Mesoionic dimethyl derivatives of some 1,2,4-triazinones. The course of the reaction of 3,5-dimethoxy, 3-methoxy-5-methylthio, 5-methoxy-3- methylthio and 3,5-bis(methylthio)-1,2,4-triazine with methyl iodide

Treatment of 3,5-dimethoxy-1,2,4-triazine ( 1a ) with methyl iodide was found to give depending on the reaction time triazinium iodide 2a , triaziniumolates 4a and 6a as well as methoxytriazinones 7a and 8a . Thermolysis of 2a gave triaziniumolates 4a and 6a . Reaction of 2a , 4a or methoxytriazinone 9a with methyl iodide in acetonitrile yielded as the sole product 6a . Reaction of 3-methoxy-5-methylthio-1,2,4-tri-azine (1b ) with methyl iodide gave triazinium iodide 2b and methylthio triazinone 7b . Hydrolysis of 2a,b afforded 4a . Reaction of 5-methoxy-3-methylthio-1,2,4-triazine ( 1c ) with methyl iodide gave triazinium iodide 2c , triaziniumolate 4b , triazinium iodide 5b and triazinone 8b . Hydrolysis of 2c yielded 4b and its thermolysis gave a mixture of 4b and 5b . Reaction of 2c , 4b and triazinone 9b with methyl iodide afforded 5b . Treatment of 3,5-bis(methylthio)-1,2,4-triazine ( 1d ) with methyl iodide was found to give a mixture of N1 and N2 methiodides 2d and 3d which gave on hydrolysis 4b and 8b , respectively. Methylation of 6-methyl derivatives 1c-g gave analogous results, however the proportions of N1 methylated products were lower and the reaction rates higher in comparison to their respective lower homologues 1a,c,d . The structures of the mesoionic dimethyl derivatives were assigned from uv, ir, ¹H nmr and electron impact mass spectra. The structural assignments were eventually confirmed by quantum chemical calculations of net charge distributions, bond lengths and ipso angles of the C5?O bonds.     

(-)-(R)- and (+)-(S)-Carvone in the Synthesis of Optically Active Acetylenic Alcohols,Ethers, and Dichlorosilyl Derivatives

Reaction of butyllithium with acetylene and 1-hexyne gave the corresponding lithium acetylides which reacted with (-)-(R)- and (+)-(S-carvone in a stereospecific fashion to give lithium (1-ethynyl- or 1-hexynyl)-5-isopropenyl-2-methyl-2-cyclohexenolates. Hydrolysis of the latter gave individual optically active tertiary terpene alcohols having both acetylenic and p-menthene fragment. Their treatment with methyl iodide in the presence of hexamethylphosphoric triamide afforded the corresponding methyl ethers. The reaction of 3-ethynyl-5-isopropenyl-3-methoxy-2-methylcyclohexene with butyllithium and trichloro(vinyl)silane yielded optically active dichlorosilyl-containing acetylenic compounds.     

2-[3-(Trifluoromethyl)phenyl]furo[3,2-b]pyrroles: synthesis and reactions

The synthesis and reactions of methyl 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole-5-carboxylate (1a) are described. Upon reaction with methyl iodide, benzyl chloride, or acetic anhydride, this compound gave N-substituted products 1b-d. By hydrolysis of compounds 1a-c, the corresponding acids 2a-c were formed, or by reaction with hydrazine-hydrate, the corresponding carbohydrazides 3a-c were formed. By heating 2-[3-(trifluoromethyl)phenly]-4H-furo[3,2-b]pyrrole-5-carboxylic acid (2a) in acetic anhydride, 4-acetyl-2-[3-(trifluoromethyl)phenyl]furo[3,2-b]pyrrole (4) was formed. By hydrolysis of 4, 2-[3-(trifluoromethyl)phenyl]-4H-furo[3,2-b]pyrrole (5a) was formed, and reactions with methyl iodide or benzyl chloride gave N-substituted products 5b-c. The reaction of 4 with dimethyl butynedioate gave substituted benzo[b]furan 6. Compound 3a reacted with triethyl orthoesters giving 7a-c, which afforded with phosphorus (V) sulphide the corresponding thiones 8a-c. The thiones 8a-c reacted with hydrazine hydrate to form hydrazine derivatives 9a-c. The reaction of triethyl orthoformiate with compounds 9a-c led to furo[2′,3′: 4,5]pyrrolo[1,2-d][1,2,4]triazolo[3,4-f][1,2,4]triazines 10a-c. Hydrazones 11a-c were formed from 3a-c and 5-[3-(trifluoromethyl)phenyl]furan-2-carboxaldehyde. The effect of microwave irradiation on some condensation reactions was compared with “classical” conditions. The results showed that microwave irradiation shortens the reaction time while affording comparable yields.     

