Aminomethylation of cytisine by 3-hetaryl-7-hydroxycoumarins

8-Aminomethyl derivatives of 7-hydroxycoumarins were prepared by reaction of methylene-bis-cytisine and substituted 7-hydroxycoumarins. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 145–148, March–April, 2007.     

1,2,4-Thiadiazole derivatives of cytisine

Several new derivatives were prepared by reaction of 3-alkylthio-5-chloroacetamido-1,2,4-thiadiazoles with cytisine.Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 479–480, November–December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

2-[6-Alkyl-3-hetaryl-4-oxo-9,10-dihydro-4H,8H-chromeno-[8,7-<Emphasis Type="Italic">e</Emphasis>][1,3]oxazin-9-yl]acetic acids

The interaction has been studied of a series of substituted 3-hetaryl-7-hydroxychromones with amino acids and formaldehyde (reactants ratio 1: 1: 2 respectively). In the case of glycine and Het = 3-isoxazolyl the product of aminomethylation at position 8 of the chromone was obtained, and with other Het (including Het = 4-phenyl-1,2,4-triazol-3-yl) 2-[6-alkyl-3-hetaryl-4-oxo-9,10-dihydro-4H,8H-chromeno[8,7-e][1,3]-oxazin-9-yl]acetic acids were formed. With β-alanine and Het = 4-phenyl-1,2,4-triazol-3-yl the corresponding β-substituted propionic acid was synthesized, but proline did not participate in the reaction, leading to bis(6-ethyl-3-hetaryl-7-hydroxychromon-8-yl)methane. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 683–689, May, 2007.     

Thiazole and benzothiazole derivatives of cytisine

Several new derivatives were prepared by reacting N-1(5-R-thiazol-2-yl)-2-chloroacetamides and N-1(6-R-benzothiazol-2-yl)chloroacetamides with cytisine. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 379–380, July–August, 2006.     

Synthesis of cytisine derivatives of coumarins

New substituted 4-chloromethylcoumarins that were used as alkylating agents to modify cytisine were synthesized by Pechmann condensation. A series of 4-(12-cytisylmethyl)coumarins containing pharmacophores of the natural heterocycles coumarin and cytisine in a single molecule was prepared. The alkylation gave the best results if diisopropylethylamine was used as the base. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 485–488, September–October, 2007.     

Novel synthesis of 2-amino-3-hetaryl-4(5H)-oxothiophenes

3-Cyano-3-hetaryl-2-oxopropyl thioacetates were obtained by the acylation of hetarylacetonitriles with acetylmercaptoacetyl chloride. Their reaction with amines led to the formation of 2-amino-3-hetaryl-4(H)-oxothiophenes. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 680–685, May, 2006.     

Effects of polar protic solvents on dual emissions of 3-hydroxychromones

3-Hydroxychromones (3HC), exhibit dual emissions highly sensitive to solvent properties due to excited state intramolecular proton transfer (ESIPT). Therefore, 3HCs find wide applications as fluorescence probes in biological systems. Here, it is particularly important to understand the fluorescence behaviour of 3HCs in polar environments. Herein, we studied 3-hydroxyflavone, 2-(2-furyl)-3-hydroxychromone and 2-(2-benzofuryl)-3-hydroxychromone in high polarity solvents characterized by different H-bond donor abilities, donor concentrations and acceptor abilities. Our results show that the dual emissions of the dyes are insensitive to solvent basicity but strongly depend on the two other parameters. Moreover, furyl-and benzofuryl-substituted dyes were significantly more sensitive than the 3-hydroxyflavone to H-bond donor ability, while all three dyes showed roughly equivalent high sensitivity to H-bond donor concentration. These results can be explained by different mechanisms. Thus, the sensitivity of all three dyes to increasing concentrations of H-bond donors probably results from increase in the population of solvated dye with disrupted intramolecular H-bonds. Meantime, the sensitivity to H-bond donor ability of the solvent, observed mainly with furyl and benzofuryl dyes, is probably related to the strength of the H-bonds between the solvent and the 4-carbonyl group of the dye with intact intramolecular H-bonds. The present results provide new insights for further applications of 3HC derivatives as environment-sensitive probes and labels of biological molecules.     

Chemical modification of plant alkaloids. I. Aminomethylation of barbituric acid derivatives by cytisine

Reaction of cytisine with 1-mono- and 1,3-disubstituted 5-arylmethylbarbituric acids in the presence of formaldehyde results in aminomethylation of C-5 to form the corresponding 5-cytisylmethylbarbituric acids. The structures of the products are found using PMR spectroscopy and mass spectrometry. 1-Phenyl-5-(2,4-dimethoxybenzyl)-5-cytisylmethylbarbituric acid is obtained as a mixture of two steroisomers in an approximately 21 ratio.I. I. Mechnikov St. Petersburg State Medical Academy, 195067, St. Petersburg, Piskarevskii pr., 47; 2) ZAO Interbioscreen, 142432, Chernogolovka, Moscow District, Institutskii pr. 8. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 152–156, March–April, 2000.     

