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.     

Preparation of Calix[4]arene Alkylamine Derivatives by Mannich Reaction and use as Phase-Transfer Catalysts for Esterification Reaction

In this study, 5,11,17,23-tetrakis[(N-ethylpiperazine)methyl]-25,26,27,28-tetrahydroxycalix[4]arene (3) and 5,11,17,23-tetrakis[(4-carboethoxy-N-piperidino) methyl]-25,26,27,28-tetrahydroxycalix[4]arene (4) were synthesized in one step according to the Mannich reaction by the treatment of calix[4]arene with a secondary amine (N-ethylpiperazine, ethyl-4-piperidincarboxylate) and formaldehyde. The calix[4]arene derivatives (3, 4) were characterized by a combination of FTIR, ¹H NMR and elemental analyses. The synthesized compounds were used in an esterification reaction as the phase transfer catalyst. The catalytic efficiency of the calix[4]arenes 3 and 4 was evaluated by carrying out the ester-forming reaction of alkali metal carboxylates (sodium butyrate or sodium caprylate) with p-nitrobenzyl bromide. It was observed that the ester-forming reaction of alkali metal carboxylates with p-nitrobenzyl bromide, using calix[4]arene-based catalyst 3 as a phase-transfer catalyst in dichloromethan, provided the best yields.     

Microwave-assisted three component synthesis of novel bis-fused quinazolin-8(4H)-ones linked to aliphatic or aromatic spacer via amide linkages

Abstract

A novel series of bis(tetrahydro[1,2,4]triazolo[5,1-b]quinazolin-8-ones) and bis(tetrahydrobenzo[4,5]imidazo[2,1-b]quinazolinones) containing amide linkages were regionselectively prepared via a three-component reaction of bis(aldehydes) with dimedone and 3-amino-1,2,4-triazole (or 2-aminobenzimidazole) under conventional heating as well as under microwave irradiation.     

Synthesis and Reactions of 4-Oxiranylmethylfuro[3,2-b]pyrroles and Their Benzo Derivatives

Methyl 4-oxiranylmethyl-4H-furo[3,2-b]pyrrole-5-carboxylates 2a-c and methyl 1-oxiranylmethyl-1H-benzo[4,5]furo[3,2-b]pyrrole-2-carboxylate (2d) were prepared by reaction of the appropriate starting compounds 1a-d with excess chloromethyloxirane. The compounds 2a-d undergo oxirane ring opening by heterocyclic amines (morpholine, pyrrolidine, piperidine or 4-methylpiperazine) giving N-2-hydroxy-3-heteroaminopropyl-substituted compounds 3a-f or substituted 4,5-dihydrofuro[2',3':4,5]pyrrolo[2,1-c][1,4]oxazin-8-ones 4a-e.     

Synthesen und Eigenschaften ethinylierter und trimethylsilylethinylierter Molekülsysteme mit 1,6-Methano[10]annulen-Partialstruktur

2-Trimethylsilylethinylated 1,6-methano[10]annulene1 a was obtained by reaction of 2-bromo-1,6-methano[10]annulene with trimethylsilylacetylene in the presence of bis-(triphenylphosphin-)-Pd (II) chloride and Cu(I) and also by reaction of 1,1-diiodo-2-(1,6-methano[10]annulene-2-yl)-ethene (2) withn-buthyl-lithium followed by hydrolysis.1 a reacts with 2N NaOH to 2-ethinyl-1,6-methano[10]annulene (1 b). 2,7- and 2,10-dibromo-1,6-methano[10]annulene can be substituted to give the trimethylsilylethinylated compounds3 a–6 a, which then can be transformed with 2N NaOH into the desilylated products3 b–5 b.

Wolfgang Kraus, Stuttgart-Hohenheim, mit den besten Wünschen in Freundschaft zum 60. Geburtstag gewidmet     

Zur Synthese von 4-Aryl-5,6-dihydro-benzo[h]chinolinen

A new route to the benzo[h]quinoline system3 byMichael-addition of malononitrile to 2-arylidene-1-tetralones1 is presented. The mechanism of this reaction is elucidated by isolation of the intermediate 4H-naphtho[1,2—b]-pyrane2 and its reaction to3. The reaction is proposed to be a sequence of addition, cyclisation,Dimroth-rearrangement and disproportionation.