Synthesis and spectral properties of 2-methylthio-3H-4-(para-substituted-phenyl)-7-[(o-, and p-substituted)-phenylthio]-1,5-benzodiazepines

A series of twelve new 2-methylthio-3H-4-(p-substituted phenyl)-7-[(o-, and p-substituted)phenylthio]-1,5-benzodiazepines, which have potentially useful pharmacological properties, has been synthesized by condensing the 3,3-dimercapto-1-(para-substituted-phenyl)-2-propen-1-one with 3,4-diamino phenyl-R-phenylthio ethers, and subsequently the 1H-1,5-benzodiazepine-2-thiones obtained were treated with sodium hydride and methyl iodide. The structure of all products was corroborated by ir, ¹H-nmr, ¹³C-nmr and ms.     

Synthesis of α-(aminomethylene)-9H-purine-6-acetic acid derivatives

α-(Aminornethylene)-9H-purine-6-acetamide ( 3a ) and the corresponding ethyl acetate 9 have been synthesized by catalytic hydrogenation of 6-cyanomethylenepurine derivatives 2 and 7 which were obtained by the substitution of 6-chloropurine derivatives with α-cyanoacetamide and ethyl cyanoacetate, respectively. Substitution of α-(aminomethylene)-9-(tetrahydrofuran)-9H-purine-6-acetamide ( 3b ) with amines gave the corresponding N-alkyl- and N-arylamines 5 , which were treated with acid to give N-substituted α-(aminomethylene)-9H-purine-6-acetamides 6 . Substitution of 9 with amines gave the corresponding N-alkyl- and N-aryl substituted amines 10 .     

Methylation and amination of folic acid

The methylation of folic acid (2) with excess methyl iodide resulted in the formation of dimethyl 1,3-dimethylfolate ( 4 ), whereas, methylation of dimethyl folate ( 3 ) with an equimolar amount of methyl iodide gave mainly dimethyl 3-methylfolate ( 6 ). Both 4 and 6 underwent the Dimroth rearrangement in base to give the corresponding 2-deamino-2-methyiamino folic acids 5 and 7, respectively. Amination of 2 with hydroxylamine-O-sulfonic acid in dilute base gave a low yield of 3-amino folic acid (8), which underwent Dimroth rearrangement to give 2-deamino-2-hydrazino folic acid (9) in an acidic, but not a basic, medium.     

