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.     

Modified Coumarins. 17. Synthesis and Anticoagulant Activity of 3,4-Cycloannelated Coumarin D-Glycopyranosides

3,4-Cyclocondensed coumarin O-glycopyranosides containing glucose, galactose, xylose, and arabinose were synthesized by condensation of potassium salts of hydroxycoumarins and acetobromosugars. 7-(β-D-Galactopyranosyloxy)-2,3-dihydrocyclopenta[c]chromen-4-one, 3-(β-D-xylopyranosyloxy)-7,8,9,10-tetrahydrobenzo[c]chromen-6-one, and 3-(α-D-arabinopyranosyloxy)benzo[c]chromen-6-one exhibited distinct anticoagulant activity. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 416–419, September–October, 2005.     

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.     

Modified Coumarins. 6. Synthesis of Substituted 5,6-Benzopsoralens

Substituted 5H-benzo[c]furo[3,2-g]chromen-5-ones, modified analogs of psoralen that contain a benzene ring annelated at the 5,6-position of a furo[3,2-g]chromen-7-one system, were synthesized from 3-hydroxy- 6H-benzo[c]chromen-6-ones.     

Regioselective synthesis of 4-chlorophenols, 10-chloro-7-hydroxy-6H-benzo[c]chromen-6-ones, and 4-chloro-1-hydroxy-9H-fluoren-9-ones based on [3+3] cyclizations of 1,3-bis(silyloxy)-1,3-dienes with 2-chloro-3-silyloxy-2-en-1-ones

A variety of 4-chlorophenols, 10-chloro-7-hydroxy-6H-benzo[c]chromen-6-ones, and 4-chloro-1-hydroxy-9H-fluoren-9-ones were prepared by formal [3+3] cyclizations of 1,3-bis(silyloxy)-1,3-dienes with 2-chloro-3-(silyloxy)alk-2-en-1-ones.     

Modified Coumarins. 4. Synthesis and Biological Properties of Cyclopentaneannelated Furocoumarins

Psoralen and allopsoralen analogs that contain an annelated cyclopentane were synthesized from 7-hydroxyand 9-hydroxy-1,2,3,4-tetrahydrocyclopenta[c]chromen-4-ones. 9-Phenyl-1,2,3,4-tetrahydrocyclopenta[c]furo[3,2-g]chromen-4-one exhibited low toxicity, acted as a CNS stimulant, and exhibited cardiotropic activity.     

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     

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 9-azolyl-3-(4-phenyl-4h-1,2,4-triazol-3-yl)-4h,8h-pyrano-[2,3-<Emphasis Type="Italic">f</Emphasis>]chromene-4,8-diones

The reaction of 6-ethyl-8-formyl-7-hydroxy-3-(4-phenyl-4H-1,2,4-triazol-3-yl)chromone with 2-azolyl-acetonitriles gave 8-iminopyrano[2,3-f]chromen-4-ones, whose acid hydrolysis led to pyrano-[2,3-f]chromene-4,8-diones containing azaheterocyclic substituents at C-3 and C-9.     

Studies on the esterifications of 9-（hydroxyimino）-4-methyl-8,9-dihydrofuro[2,3-h]chromen-2-one with acid chlorides under different conditions

The esterifications of 9-（hydroxyimino）-4-methyl-8,9-dihydrofuro[2,3-h]chromen-2-one （4） with acid chlorides afforded normal oxime-esters 3a-e in 35-78% yields in presence of excessive 4-dimethylaminopyridine as the acid scavenger, whereas the reactions gave unexpected 8-substituted products N-（8-chloro-4-methyl-2-oxo-2H-furo-[2,3-h]chromen-9-yl）amides （5a-c） and 4-methyl-2,9-dioxo-8,9-dihydro-2H-furo[2,3-h]chromen-8-ylcarboxyloates （6d-e） by using excessive acid chlorides. The structures of 10 new compounds were determined by 1H NMR, 13C NMR, MS and HRMS, and the possible mechanism for the formation of unexpected products 5a--c and 6d-e was also proposed.     

Modified coumarins. 13. Synthesis of cyclopentane-annelated pyranocoumarins

Modified pyranocoumarins containing a condensed cyclopentane fragment were synthesized by adjoining a 2,2-dimethyltetrahydropyran ring to a 2,3-dihydrocyclopenta[c]chromen-4-one system and annelation of a pyrone ring to a 2,2-dimethylchromane.Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 352–357, September–October, 2004.     

