Simple and Convenient Methods for the Synthesis of Indolo[3,2-c]acridines

The reaction of 2,3,4,9-tetrahydro-1H-carbazol-1-ones with anthranilic acid in POCl₃ yielded 7-chloro-5,6-dihydro-13H-indolo[3,2-c]acridines, while the same on reaction with isatin under the Pfitzinger reaction condition yielded 5,6-dihydro-13H-indolo[3,2-c]acridine-7-carboxylic acids. The latter reaction was carried out in different basic condition, because of, NaOH yielded more yield instead of KOH. Both the obtained products were treated with Pd/C in diphenyl ether to yield 13H-Indolo[3,2-c]acridines.     

Facile synthetic route to benzo[c]chromenones and thieno[2,3-c]chromenones

Convenient two-step procedure for the synthesis of fused chromenone derivatives was developed. Reduction of the obtained in the Meerwein arylation reaction aryl- and thienylquinones allowed to construct 6H-benzo[c]chromene-6-ones and 4H-thieno[2,3-c]chromen-4-one in a more cost- and time-effective manner in comparison with already known methods. The obtained products have provided a new entry to chromenone derivatives.     

Modified Coumarins. I. Synthesis of 5-Phenyl-7H-furo[2, 3-g]chromen-7-ones and 9-Phenyl-7H-furo-[2, 3-f]chromen-7-ones

5-Phenyl-7H-furo[2,3-g]chromen-7-ones and 9-phenyl-7H-furo-[2,3-f]chromen-7-ones, new analogs of psoralen and allopsoralen, are synthesized from 7-hydroxy- and 5-hydroxy-4-phenylcoumarins     

Modified Coumarins. 8. Synthesis of Substituted 5-(4-Methoxyphenyl)-7H-furo[3,2-g]chromen-7-ones

The MacLeod method was used to synthesize a series of substituted 5-(4-methoxyphenyl)-7H-furo[3,2- g]chromen-7-ones, modified analogs of psoralen, from 7-hydroxy-4-(4-methoxyphenyl)coumarins.     

Convenient synthesis of linear 2H,6H-pyrano[3,2-g] chromenes from natural occurring compound; visnagin

Abstract

A simple and convenient rout for the synthesis of linear 2-imino-2H,6H-pyrano[3,2-g] chromen-6-ones and 2H,6H-pyrano[3,2-g]chromene-2,6-diones has been described starting from natural occurring furochromone; visnagin (1). Ring opening of 1 yielded 6-formyl-7-hydroxy-5-methoxy-2-methylchromone (2), which underwent reaction with different acetonitrile derivatives furnished 2-imino-2H,6H-pyrano[3,2-g] chromen-6-ones (5a–h). Acid hydrolysis of 5a–h led to the formation of 2H,6H-pyrano[3,2-g]chromene-2,6-diones (6a–h). Structures of the synthesized compounds were clarified based on their elemental analyses and spectral data. The entire target compounds were selected for in vitro anticancer activity against 60 human cancer cell lines at a single dose (10^?5 M) by the National Cancer Institute (NCI, Bethesda, USA).     

Synthesis of 6H-benzo[c]chromen-6-ones by cyclocondensation of 1,3-dicarbonyl compounds with 4-chloro-3-formylcoumarin

6H-benzo[c]chromen-6-ones were prepared by base mediated cyclocondensation of 1,3-dicarbonyl compounds with 4-chloro-3-formylcoumarin.     

Studies on Quinazolines. Part III. Synthesis of Some Fused-Ring Cationic and Mesoionic Derivatives of the 1,3-Thiazolo[3,2-c]quinazoline Ring System

4-Allylthio-2-arylquinazolines 4a–c undergo cyclization by action of bromine to furnish 5-aryl-3-bromomethyl-2,3-dihydrothiazolo[3,2-c]quinazolin-4-ium bromide 5a–c. Compounds 5a–c undergo ring opening by action of water under acid catalysis to afford the corresponding dibromide derivatives 6a–c. Bromination of 3-allyl-2-aryl-4(3H)quinazolinethiones 7a–c leads to 5-aryl-2-bromomethyl-2,3-dihydrothiazolo[3,2-c]quinazolin-4-ium bromides 8a–c. However, 5-aryl-1,3-thiazolo[3,2-c]quinazolinium-3-olate 10a–c were prepared by the cyclodehydration of the corresponding thioglycolic acids 9a–c with Ac₂O.     