Synthesis of 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide

The reaction of methyl 2-bromo-6-(trifluoromethyl)-3-pyridinecarboxylate ( 1 ) with methanesulfonamide gave methyl 2-[(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridine-carboxylate ( 2 ). Alkylation of compound 2 with methyl iodide followed by cyclization of the resulting methyl 2-[methyl(methylsulfonyl)amino]-6-(trifluoromethyl)-3-pyridinecarboxylate ( 3 ) yielded 1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 4 ). The reaction of compound 4 with α,2,4-trichlorotoluene, methyl bromopropionate, methyl iodide, 3-trifluoromethylphenyl isocyanate, phenyl isocyanate and 2,4-dichloro-5-(2-propynyloxy)phenyl isothiocyanate gave, respectively, 4-[(2,4-dichlorophenyl)methoxy]-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazine 2,2-dioxide ( 5 ), methyl 2-[[1-methyl-2,2-dioxido-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4-yl]oxy]propanoate ( 6 ), 1,3,3-trimethyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2]thiazin-4(3H)-one 2,2-dioxide ( 7 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-[3-(trifluoromethyl)phenyl]-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 8 ), 4-hydroxy-1-methyl-7-(trifluoromethyl)-N-phenyl-1H-pyrido[2,3-c][1,2]thiazine-3-carboxamide 2,2-dioxide ( 9 ) and N-[2,4-dichloro-5-(2-propynyloxy)phenyl]-4-hydroxy-1-methyl-7-(trifluoromethyl)-1H-pyrido[2,3-c][1,2] thiazine-3-carboxamide 2,2-dioxide ( 10 ).     

Pyridazine Derivatives and Related Compounds,Part 1. Some Reactions with 4-Cyano-5,6-Diphenyl-2,3-Dihydropyridazine-3-One

4-Cyano-5,6-diphenyl-2,3-dihydropyridazine-3-onc 1 reacts with phosphorous oxychloride to give 70% of the corresponding 3-chloro derivative 2. Treating 2 with anthranilic acid in butanol, 4-cyano-2,3-diphenyl-10H-pyridazino[6,1-b]quinoxaline-10-one, 3 was obtained. Compound 1 reacts with phosphorous pentasulphide to give 3-mercapto derivative 4, which was converted by acrylonitrile to S-(2-cyanoethyl)pyridazine derivative 5. Compound 4 reacts with ethyl bromoacetate and with phenacyl bromide gave the corresponding thieno[2,3-c] pyridazine derivatives 8, 9, Alkylation of 1 with ethyl chloroacetate afforded 3-0-carbethoxymethyl derivative 10. Compound 10 reacts with amines (aniline, hydrazine) to give the corresponding amide and acid hydrazide 13, 12 respectively. Hydrolysis of 10 with sodium hydroxide gave the corresponding acid derivative 11. Treating 1 with methyl iodide, 3-0-methyl derivative 14 was obtained, which was converted by ammonium acetate/acetic acid to 3-amino-4-cyano-5,6-diphenyl pyridazine 15. Compound 1 reacts with methyl magnesium iodide gave 4-acetyl derivative 16, which was reacted with hydrazine, phenyl hydrazine and with hydroxylamine to give the substituted I H pyrazolo [3,4-c] pyridazine 17 a,b and isoxazolo [5,4-c] pyridazine 18 derivatives respectively.     

Synthesis of novel dihydrothiazolo[3,2-a]pyrimidinone derivatives

Condensation of 2-amino-4-hydroxy-2-mercaptopyrimidine (2) hydrate and ethyl 4-bromocrotonate gave a mixture of ethyl 7-amino-2,3-dihydro-5-oxo-5H-thiazolo[3,2-a]pyrimidine-3-acetate (4) and 2a,3-dihydro-1-thia-5,8,8b-triazaacenaphthylene-4,7(2H)-dione (5) whereas reaction of 2 with 4-bromocrotononitrile afforded only 7-amino-2,3-dihydro-5-oxo-5H-thiazolo[3,2-a] pyrimidine-3-acetonitrile. Reaction of the tricycle 5 (which was isolated as a hemihydrate) with excess methyl iodide/potassium carbonate in dimethylformamide resulted in both ring hydrolysis and methylation to give 3,4-dihydro-1,7-dimethyl-4- [(methylthio)methyl]-2H-pyrimido[1,6-a]pyrimidine-2,6,8(1H,7H)-trione (10). Methylating 5 with excess methyl iodide/sodium methoxide in methanol also resulted in ring fragmentation and methylation but instead afforded methyl 7-methyl-amino-2,3-dihydro-5-oxo-7H-thiazolo[3,2-a]pyrimidine-3-acetate. The mechanistic aspects of these reactions are discussed.     

