14002-97-2Relevant academic research and scientific papers
Xanthan sulfuric acid: An efficient and recyclable solid acid catalyst for Pechmann condensation
Kuarm, B. Suresh,Madhav, J. Venu,Rajitha
, p. 1770 - 1777 (2012)
In this report, substituted coumarins are formed via Pechmann condensation using various substituted phenols and ethyl acetoacetates in the presence of xanthan sulfuric acid as a solid acid catalyst under solvent-free conditions. This method is very simple, costeffective, and has shorter reaction times, and the catalyst could be reused. Copyright Taylor & Francis Group, LLC.
Scandium(III) triflate-catalyzed coumarin synthesis
Jung, Keumnyeo,Park, Yun-Jeong,Ryu, Jae-Sang
, p. 4395 - 4406 (2008)
Scandium(III) triflate is an excellent catalyst in the von Pechmann condensation. The solvent-free catalytic reactions proceed smoothly with a range of phenols and β-ketoesters in the presence of 10 mol% scandium(III) triflate at 80°C. This simple method affords various 4-substituted coumarins in good to excellent yield and is superior to the classical method in several aspects: solvent-free conditions, short reaction times, a decreased catalyst loading, a mild reaction temperature, and an easy workup. Copyright Taylor & Francis Group, LLC.
Synthes?s and character?zat?on of new tr?azole and coumar?n-derived heterocycl?c compounds part I
Gümrük?üo?lu, Nurhan,Imran, Muhammad,Iqbal, Inam
, p. 1097 - 1106 (2020/01/09)
Synthesis of ethyl ester of acetic acid containing 5-oxo-[1,2,4] triazole ring (2) was achieved by the condensation of 3-substituted-4-amino-1H-1,2,4-triazol-5(4H)-one (1) with ethyl bromoacetate in basic medium. Compound 2, was then further reacted with hydrazine hydrate to form acid hydrazide, which is 2-(4-amino-3-substituted-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)acetohydrazide (3). Compound 3 was later treated with three different diverse coumarin aldehydes (6, 12, 18) resulted in the formation of arylidene hydrazides as cis–trans conformers (7, 8, 13, 14, 19, 20). In conclusion, we synthesized 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-1,2,4-triazole-5-on and formylhydroxy-4-methylcoumarin derivatives, which have been characterized by, spectroscopic measurements (IR, 1H-NMR, 13C-NMR and elemental analysis).
Multi-component one-pot synthesis of novel coumarinyldihydropyridines under solvent free conditions
Bohra, Kapil,Sharma, Deepti,Kumar, Banty,Olsen, Carl E.,Parmar, Virinder S.,Prasad, Ashok K.
, p. 1885 - 1891 (2014/01/17)
A library of fourteen 4-coumarinyl-1,4-dihydropyridines (coumarinyl-1,4-DHP) has been synthesized under modified Hantzsch 1,4-dihydropyridine synthesis condition by the condensation of 4-formylcoumarin, alkyl acetoacetate and ammonium acetate in the presence of Ba(NO 3)2 as a catalyst in 58 to 82% yields. Standardization of reaction conditions revealed that 10 mol% of Ba(NO3)2 is enough for optimum yields. The developed methodology does not require the use of organic solvents and hence makes the process eco-friendly. The structure of all the coumarinyl-1,4-DHPs were unambiguously eastablished on the basis of IR, 1H, 13C NMR spectroscopy and HRMS data analysis.
13C Nuclear Magnetic Resonance Spectroscopy of 4-Methylcoumarins (4- Methyl-2H-1-benzopyran-2-ones)
Parmar, V. S.,Singh, S.,Boll, P. M.
, p. 430 - 433 (2007/10/02)
The 13C NMR spectra of 36 differently substituted 4-methylcoumarins (4-methyl-2H-1-benzopyran-2-ones) have been recorded.The effects of an alkyl side-chain at C-3 on the chemical shift values and that of a methoxy or an acetoxy group in place of a hydroxy group have been observed and rationalized.This study may be helpful in the structure elucidation of nei and natural 4-methylcoumarins. KEY WORDS 13C NMR chemical shifts 4-Methylcoumarins 4-Methyl-2H-1-benzopyran-2-ones.