One-pot synthesis of 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridines through a cascade Michael/cyclization reaction

In this paper, a straightforward and valid three-component Michael/cyclization reaction of (E)-1-methyl-3-(arylidene)piperidin-4-ones, 2-(sulfonyl)acetonitriles, and aromatic aldehydes was explored for the preparation of potentially biologically active 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridines under mild reaction conditions. More diverse 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridine derivatives were constructed in satisfactory yields (up to 97%). The chemical structure of newly synthesized 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridines were identified with ¹H-NMR, ¹³C-NMR, and mass spectrometry analysis. The recommendable method features a simple and direct workup, easy access to initial materials, high atom utilization efficiency, high final product yields, and a wide range of substrate adaptability.     

Efficient Synthesis and Fungicidal Activities of 2-Alkylthiobenzofuro[3,2-d]Pyrimidinones

2-Alkylthiobenzofuro[3,2-d]pyrimidinones 5 and 6 were synthesized by S-alkylation of 2,3-dihydro-2-thioxobenzofuro[3,2-d]pyrimidin-4(1H)-ones 4, which were obtained via aza-Wittig reaction of iminophosphorane 2 with CS₂ and further reaction of the product with various amines. Compounds 5 and 6 exhibited fungicidal activity. For example, compound 6a, which has a small N-substituted methyl group, showed the best inhibitive activity (91%) against Dothiorella gregaria at 50 mg/L.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis of hydroxy-6H-benzofuro[3,2-c] [1]benzopyran-6-ones

The Micheal addition of ethyl 2-methoxy-, 2,4-dimethoxy- and 2,5-dimethoxybenzoylacetates with benzoquinone leads to ethyl 2-(rnethoxy or dimethoxy phenyl)-5-hydroxybenzofuran 3-carboxylates. Treatment of the henzofuran derivatives with anhydrous pyridine hydrochloride at 190–195° leads to hydroxy-6H-henzofuro[3,2-c] [1]benzopyran-6-ones.     

Modified Coumarins. 7. Synthesis and Biological Activity of Mannich Bases of Substituted 7,8,9,10-Tetrahydrobenzo[c]chromen-6-ones

Condensation of 1- and 3-hydroxy-7,8,9,10-tetrahydrobenzo[c]chromen-6-ones with substituted 1,1- diaminomethanes produced Mannich bases containing a dialkylaminomethyl group in the 2- and 4-positions of 7,8,9,10-tetrahydrobenzo[c]chromen-6-one. Pharmacological screening of 2-chloro-3-hydroxy-4-(1- pyrrolidinylmethyl)-7,8,9,10-tetrahydro-6H-benzo[c]chromen-6-one in Wistar rats showed that it possesses low toxicity and acts as a stimulant of the central and peripheral nervous systems with indications of neuroleptic and tranquilizing activities.     

A Convenient Synthesis of Novel Functionalized Pyrimido[5′,4′:4,5]thieno[3,2-c]pyridazines and Related Fused Systems

Possible approaches to the synthesis of functionalized, pyrimido[5′,4′:4,5]thieno [3,2-c]pyridazines 2-18 , pyridazino[3′,4′:4,5]thieno[2,3-d]triazines 19, 20a,b and pyrido[3′,2′:4,5]thieno[3,2-c]pyridazines 22a,b are described. The sequence involves the heterocyclization of 6-amino-1,3-diphenyl-1,4-dihydrothieno[3,2-c]pyridazine-7-carboxamide (1) with appropriate reagents. The antimicrobial activity of some the newly synthesized compounds was examined. All tested compounds proved to be active as antibacterial and antifungal agents.     

Expeditious entry to novel 2-methylene-2,3-dihydrofuro[3,2-c] chromen-2-ones from 6-chloro-4-hydroxychromen-2-one and propargylic alcohols

A catalytic system consisting of the ruthenium(II) complex [Ru(η3-2-C3H4Me)(CO)(dppf)][SbF6] (dppf=1,1'-bis(diphenylphosphino)ferrocene) and trifluoroacetic acid has been used to promote the coupling of secondary propargylic alcohols with 6-chloro-4-hydroxychromen-2-one. The reactions afforded unusual 2-methylene-2,3-dihydrofuro[3,2-c]chromen-2-ones in good yields.     

Synthesis of Novel 1,2,3-Triazole-dihydro[3,2-c]chromenones as Acetylcholinesterase Inhibitors

A novel series of 1,2,3-triazole-dihydro[3,2-c]chromenone derivatives were synthesized through an efficient three-step reaction starting from 4-hydroxybenzaldehyde. All the newly synthesized compounds were characterized by infrared and NMR spectroscopy as well as elemental analysis and evaluated for their acetylcholinesterase inhibitory activity.     

Novel generation of 9H-furo[3,2-b]chromen-9-ones from （E）-3-hydroxy-2-styrylchromones by excited state intramolecular proton transfer

Photocyclisation of substituted （E）-3-hydroxy-2-（V-methyl-2＇-phenylvinyl）-4-oxo-4H-1-benzopyrans to yield linear novel tricyclic 9H-furo[3,2-b]chromen-9-ones and angular fused tetracyclic xanthenones is described.     