Cycloaddition of primary phosphines to divinyl sulfide

Primary phosphines reacted with divinyl sulfide under radical initiation conditions (AIBN, 65–70°C, reactant molar ratio 1:1) according to the addition-cyclization pattern to give 4-substituted 1,4-thiaphosphinanes which underwent almost quantitative oxidation with oxygen or elemental sulfur, yielding the corresponding 4-substituted 1,4-thiaphosphinane oxides (sulfides). The reaction of 4-(2-phenylethyl)-1,4-thiaphosphinane with methyl iodide afforded 4-methyl-4-(2-phenylethyl)-1,4-thiaphosphinanium iodide with high chemoselectivity.     

A facile synthesis of 3-substituted 2-cyanoquinazolin-4(3H)-ones and 3-alkyl-2-cyanothieno[3,2-d]pyrimidin-4(3H)-ones via 1,2,3-dithiazoles

The reaction of methyl anthranilate with 4,5-dichloro-1,2,3-dithiazolium chloride (Appel's salt) in the presence of pyridine (2 equivalents) in dichloromethane at room temperature gave methyl N-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)anthranilate ( 3a ) (50% yield), which reacted with sterically less hindered primary alkylamines to give directly 3-alkyl-2-cyanoquinazolin-4(3H)-ones 5 in moderate to good yields. With tert-butylamine, N-(2-methoxycarbonylphenyl)iminocyanomethyl N-(tert-butyl) disulfide 7 and methyl 2-(N-cyanothioformamido)anthranilate ( 8 ) were isolated in 33% and 59% yields, respectively. The cyano group of quinazoline 5a (R = CH₃) is readily displaced by various nucleophiles to give 2-substituted quinazolinones 11–19 , which indicates that compounds 5 can be utilized as starting materials for the synthesis of new 2-substituted quinazolines. Similarly 3-alkyl-2-cyanomieno[3,2,-d]pyrimidin-4(3H)-ones 22 were prepared from methyl 3-[N-(4-chloro-5H-1,2,3-dimiazol-5-ylidene)]-2-thiophencarboxylate ( 21 ) in moderate to good yields.     

Synthesis and biological activities of 1-[2-(dimethylamino)ethyl]- and 1-[3-(dimethylamino)propyl]-substituted 3-methyl-1,8-dihydrocycloheptapyrazol-8-ones and related compounds.

3-Methyl-1,8-dihydrocycloheptapyrazol-8-ones (2a-c), prepared from 3-acetyltropolones (1a-c), were treated with diazomethane, methyl iodide, dimethyl sulfate, and diethyl sulfate to give 1- and 2-alkylated compounds. The 1,8-dihydrocycloheptapyrazol-8-one (2a) also reacted with 2-(dimethylamino)ethyl, 2-(diethylamino)ethyl, 3-(dimethylamino)propyl, and 2,3-dihydroxypropyl chloride to afford the corresponding 1-substituted products. A preliminary study was made of the biological activities of some of the obtained compounds.     

Synthesis of pyrazolo[3,4-c][1,2]thiazin-4(3H)-one 2,2-dioxides,new heterocycles

The reaction of substituted ethyl 5-aminopyrazole-4-carboxylates with two equivalents of methanesul-fonyl chloride gave the substituted ethyl 5-[bis(methylsufonyl)amino]-1H.-pyrazole-4-carboxylates II . Removal of one of the methanesulfonyl groups, followed by alkylation of the ethyl 5-[(methylsulfonyl)amino]-1H-pyrazole-4-carboxylates III with methyl iodide produced the substituted ethyl 5-[methyl(methylsulfonyl)amino]-1H-pyrazole-4-carboxylates IV . Treatment of IV with sodium hydride gave the 7-substituted 1,7-dihydro-1-methylpyrazolo[3,4-c][1,2]thiazin-4(3H)-one 2,2-dioxides V .     