Cu‐Catalyzed Cross‐Dehydrogenative ortho‐Aminomethylation of Phenols

A highly selective Cu^II‐catalyzed cross‐dehydrogenative ortho‐aminomethylation of phenols with aniline derivatives is described. The corresponding C(sp²)?C(sp³) coupling products were obtained in moderate to excellent yields under mild reaction conditions and with a broad substrate scope. A radical mechanism is proposed.     

Reaction of cytisine with formalin

The reaction of cytisine with formalin in various solvents was studied. Methylene-bis-cytisine was produced in addition to the expected N-methylolcytisine in all solvents except acetone, in which N-(3-oxobutyl)cytisine was produced. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 579–580, November–December, 2006.     

间硝基苯甲醛或间氯苯甲醛与芳香胺和芳香酮的Mannich反应

间硝基苯甲醛或间氯苯甲醛与芳香胺和芳香酮在20~25℃和催化量的浓盐酸催化下能直接进行Mannich反应, 用一步合成法合成15个1-芳基-3-芳胺基(3-硝基苯基)丙酮。产率为68~87%。产物结构经元素分析, IR, ^1H NMR, MS鉴定。本文还讨论了反应的适宜条件。     

7-羟基-3-乙酰基香豆素曼尼希碱衍生物的合成及抗血小板聚集活性

以间苯二酚为起始原料,经Vilsmeier-Haack反应、Knoevenagel反应及Mannich反应得到中间体7-羟基-3-乙酰基香豆素曼尼希碱,再将其酮羰基肟化得到目标化合物.采用Born比浊法,以二磷酸腺苷(ADP)和花生四烯酸(AA)为诱导剂,阿司匹林为阳性对照,对5个化合物进行了的体外抗血小板聚集的活性试...     

芳香胺参加的Mannich反应——3-芳氨基-3-苯基-1-(4-溴苯基)丙酮的合成

文献报道过芳香胺与苯甲醛生成的Schiff碱可在少量相应的芳香胺盐酸盐或浓盐酸催化下制备Mannich碱(Ⅰ),所用的Schiff碱系事先合成,且产率较低(15-68.9％)。本文报导用4-溴苯乙酮、苯甲醛和芳香胺在少量浓盐酸催化下能直接发生Mannich反应,     

Synthesis and biological activity of N-benzyl derivatives of cytisine

The reductive alkylation of cytisine by various aromatic aldehydes was studied. Preliminary pharmacological investigations of the synthesized compounds were performed. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 373–378, July–August, 2006.     

Aminomethylation of organic halides promoted by zinc in protic medium

Organic halides undergo smooth aminomethylation by secondary amines and aqueous formaldehyde promoted by metallic zinc under copper(I) catalysis. Good to excellent yields are obtained with primary, secondary, and tertiary iodides, allylic, propargylic, and benzylic bromides and with α-bromoesters. In most cases, DMSO is the best solvent, but dioxane is preferable for some more reactive halides. Additional experiments with radical quenchers and promoters and the use of ‘radical clocks’ indicate a stepwise reaction mechanism initiated by the attack of an alkyl radical to iminium ion.     

Synthesis of N-substituted 9-[2-(3,4-methylenedioxyphenyl)-2-oxoethyl]-1,5-dinitro-7,8-benzo-3-azabicyclo[3.3.1]non-7-en-6-ones

Aminomethylation has been accomplished of the anionic Yanovskii adduct of 2,4-dinitronaphthol and 3,4-dimethylenedioxyacetophenone. The structure of the 3-substituted 9-[2-(3,4-methylenedioxyphenyl)-2-oxoethyl]-1,5-dinitro-7,8-benzo-3-azabicylo[3.3.1]non-7-en-6-one was determined by two-dimensional homo-and heteronuclear correlation spectroscopy. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1382–1389, September 2007.     

Synthesis of 5-amino-4-hetaryl-2,3-dihydro-1h-3-pyrrolones

2-Hetaryl-3-oxo-4-phthalimidobutyronitriles (and pentanonitriles) were obtained with high yields by C-acylation of hetarylacetonitriles with N-phthaloylglycine and -alanine chlorides respectively under the conditions of base catalysis. Hydrazinolysis of the phthaloyl protection in these compounds leads to the formation of 5-amino-4-hetaryl-2,3-dihydro-1H-3-pyrrolones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1783–1790, December, 2004.