1. Mitt.:H.-H. Otto, Arch. Pharm. [Weinheim]307, 444 (1974).     

Synthesis and Dehydration of Oxadithia and Trithiadioxime Crown Compounds

The reaction of 2,2‐oxydiethanethiol and 2‐[2‐mercaptoethyl) thio] ethanethiol with dichloroglyoxime (DCGO) in absolute EtOH led to crown compounds, oxadithia (5Z,6Z)‐1,4,7‐oxadithiadiononane‐5,6‐dionedioxime (1) and trithia (2Z,3Z)‐1,4,7‐trithionane‐2,3‐dionedioxime (2), respectively. The compounds 5,6,8,9‐tetrahydro [1,4,7]oxadithionine[5,6‐c][1,2,5]oxadiazole (3) and 5,6,8,9‐tetrahydro[1,4,7]trithionino[2,3‐c][1,2,5]oxadiazole (4) were prepared by dehydration of 1 and 2 in aqueous solution of potassium hydroxide at 170–180°C, respectively.     

Synthesis of Some New 3-Alkylthio Derivatives of 1-Phenyl-1H-[1, 3, 4]thiadiazino[5, 6-b]quinoxalines

The synthesis of some new 3-(alkylthio)-1-phenyl-1H-[1, 3, 4]thiadiazino[5, 6-b]quinoxalines 4 have been achieved by cyclocondensation reaction of the alkyl-2-phenylhydrazinecarbodithioates 1 with 2,3-dichloroquinoxaline 2 in basic N,N-dimethylformamide.     

Functionalization of benzo[b][1,6]naphthyridine derivatives

Two routes to consecutive functionalization of 3-chloro-4-cyanobenzo[b][1,6]naphthyridine (1a) at positions 3 and 10 were developed. Oxidation of compound 1a with m-chloroperbenzoic acid in acetone leads to 3-chloro-4-cyano-10-oxobenzo[b][1,6]naphthyridine, while in acetic acid, the reaction gives 3-chloro-4-cyano-10-(3-chlorobenzoyloxy)-5-hydroxy-5,10-dihydrobenzo[b][1,6]naphthyridine. The reactions of 1a with some C-nucleophiles give -adducts at position 10. The reactions of N,N-dimethylamide acetals with chloride 1a leads to 4-cyano-3-dimethylaminobenzo[b][1,6]naphthyridine.     

Acetylenchemie, 33. Mitt.: Synthese von 2-substituierten Dihydrofuro[2,3-b]chinolinen

Summary The reaction of 3-iodo-4-methoxy-2(1H)-quinolinone (1) and 3-iodo-4,6,8-trimethoxy-2(1H)-quinolinone (2) with 2-methyl-3-butyn-2-ol under modified Heck-conditions gave the 2-substituted derivatives 2-(1-hydroxy-1-methylethyl)-4-methoxyfuro[2,3-b]-quinoline (3) and 2-(1-hydroxy-1-methylethyl-4,6,8-trimethoxyfuro[2,3-b]-quinoline (4). By a subsequent hydrogenation-reaction with a homogeneous catalyst (PtO₂/Rh₂O₃), the furoquinoline-derivatives yielded the dihydrofuro-[2,3-b]quinolines, identified as 2-(1-hydroxy-1-methylethyl-4-methoxy-2,3-dihydrofuro[2,3-b]quinoline (5) (racemic platydesmine) and 2-(1-hydroxy-1-methylethyl)-4,6,8-trimethoxy-2,3-dihydrofuro-[2,3-b]quinoline (6) (racemic precursor of O⁴-methylptelefolonium salt).

     

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.     

Acetylene chemistry,part 32: Alkinylation and cyclic rearrangement of theophylline with unsaturated alcohols by Mitsunobu reaction

Summary The reaction of theophylline (1) with 2-methyl-3-butyn-2-ol and 1-butyn-3-ol under Mitsunobu conditions gave the respective 9-substituted derivatives 9-[2-(2-methyl-3-butynyl)]-theophylline (2) and 9-[2-(3-butynyl)]-theophylline (3). On reaction with 2-methyl-3-buten-2-ol, theophylline yielded in addition to the 9-[2-(2-methyl-3-butenyl)]-theophylline (4), two more cyclic products, identified as 1,5,5a,8-tetrahydro-1,3,8,8-tetramethyl-2H-pyrrolo[1,2-e]purine-2,4(3H)-dione (5) and 8a,9-dihydro-1,3,6,6-tetramethyl-1H-pyrrolo[2,1-f]purine-2,4(3H,6H)-dione (7).