Reactions of 2-sulfanylethanol with mucochloric acid and its derivatives

Mucochloric acid reacted with 2-sulfanylethanol in the presence of triethylamine to give 3-chloro-5-hydroxy-4-(2-hydroxyethylsulfanyl)furan-2(5H)-one which underwent acid-catalyzed cyclization to 7-chloro-2,3,4a,6-tetrahydrofuro[2,3-b][1,4]oxathiin-6-one. Likewise, reactions of 5-alkoxy-3,4-dichlorofuran-2(5H)-ones with 2-sulfanylethanol in the presence of triethylamine involved replacement of chlorine in position 4 of the furan ring with formation of the corresponding 4-(2-hydroxyethylsulfanyl) derivatives. The reaction of mucochloric acid with 2-sulfanylethanol in excess aqueous potassium hydroxide resulted in the formation of an acyclic product, 3-(2-hydroxyethylsulfanyl)-2-chloroprop-2-enoic acid. The structure of 7-chloro-2,3,4a,6-tetrahydrofuro[2,3-b][1,4]oxathiin-6-one and 3-(2-hydroxyethylsulfanyl)-2-chloroprop-2-enoic acid was proved by X-ray analysis.     

Synthesis and cytotoxic activity of benzopyranoxanthone analogues of benz.

Condensation of 3-hydroxy-2-naphthalenecarboxylic acid with phloroglucinol afforded 1,3-dihydroxy-12H-benzo[b]xanthen-12-one. Construction of an additional dimethylpyran ring onto this skeleton, by alkylation with 3-chloro-3-methyl-1-butyne followed by Claisen rearrangement, gave access to a series of benzo[b]pyrano[2,3-i]xanthen-6-ones and benzo[b]pyrano[3,2-h]xanthen-7-ones related to psorospermine and benzo[b]acronycine. In contrast with what is observed in the pyridoacridone and benzopyridoacridone series, the linear benzo[b]-pyrano[2,3-i]xanthen-6-one derivatives were more potent than their angular benzo[b]pyrano[3,2-h]xanthen-7-one isomers. cis-3,4-Diacetoxy-5-methoxy-2,2-dimethyl-3,4-dihydro-2H,6H-benzo[b]pyrano[2,3-i]xanthen-6-one, the most active among the new compounds, was more potent than acronycine in inhibiting the proliferation of L1210 murine leukemia cells.     

Furyl analogs of α-pyrono[2,3-<Emphasis Type="Italic">f</Emphasis>]isoflavones with an azole substituent in the α-pyrone nucleus

The corresponding 9-azolyl-8-imino-4H,8H-pyrano[2,3-f]chromen-4-ones have been synthesized by the condensation of 7-hydroxy-3-(5-methoxycarbonyl-2-methylfuran-3-yl)-8-formylchromones with 2-aza-hetarylacetonitriles. Acid hydrolysis of the products led to the furyl analogs of 9-azolyl-α-pyrono-[2,3-f]isoflavones.     

Synthesis of Sulfur Heterocycles by Thio-<Emphasis Type="Italic">Claisen</Emphasis> Rearrangement

Summary. 7-Chloro-4-hydroxydithiocoumarin was alkylated with allylic halides under phase transfer catalysis condition in the presence of TBAB or BTEAC in chloroform-aqueous NaOH (1%) at room temperature. 2,3-Dichloroprop-2-ene on similar treatment with 7-chloro-4-hydroxydithiocoumarin afforded 2-methylthieno[2,3-b]thiochromen-4-one in 65% yield. The S-alkylated thiochromen-4-ones were then refluxed in quinoline to give 7-chloro-2,3-dihydrothieno[2,3-b]thiochromen-4-ones or 7-chloro-2,3,4-trihydrothiopyrano[2,3-b]thiochromen-5-ones or 7-chloro-2,3-dihydro-3-vinylthieno[2,3-b]thiochromen-4-one.     

Iodine catalyzed synthesis of the chromene derivatives in one-pot

Iodine catalyzed one-pot reactions of salicylaldehyde and dimolecular 1 H-indene-1,3(2H)-dione,barbituric acids,4-hydroxycoumarin, or 4-hydroxy-6-methylpyran-2-one were performed and provided a rapid,convenient and general approach to synthesize the chromene derivatives.2-(11-Oxo-10,11-dihydroindeno[l,2-b]chromen-10-yl)-1H-indene-1,3(2H)-diones P1-P4 and 10-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-3-methylpyrano[4,3-6]chromen-1(10H)-ones P8-P9 were unprecedentedly prepared and structurally identified by NMR and Mass.The confirmation of structure by single crystal X-ray crystallography is reported for P3.     

Reaction of Dimethyl Sulfoxide with 4-Acyloxycoumarins

Dimethyl sulfoxide converts 4-acetoxycoumarin (1) exclusively to 2-(2-hydroxybenzoyl)-2-[(methylthio)methyl]-2,3-dihydro-4 H-furo[3,2-c]chromen-4-one (3) at 180°C under a nitrogen atmosphere, but in the absence of nitrogen, the products obtained are dicoumarol and its dehydrative cyclization products 7 H-bis[1]benzopyrano[4,3-b: 3′,4′-c]pyran-6,8-dione (9) and (3). Under similar conditions, 4-benzoyloxycoumarin (1a) affords benzoic acid, 4-hydroxy-3-({2-[(methylthio)methyl]-3-oxo-2,3-dihydro-1-benzofuran-2-yl}methyl)-2H-chromen-2-one (7), and 3-(2-hydroxybenzoyl)-3,4-dihydro-2H,5H-pyrano[2,3-b] chromen-5-one (8).     