Preparation of 6-(nitron-c-yl)- and 6-(1,3-butadienyl)-2-pyrones and their cycloaddition reactions

6-(N-Substituted nitron-C-yl)-2-pyrones 1 and 6-(4-substituted 1,3-butadienyl)-2-pyrone 2 were prepared and their cycloaddition reactions with three kinds of diene systems were investigated. Namely, the reactions of 1 with methyl acrylate, vinyl crotonate and divinylsulfone took place at the nitrone moiety to afford 3-substituted isoxazolidines 9–14 , and that of 2 with maleimide took place at the 2-pyrone moiety to give a bis-adduct 17 via elimination of carbon dioxide.     

Access to the 2,3-dihydropyridazin-3-one and as-triazino[3,4-a]phthalazine ring systems from 4-aryl-2-oxo-butanoic acids

A novel series of 2,3-dihydropyridazin-3-ones 15 were synthesized via condensation between hydrazines and 4-(p-chlorophenyl)-2-hydroxy-2-(2-oxo-2-substituted ethyl)butanoic acids 8 which in turn were prepared by the reaction of substituted benzylpyruvic acids 6 with methyl alkyl(aryl) ketones 7. Dehydration of 8b-d by a mixture of glacial acetic acid and hydrochloric acid afforded 4-(p-chorophenyl)-2-(substituted phenacyl)-2-butenoic acids 10. Condensation reaction of 10 with hydrazines gave type 15 compounds in good yields. Also, a new series of as-triazino[3,4-a]phthalazines 20 was obtained from the reaction of substituted benzylpyruvic acids 6 with hydralazine to give the hydralazones 19 which underwent dehydrative cyclization reaction with PPA to afford 20. Structure assignments are based on ¹H, ¹³C nmr and ir spectra.     

A new route to 7-substituted derivatives of n-[4-(2-[2-amino-3,4-dihydro-4-oxo-7H-pyrrolo(2,3-d)pyrimidin-5-yl]ethyl)benzoyl]-L-glutamic acid [ALIMTA (LY231514, MTA)

Alkylation of various primary amines with crotyl bromide, followed by DMAP-promoted acylation with methyl malonyl chloride to 4 and then manganic triacetate dihydrate/cupric acetate induced radical cyclization, gave 1-substituted-4-vinyl-3-carbomethoxy-2-pyrrolidinones (5). Thiation to the thiolactams 6 and guanidine cyclization then gave a series of 2-amino-3,4-dihydro-4-oxo-5-vinyl-7-substituted pyrrolo[2,3-d]pyrimidines (7). Palladium-catalyzed C-C coupling with diethyl 4-iodobenzoylglutamate led in one step via an unexpected redox reaction to the diethyl esters 9 of a series of 7-substituted derivatives of ALIMTA (LY231514, MTA), from which the target analogues 10 were readily prepared by saponification. Attempted deprotection at position 7 was successful in only one case (9d, R = CH(2)C(6)H(3)(OMe)(2)(-3',4'), which resulted in a known pentultimate precursor (9, R = H) of ALIMTA. The 7-substituted derivatives 10 proved to be inactive in vitro as inhibitors of cell division.     

Synthesis of 5-(4-substituted benzyl)-2,4-diaminoquinazolines as inhibitors of candida albicans dihydrofolate reductase

Several 5-(4-substituted benzyl)-2,4-diaminoquinazolines were prepared as potentially selective inhibitors of Candida albicans dihydrofolate reductase. These compounds were synthesized by a novel route, which included as a key step the displacement of a fluoro group in 2,6-difluorobenzonitrile by the anions of ethyl or methyl 4-substituted phenylacetates. The resultant diarylacetates were saponified and decarboxylated to the 2-fluoro-6-(4-substituted phenyl)benzonitriles. Ring closure of these benzonitriles with guanidine carbonate gave the 5-(4-substituted benzyl)-2,4-diaminoquinazolines.     