MODIFIED COUMARINS. 3. PSORALEN AND ALLOPSORALEN ANALOGS

1,2,3,4-Tetrahydro-5H-benzo[c]furo[3,2-g]chromen-5-ones and 8,9,10,11-tetrahydro-7H-benzo[c]furo[2,3-f]chromen-7-ones, analogs of psoralen and allopsoralen, were synthesized from 1-hydroxy- and 3-hydroxy-7,8,9,10-tetrahydro-6H-benzo[c]chromen-6-ones.     

Synthesis and biological study of novel 5-{(4-(6,7-dihydrothieno-[3,2-c]pyridin-5(4H)-ylsulfonyl)phenylamino)-methyl}quinolin-8-ol and its metal complexes

A novel 5-((4-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-ylsulfonyl)phenylamino)methyl)quinolin-8-ol(HTPSMQol) was synthesized by optimized reaction of 4-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-ylsulfonyl)aniline with 5-chloromethyl-8-hydroxy-quinoline hydrochloride(CMHQ).Also complexes of HTPSMQol were prepared by using various M(Ⅱ) metal salts.All compounds were analyzed by spectroscopic techniques and screened against various strains of microorganisms.The results showed higher antimicrobial activity of HTPSMQol compared to its metal complexes and comparable with Ciprofloxacin.     

Modified Coumarins. 11. Synthesis and Biological Activity of Mannich Bases of Substituted 1,3-Dihydrocyclopenta[c]chromen-4-ones

Mannich bases containing the dialkylaminomethyl group in the 6- and 8-positions of 2,3-di-hydrocyclopenta[c]chromen-4-ones were prepared by condensation of 7- and 9-hydroxy-2,3-dihydrocyclopenta[c]chromen-4-ones with substituted 1,1-diaminomethanes. The effects of 8-chloro-7-hydroxy-6-(1-pyrrolidinylmethyl)-2,3-dihydrocyclopenta[c]chromen-4-one and 8-chloro-7-hydroxy-6-(morpholinomethyl)-2,3-dihydrocyclopenta[c]chromen-4-one on the central and peripheral nervous systemwere defined and enable the presence of tranquilizing and neuroleptic properties to be predicted.     

Synthesis,Characterization and In Vitro Evaluation of Novel 5-Ene-thiazolo[3,2-b][1,2,4]triazole-6(5H)-ones as Possible Anticancer Agents

The present paper is devoted to the search for drug-like molecules with anticancer properties using the thiazolo[3,2-b][1,2,4]triazole-6-one scaffold. A series of 24 novel thiazolo-[3,2-b][1,2,4]triazole-6-ones with 5-aryl(heteryl)idene- and 5-aminomethylidene-moieties has been synthesized employing three-component and three-stage synthetic protocols. A mixture of Z/E-isomers was obtained in solution for the synthesized 5-aminomethylidene-thiazolo[3,2-b]-[1,2,4]triazole-6-ones. The compounds have been studied for their antitumor activity in the NCI 60 lines screen. Some compounds present excellent anticancer properties at 10 μM. Derivatives 2h and 2i were the most active against cancer cell lines without causing toxicity to normal somatic (HEK293) cells. A preliminary SAR study had been performed for the synthesized compounds.     

Preparation of benzo[4,5]thiazolo[3,2-a]chromeno[4,3-d]pyrimidin-6-one derivatives using MgO-MgAl2O4 composite nano-powder

MgO-MgAl₂O₄ nanocomposite was prepared from the co-precipitation of Mg(NO₃)₂ and Al(NO₃)₃ salts, characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and fourier transform infrared spectroscopy (FTIR) techniques and evaluated in the synthesis of thirty five derivatives of benzo[4,5]thiazolo[3,2-a]chromeno[4,3-d]pyrimidin-6-ones (d₁-d₃₄) via the multi-component reaction of 4-hydroxycoumarins, aldehydes, and 2-aminobenzothiazole derivatives under solvent free condition. The catalytic activity of MgO-MgAl₂O₄ nanocomposite and the synthesis of the above mentioned compounds were investigated under thermal solvent free (times: 1.4–3 h; yields: 75–95%), ultrasonic irradiation (US) conditions (times: 1–2.5 h; yields: 69–97%) and using high-speed ball milling (HSBM) technique (times: 0.7–2.5 h; yields: 67–97%). In all cases, the products were obtained in excellent yields. Nuclear Magnetic Resonance (NMR) and MASS spectroscopy were used to characterize the structure of the desired product. The mechanism for the preparation of compounds d₁-d₃₄ was proposed and confirmed by ¹H NMR investigations.