---

Acetylenchemie, 32. Mitt.: Alkinylierung und cyclische Umlagerung von Theophyllin mit ungesättigten Alkoholen mittels Mitsunobu-Reaktion

Zusammenfassung Die Reaktion von Theophyllin (1) mit 2-Methyl-3-butin-2-ol und 1-Butin-2-ol unter Mitsunobu-Bedingungen führte zu den 9-substituierten Derivaten 9-[2-(2-Methyl-3-butinyl)]-theophyllin (2) bzw. 9-[2-(3-Butinyl)]-theophyllin (3). Bei der Reaktion mit 2-Methyl-3-buten-2-ol ergab Theophyllin außer 9-[2-(2-Methyl-3-butenyl)]-theophyllin (4) noch zwei weitere cyclisierte Produkte, die als 1,3,8,8-Tetramethyl-1,5,5a,8-tetrahydro-pyrrolo[1,2-e]purin-2,4(3H)-dion (5) und 1,3,6,6-Tetramethyl-8a,9-dihydro-1H,6H-pyrrolo[2,1-f]purin-2,4-dion (7) identifiziert wurden.

     

A NOVEL ONE-POT SYNTHESIS OF 3-ARYLAZO-[1,2,4]TRIAZOLO-[4,3-a]PYRIMIDIN-5(1H)-ONES

A novel synthesis of 3-arylazo-1,7-disubstituted [1,2,4]triazolo[4,3-a]pyrimidinone-5(1H)-ones 8 via reaction of 2-thiouracil derivatives 3 and 4 with either 3-chloro- or 3-nitro-1,5-diarylformazans is reported.     

Pyridazine Derivatives and Related Compounds Part 19: 1 The Synthesis of Different Heterocycles from Ethyl 5-Amino-3,4-diphenylthieno[2, 3-c]pyridazine-6-carboxylate

7-substituted pyrido[2′, 3′: 4, 5]thieno[2, 3-c]pyridazines and 6-substituted pyrimido- [4′, 5′: 4, 5]thieno[2′, 3′: 4, 5]pyridazines were synthesized starting from ethyl 5-aminothieno[2′, 3′: 4, 5]pyridazino-6-carboxylate 1. The reaction of amino ester 1 with benzoyl isothiocyanate affords thiourea derivative 8, which undergoes further transformation to the related fused heterocyclic systems.     

Heterocyclic Synthesis via Enaminonitriles: an Efficient,One Step Synthesis of Some Novel Azolo[1,5-α]Pyrimidine,Pyrimido[1,2-α]-Benzimidazole,Pyrido[1,2-α]Benzimidazole Pyrimidine and Pyrazole Derivatives

Some novel pyrazolo[1,5-α]pyrimidines 5a-f, 10a,b, 1,2,4-triazolo[1.5-α]-pyrimidine (12), and pyrimido[1,2-α]benzimidazole 18 could be synthesized by reacting 3-(4-chlorophenyl)-2-(N,N-dimethylamino)methylene-3-oxopropanenitrile (2) with 5-amino-3- and/or 4-substituted-1H-pyrazoles 3a-f and 9a,b, 3-amino-1,2,4-triazole (11) and 2-aminobenzimidazole (14), respectively. The reaction of 2 with 1H-benzimidazol-2-ylacetonitrile (19) afforded the pyrido[1,2-α]benzimidazole 20. On the other hand, the reaction of 2 with guanidine, hydrazine, and phenyl hydrazine afforded the pyrimidine 24, and the pyrazoles 27, 28, respectively. However, the reaction of 2 with hydroxyl amine did not afford the isoxazole 32.     

[1]Benzofuro[3,2-<Emphasis Type="Italic">c</Emphasis>]pyridine synthesis and coordination reactions

(E)-3-(1-Benzofuran-2-yl)propenoic acid (1) was prepared from 1-benzofuran-2-carbaldehyde under the Doebner’s conditions. The obtained acid was converted to the corresponding azide 2, which was cyclized by heating in diphenyl ether to [1]benzofuro[3,2-c]pyridine-1(2H)-one (3). This compound was aromatized with phosphorus oxychloride to chloroderivative 4 which was reduced with zinc and acetic acid to the title compound 5. [1]Benzofuro[3,2-c]pyridine-2-oxide (6) was synthesized by reaction of 5 with 3-chloroperoxybenzoic acid in dichloromethane. Treatment of 6 with benzoyl chloride and potassium cyanide (Reissert-Henze reaction) was shown to produce the corresponding [1]benzofuro[3,2-c]pyridine-1-carbonitrile (7). The title compound was used for preparation of complexes Cu₂(ac)₄(bfp)₂ (8) and CoCl₂(bfp)₂ (9), where ac=CH₃CO₂⁻ and bfp=[1]benzofuro[3,2-c]pyridine. Both oxygen atom of carboxylate ions is used in the coordination to Cu(II). Thermal properties of the complexes 8 and 9 have been studied by TG and DTA and both complexes exhibited high thermal stability while complex 9 are thermally more stable than complex 8.     