Synthesis of new visnagen and khellin furochromone pyrimidine derivatives and their anti-inflammatory and analgesic activity

6-[(4-Methoxy/4,9-dimethoxy)-7-methylfurochromen-5-ylideneamino]-2-thioxo-2,3-dihydropyrimidin-4-ones 1a,b were prepared by reaction of 6-amino-2-thiouracil with visnagen or khellin, respectively. Reaction of 1a,b with methyl iodide afforded furochromenylideneaminomethylsulfanylpyrimidin-4-ones 2a,b. Compounds 2a,b were reacted with secondary aliphatic amines to give the corresponding furochromen-ylideneamino-2-substituted pyrimidin-4-ones 3a-d. Reaction of 3a-d with phosphorus oxychloride yielded 6-chlorofurochromenylidenepyrimidinamines 4a-d, which were reacted with secondary amines to afford furochromenylideneamino-2,6-disubstituted pyrimidin-4-ones 5a-d. In addition, reaction of 5a-d with 3-chloropentane-2,4-dione gave 3-chloro-furochromenylpyrimidopyrimidines 6a-d. The latter were reacted with piperazine and morpholine to give 1-(furochromenyl)-pyrimidopyrimidine-3,6,8-triylpiperazines or -3,6,8-triylmorpholines 7a-d. The chemical structures of the newly synthesized compound ware characterized by IR, 1H-NMR, 13C-NMR and mass spectral analysis. These compounds were also screened for their analgesic and anti-inflammatory activities. Some of them, particularly 3-7, exhibited promising activities.     

Synthesis of α-(aminomethylene)-9-(methoxymethyl)-9H-purine-6-acetic acid derivatives

α-(Aminomethylene)-9-(methoxymethyl)-9H-purine-6-acetamide and the ethyl acetate, 3 and 8 , have been synthesized by catalytic hydrogenation of 6-cyanomethylene-9-methoxymethylpurine derivatives 2 and 7 which were obtained by the substitution of 6-chloro-9-(methoxymethyl)purine ( 1 ) with α-cyanoacetamide and ethyl cyanoacetate, respectively. Substitution of 3 and 8 with amines gave the corresponding N-substituted α-(aminomethylene)-9-(methoxymethyl)-9H-purine-6-acetamide and the ethyl acetate 4 and 10 . Reaction of 3 with piperidine gave 9-(methoxymethyl)-9H-purine-6-acetamide ( 5 ).     

Furopyridines. VI. Preparation and reactions of 2- and 3-substituted furo[2,3-b]pyridines

This paper describes the synthesis and chemical properties of some 2- and 3-substituted furo[2,3-b]pyridines. Reaction of ethyl 2-chloronicotinate 1 with sodium ethoxycarbonylmethoxide or 1-ethoxycarbonyl-1-ethoxide gave β-keto ester 2 or ketone 5 , respectively. Ketonic hydrolysis of 2 afforded ketone 3, from which furo[2,3-b]pyridine 4 was obtained by the method of Sliwa. While, 2-methyl derivative 7 was prepared from 5 by reduction, O-acetylation and the subsequent pyrolysis. Reaction of ketone 3 with methyllithium gave tertiary alcohol 8 which was O-acetylated and pyrolyzed to give 3-methyl derivative 9 . Formylation of 4 , via lithio intermediate, with DMF yielded 2-formyl derivative 10 , from which 7 , was obtained by Wolff-Kishner reduction. Dehydration of the oxime 11 of 10 gave 2-cyano derivative 12 , which was hydrolyzed to give 2-carboxylic acid 13 . Reaction of 3-bromo compound 14 with copper(I) cyanide gave 3-cyano derivative 15 . Alkaline hydrolysis of 15 afforded compound 16 and 17 , while acidic hydrolysis gave carboxamide 18 . Reduction of 15 with DIBAL-H afforded 3-formyl derivative 19 . Wolff-Kishner reduction of 19 gave no reduction product 9 but hydrazone 20 . Reduction of tosylhydrazone 21 with sodium borohydride in methanol afforded 3-methoxymethylfuro[2,3-b]pyridine 22 .