多环麝香的分子结构和香气之间的关系

本文综述了多环麝香的当前进展,并提出了系统的分类方法。对各种多环麝香(茚满型,萘满型,异色满型,氢化引达省型,苊型)香味与分子结构之间关系的研究进行了总结,还作了比较。并描述了多环分子中环上取代基的性质,数量和位置对麝香香味的影响。     

Intramolecular Ketone-Olefin Radical Cyclization with Low-Valent Titanium Reagent: Synthesis of Benzopyrans

A novel protocol for intramolecular ketyl-olefin radical cyclization with low-valent titanium reagent is outlined. It allows the formation of the benzopyran nucleus from ortho-allyloxy propiophenones as the sole product in moderate yields via intramolecular radical cyclization.     

Novel isocyanide-based three-component reaction: a facile synthesis of substituted 1H-chromeno[2,3-d]pyrimidine-5-carboxamides

A mild and efficient method for the synthesis of 1H-chromeno[2,3-d]pyrimidine-5-carboxamide derivatives via a one-pot, three-component reaction of an isocyanide, barbituric acid, and a salicylaldehyde in the presence of acetic acid in ethanol/water mixture at 75 °C is reported. This high atom economy reaction led to the construction of one benzopyran ring, and one amide group in a single synthetic step.     

The first synthesis of 2-amino-1,4-dihydroquinolines

A versatile strategy is described for the synthesis of new 2-amino-1,4-dihydroquinolines. It involved a Knoevenagel condensation of N-protected-2-amino-5-bromobenzaldehyde with ethylcyanoacetate, followed by a cyclization and protection of the NH group to afford the key intermediates 7 or 19. Then various 1,4 addition reactions have been performed to introduce substituents on the upper part of the 2-amino-1,4-dihydroquinolines.     

An Efficient Synthesis of 3‐(1H‐Tetrazol‐5‐yl)coumarins (=3‐(1H‐Tetrazol‐5‐yl)‐2H‐1‐benzopyran‐2‐ones) via Domino Knoevenagel Condensation,Pinner Reaction,and 1,3‐Dipolar Cycloaddition in Water

A novel straightforward synthesis of 3‐(1H‐tetrazol‐5‐yl)coumarins (=3‐(1H‐tetrazol‐5‐yl)‐2H‐1‐benzopyran‐2‐ones) 6 via domino Knoevenagel condensation, Pinner reaction, and 1,3‐dipolar cycloaddition of substituted salicylaldehydes (=2‐hydroxybenzaldehydes), malononitrile (propanedinitrile), and sodium azide in H₂O is reported (Scheme 1 and Table 2). This general protocol provides a wide variety of 3‐(1H‐tetrazol‐5‐yl)coumarins in good yields under mild reaction conditions.     

Microwave assisted synthesis of indole-annulated dihydropyrano[3,4-c]chromene derivatives via hetero-Diels-Alder reaction

An efficient two-step synthesis of indole-annulated dihydropyrano[3,4-c]chromene derivatives is achieved via Knoevenagel condensation of O-propargylated salicylaldehyde derivatives with indolin-2-ones followed by a microwave-assisted intramolecular-hetero-Diels-Alder reaction of the resulting (Z)-3-(2-(prop-2-ynyloxy)benzylidene)indolin-2-ones in the presence of 20 mol % CuI in acetonitrile.     

Novel Synthesis of 2-Amino-3-ethoxycarbonyl Benzopyrans with Onium Salt as Soluble Support

Task specific onium salt has been presented as soluble support in the synthesis of benzopyrans in this paper. This method allows for results by far superior to those reported other soluble supports and allows for very easy purifications of reaction products.     

Eight New 2‐(2‐Phenylethyl)chromone (=2‐(2‐Phenylethyl)‐4H‐1‐benzopyran‐4‐one) Derivatives from Aquilaria malaccensis Agarwood

Eight new and eight known 2‐(2‐phenylethyl)chromone (=2‐(2‐phenylethyl)‐4H‐1‐benzopyran‐4‐one) derivatives, i.e., 1 – 8 and 9 – 16 , respectively, together with the two known sesquiterpenoids 17 and 18 were isolated from a 70% MeOH extract of Aquilaria malaccensis (AM) agarwood chips. Their structures were determined based on extensive spectroscopic analysis and comparison with reported data.     

Coordination ability of 3-pyridinyl coumarins with palladium(II) and platinum(II)

The coordination ability of two 3-pyridinyl coumarins with Pd(II) and Pt(II) both in solution and in solid state is elucidated by conventional and linear-polarized IR-spectroscopy of oriented colloid suspensions in nematic liquid crystal, ¹H- and ¹³C-NMR, UV-Vis spectroscopy, positive and negative ion mass spectrometry (ESI), HPLC tandem mass spectrometry (HPLC ESI MS/MS), TGV, and DSC methods. The four metal complexes are compared with free ligands. Density functional theory calculations are performed to obtain the electronic structure and vibrational properties of the compounds to support the experimental data.     

A Novel and Efficient Synthesis of 3‐[(4,5‐Dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐chromen‐2‐ones (=3‐[(4,5‐Dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐1‐benzopyran‐2‐ones)

An efficient one‐pot synthesis of 3‐[(4,5‐dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐chromen‐2‐one (=3‐[(4,5‐dihydro‐1H‐pyrrol‐3yl)carbonyl]‐2H‐1‐benzopyran‐2‐one) derivatives 4 by a four‐component reaction of a salicylaldehyde 1 , 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one, a benzylamine 2 , and a diaroylacetylene (=1,4‐diarylbut‐2‐yne‐1,4‐dione) 3 in EtOH is reported. This new protocol has the advantages of high yields (Table), and convenient operation. The structures of these coumarin (=2H‐1‐benzopyran‐2‐one) derivatives, which are important compounds in organic chemistry, were confirmed spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2).