Spiro[1,3-benzoxathiepin-4(5H),1′-cyclohexa[2,4]dien]-2,2′-dione,a Novel Heterocyclic Ring System

Abstract

Besides the common cyclisation reactions between divalent electrophiles such as Soc1₂, SC1₂, etc. and 2,2′-alkylidene-bisphenols 1 with selective attack by the two oxygens yielding dibenzo[d,g][1,3,2]dioxathiocines [1] we observed previously an unusual cyclisation of 1 with S₂CI₂ with a nucleophilic attack by the ortho- and para-carbon atoms (C(2) and C(4)) of bisphenol 1 [2]. We now report a new type of cyclocondensation reaction of 4,4′,6,6′-tetrasubstituted 2,2′-alkylidene-bisphenols 1 with ClSCOCl affording spiro[1,3-benzoxathiepin-4(5H),1′-cyclohexa[2,4]dien]-2,2′-diones 2 together with the cyclic carbonates 3. The structures of the products were elucidated mainly by ^l3C-NMR- and ¹H-NMR-spectroscopy. The mode of formation of the novel spiro thiocarbonates 2 resp. the known carbonates 3 [3] is discussed.     

Intramolecular Radical,Knoevenagel, or SN2′ Cyclization of Carbohydrate Derivatives for Access to Enantiomerically Pure 2-Oxospiroalkanes

Abstract

Intramolecular radical cyclization of D-glucose-derived substrate, (2R,3R,4R,5S)-2, 3-(isopropylidenedioxy)-5-[(1R)-l, 2-(isopropylidenedioxy)ethyl]-4-[3-bromo-3, 3-bis(methoxycarbonyl)propyl]-4-vinyltetrahydrofuran, 7 proceeded in a 6-endo-trig mode to give a derivative of 2-oxaspiro[4.5]decane 8 exclusively. Intramolecular Knoevenagel-like reaction of substrate 9 afforded derivatives of 2-oxaspiro-[4.4]nonane 10 as a 3:1 diastereomeric mixture. Intramolecular SN²′ displacement of substrate 22 proceeded highly stereoselectively giving a derivative of 2-oxaspiro-[4.4]decane 23.     

Synthesis and selected transformations of 1-(5-methyl-1-aryl-1H-1,2,3-triazol-4-yl)ethanones and 1-[4-(4-R-5-methyl-1H-1,2,3-triazol-1-yl)phenyl]ethanones

By cycloaddition of arylazides to acetylacetone are obtained derivatives of 1,2,3-triazole. In the reaction of 1-[5-methyl-1-(R-phenyl)-1H-1,2,3-triazol-4-yl] ethanones (IIa–IIe) and 1-[4-(4-R-5-methyl-1H-1,2,3-triazol-1-yl)phenyl] ethanones (VIIa-VIIe) with isatin are obtained 2-[1-(R-phenyl)-5-methyl-1H-1,2,3-triazol-4-yl]-4-quinolinecarboxylic acids (IIIa–IIIe) and 2-[4-(4-R-5-methyl-1H-1,2,3-triazol-1-yl)phenyl] -4-quinolinecarboxylic acids (IXa, IXb), respectively. We found that 1-[5-methyl-1-(R-phenyl)-1H-1,2,3-triazol-4-yl] ethanones (IIa–IIe) readily transform into [5-methyl-1-(R-phenyl)-1H-1,2,3-triazol-4-yl] acetic acids (IVa–IVc) by the method of Wilgerodt-Kindler. The (5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)acetic acid reacts with 5-phenyl-4-amino-4H-1,2,4-triazol-3-thiol affording 6-[(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl) methyl]-3-phenyl[1,2,4] triazolo[3,4-b] [1,3,4] thiadiazole (VI). Original Russian Text ? N.T. Pokhodylo, R.D. Savka, V.S. Matiichuk, N.D. Obushak, 2009, published in Zhurnal Obshchei Khimii, 2009, vol. 79, no. 2, pp. 320–325.     

A synthesis and biological screening of newly substituted 9-methyl-6-aryl-[1,2,4]triazolo[4,3-a][1,8]naphthyridines using chloranil

An effective, mild, and convenient method for the synthesis of 10 new substituted 9-methyl-6-aryl-[1,2,4]triazolo[4,3-a][1,8]naphthyridines (5a–j) by the oxidation of the corresponding 2-(2-ethylidenehydrazinyl)-3-aryl-1,8-naphthyridines (4a–j) using chloranil under conventional method has been described. The structures of synthesized compounds (5a–j) were established on the basis of their elemental analysis and spectral (IR, Mass, ¹³C- and¹H-NMR) data. The new compounds were synthesized with the objective of studying their antibacterial activity. The reaction will be characterized by easy workup, good efficacy, simple purification of the products, and availability of catalyst.