible-light-assisted efficient removal of sulfur from high sulfur coal under mild conditions

2021 ◽  
pp. 1-15
Author(s):  
Gongcheng Sun ◽  
Mei Li ◽  
Xueyun Cheng ◽  
Ning Ding ◽  
Jingsong Yue ◽  
...  
Keyword(s):  
Visible Light ◽  
Efficient Removal ◽  
Mild Conditions

Organic Sulfinic Acids and Salts in Visible Light-Induced Reactions

Synthesis ◽  
2021 ◽  
Author(s):  
Zheng Lu ◽  
Mingzhou Shang ◽  
Hongjian Lu
Keyword(s):  
Visible Light ◽  
Reaction Mechanisms ◽  
Review Article ◽  
Reaction Type ◽  
Mild Conditions ◽  
Sulfinic Acids ◽  
Sulfur Containing

Sulfinic acids and their salts are a useful source of sulfur-containing structures. Photocatalysis of these compounds with visible light enables chemists to achieve various transformations under mild conditions. This review article summarizes visible light-induced reactions of sulfinic acids and their salts. This article is organized by reaction type and brief discussions on plausible reaction mechanisms for typical transformations are presented.

Sign in / Sign up

Export Citation Format

Share Document