Synthesis of Sulfur Heterocycles by Thio- Claisen Rearrangement

7-Chloro-4-hydroxydithiocoumarin was alkylated with allylic halides under phase transfer catalysis condition in the presence of TBAB or BTEAC in chloroform-aqueous NaOH (1%) at room temperature. 2,3-Dichloroprop-2-ene on similar treatment with 7-chloro-4-hydroxydithiocoumarin afforded 2-methylthieno[2,3-b]thiochromen-4-one in 65% yield. The S-alkylated thiochromen-4-ones were then refluxed in quinoline to give 7-chloro-2,3-dihydrothieno[2,3-b]thiochromen-4-ones or 7-chloro-2,3,4-trihydrothiopyrano[2,3-b]thiochromen-5-ones or 7-chloro-2,3-dihydro-3-vinylthieno[2,3-b]thiochromen-4-one.     

Synthesis and antimicrobial activity of some derivatives of (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide

(7-Hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid hydrazide (2) was prepared from (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid ethyl ester (1) and 100% hydrazine hydrate. Compound 2, is the key intermediate for the synthesis of several series of new compounds such as Schiff's bases 3a-l, formic acid N'-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)acetyl] hydrazide (4), acetic acid N'-[2-(7-hydroxy-2-oxo-2H-chromen-4- yl)-acetyl] hydrazide (5), (7-hydroxy-2-oxo-2H-chromen-4-yl)-acetic acid N'-[2-(4- hydroxy-2-oxo-2H-chromen-3-yl)-2-oxoethyl] hydrazide (6), 4-phenyl-1-(7-hydroxy-2- oxo-2H-chromen- 4-acetyl) thiosemicarbazide (7), ethyl 3-{2-[2-(7-hydroxy-2-oxo-2H- chromen-4-yl)-acetyl]hydrazono}butanoate (8), (7-hydroxy-2-oxo-2H-chromen-4-yl)- acetic acid N'-[(4-trifluoromethylphenylimino)methyl] hydrazide (9) and (7-hydroxy-2- oxo-2H-chromen-4-yl)acetic acid N'-[(2,3,4-trifluorophenylimino)-methyl] hydrazide (10). Cyclo- condensation of compound 2 with pentane-2,4-dione gave 4-[2-(3,5- dimethyl-1H-pyrazol-1-yl)-2-oxoethyl]-7-hydroxy-2H-chromen-2-one (11), while with carbon disulfide it afforded 7-hydroxy-4-[(5-mercapto-1,3,4-oxadiazol-2-yl)methyl]-2H- chromen-2-one (12) and with potassium isothiocyanate it gave 7-hydroxy-4-[(5- mercapto-4H-1,2,4-triazol-3-yl)methyl]-2H-chromen-2-one (14). Compound 7 was cyclized to afford 2-(7-hydroxy-2-oxo-2H-chromen-4-yl)-N -(4-oxo-2-phenylimino- thiazolidin-3-yl) acetamide (15).     

A Facile One-Step Synthesis of New Types of 8-Thiazolyl and 8-Thiadiazinyl Coumarins

N-[4-(7-Methoxy-4-methyl-2-oxo-2H-chromen-8-yl)-thiazol-2-yl]-guanidine ( 2 ) has been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) with guanylthiourea. 4-Methyl-7-methoxy-8-[2-(N′-(1-phenyl-ethylideneisopropylidene)-hydrazino]-thiazol-4-yl]chromen-2-ones ( 3 , 4 , and 5 ) have been prepared by reaction of 4-methyl-7-methoxy-8-(2-bromoacetyl) coumarin ( 1 ) and thiosemicarbazide in presence of acetophenone or acetone without any solvent. The formation of these compounds was further confirmed by the condensation of acetophenone/acetone thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) in anhydrous ethanol in a two-step process. Similarly 8-[2-[N′-(benzylidene)hydrazine]-thiazol-4-yl]-7-methoxy-4-methyl-chromen-2-ones ( 6 , 7 , and 8 ) have been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)chromen-2-one with thiosemicarbazide and various aromatic aldehydes in a single step without any solvent. The formation of these compounds was further confirmed by the condensation of appropriately substituted benzaldehyde thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin in anhydrous ethanol. 4-Methyl-7-methoxy-8-(2-bromoacetyl) chromen-2-one (1) upon condensation with 3,5-dimercapto-4-amino-s-triazole in anhydrous ethanol resulted in the formation of 8-(3-mercapto-3H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl)-7-methoxy-4-methyl chromen-2-one (9). This compound ( 9 ) on reaction with various alkyl and phenacyl halides in anhydrous ethanol gave corresponding 4-methyl-7-methoxy-8-[3-(2-oxo-substituted sulphanyl)-7H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl]chromen-2-ones ( 10 to 18 ). The structures of newly prepared compounds have been confirmed from analytical and spectral data.