Apparent molar heat capacities and volumes of some alkylated derivatives of uracil and adenine in aqueous solution at 25°C

Densities and apparent molar heat capacities of some alkylated derivatives of uracil and adenine: 1-methyluracil, 1,3-dimethyluracil, 1,3-diethylthymine, 5,6-trimethylene-1,3-dimethyluracil, 5,6-tetramethylene-1,3-dimethyluracil, 5,6-pentamethylene-1,3-dimethyluracil, 2,9-dimethyladenine, 2-ethyl-9-methyladenine, 2-propyl-9-methyladenine, 8-ethyl-9-methyladenine, 6,8,9-trimethyladenine and 8-ethyl-6,9-dimethyladenine were determined using flow calorimetry and flow densimetry at 25°C. It was found that the partial molar volumes and heat capacities correlate linearly with the number of substituted methylene groups-CH ₂ -as well as to the number of hydrogen atoms, n _H , belonging to the skeleton of the molecule. In the case of alkylated uracils a difference was observed in the values at infinite dilution V ₂ ^o and C _p2 ^o , depending on the substitution of alkyl and cyclooligomethylene groups.     

Functionalization of the periphery of calix[4]resorcinarenes with P(III)-containing substituents via hydroxy,trimethylsiloxy, and ethoxy-tethered trimethylsiloxy intermediates

Unlike C-undecylcalix[4]resorcinarene, C-methylcalix[4]resorcinarene 1 reacted with chlorodifluorophosphine in the absence of an auxiliary base to give the unstable octakis(difluorophosphite)-substituted derivative 2. The existence of two conformational isomers of 2 in solution was observed by ¹⁹F and ³¹P NMR spectroscopy. Attempts to react the octakis(trimethylsilyl)calix[4]resorcinarene 3 and its tetrabromo derivative 4 with phosphorus trichloride and chlorodifluorophosphine were unsuccessful. The ethoxy-tethered C-methyl-octakis(trimeth-ylsilyl)calix[4]resorcinarene 5 was allowed to react with 2-chloro-1,3,5-trimethyl-1,3,5-triaza-2σ³λ³-phosphorin-4,6-dione and chlorodifluorophosphine. By substitution of all trimethylsilyl groups, the octakis(phosphorus(III))-substituted compounds 6 and 7 were formed. As for 2, dynamic behavior in solution was observed for 6 and 7, arising from the equilibrium between different conformational isomers. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:553–558, 1998     

A Theoretical Study on the Tautomerism of C-Carboxylic and Methoxycarbonyl Substituted Azoles

DFT calculations (B3LYP/6-31+G^**) have been carried out on 106 tautomers and conformers of NH-azoles bearing CO₂H and CO₂CH₃ groups. The following azoles systems have been studied: 2-substituted pyrroles, 2-substituted indoles, 2-substituted imidazoles, 2-substituted benzimidazoles, 4(5)-substituted imidazoles, 3(5)-substituted pyrazoles, 3-substituted indazoles (1H and 2H), 3,4(5)-substituted-1,2,3(5)-triazoles, 2,3(5)-substituted-1,2(3),4-triazoles, 4(5)-1,2,3,4(5)-tetrazoles. In the case of pyrazole, 3,5-disubstituted derivatives have also been computed, including four dimers.Dedicated to our friend Professor Vladimir I. Minkin on his 70th anniversary.     

Synthesis of pyrimidino[4,5-b][1,5]benzodiazepin-2-ones and pyrimidino[1,6-a]benzimidazol-1-ones from 4-ethoxycarbonylamino-1H-1,5-benzodiazpine-3-carbonitrile via 4-(2-aminoanilino)pyrimidin-2(1H)-one-5-carbonitriles

Reactions of 4-ethoxycarbonylamino-1H-1,5-benzodiazepine-3-carbonitrile (2) with aliphatic primary amines gave 1-substituted 4-(2-aminoanilino)pyrimidin-2(1H)-one-5-carbonitriles 3. Analogous reactions of 2 with aromatic primary amines afforded 2-(2′-anilino-1′-cyanovinyl)benzimidazoles 5 and 6. Upon treatment with triethylamine, 3 underwent intramolecular cyclization to give 3-substituted 5-aminopyrimidino[4,5-b]-[1,5]benzodiazepin-2(3H,11H)-ones 8 . Heating of 3 with p-toluenesulfonic acid in ethanol gave 2-substituted pyrimidino[1,6-a]benzimidazol-1(2H)one-4-carbonitriles 9 . Reactions of 2 with hydrazines were also described. Mechanistic pathways are proposed to account for the products.     

Synthese substituierter Cyclononatetraene

Synthesis of Substituted Cyclononatetraenes In the course of an exploration of possible synthetic pathways to nonafulvenes, a series of 1-substituted cyclononatetraenes (CNT) 4b–1 have been prepared in yields of about 60%. Their structures follow from spectroscopic data as well as from the quantitative valence isomerisation to 1-endo-substituted cis-3a, 7a-dihydroindenes 8 . Both all-cis-CNT⁻ 1 and cis,cis,cis,trans-CNT⁻ 2 have been used as nucleophiles. Whereas 2 is normally more nucleophilic than 1 , the yield of cyclononatetraenes 4 prepared with 2 may be reduced due to by-products such as 9 and 10 .     

Synthesis and spectral properties of substituted 4-chlorooxazoloquinolines

Summary The treatment of a mixture of linearly and angularly annelated 2-substituted oxazolo[4,5-f]quinolones (5a–c) and oxazolo[5,4-g]quinolones (6a–c) and similarly the treatment of 2-substituted oxazolo[5,4-f]quinolones (7a–c) and oxazolo[4,5-g]quinolones (8b,c) with POCl₃ afforded substituted 4-chlorooxazolo[4,5-f]quinolines (9a–c) and 2-substituted 4-chlorooxazolo[5,4-f]quinolines (10b,c), respectively. Spectral characteristics of the synthesized derivatives (¹H and¹³C NMR, IR, UV, and MS) are discussed.Dedicated to Prof.Fritz Sauter on the occasion of his 65th birthday     

Synthesis and calming activity of 6<Emphasis Type="Italic">H</Emphasis>-2-Amino-4-Aryl-6-(4-<Emphasis Type="Italic">β</Emphasis>-D-Allopyranosyloxyphenyl)-1,3-Thiazine

E-(4-β-D-Allopyranosyloxyphenyl)-1-(4-substituted phenyl)propenone derivatives (1a–g) have been synthesized by the Claisen-Schmidt condensation of helicid with 4-substituted acetophenone using 10% NaOH aqueous solution as a catalyst. 6H-2-Amino-4-aryl-6-(4-β-D-allopyranosyloxyphenyl)-1,3-thiazine (2a–g) were synthesized by the 1,4-Michael reaction of 1a–g with thiourea. The structures of all the new products were established by ¹H NMR, IR, and MS spectroscopy. Compound 2b (200 mg·kg^–1) showed better sedative-hypnotic activity, so further modification of helicid should be worthwhile.     

Nucleotides,Part LXIII,New 2-(4-Nitrophenyl)ethyl(Npe)- and 2-(4-Nitrophenyl)ethoxycarbonyl(Npeoc)-Protected 2′-Deoxyribonucleosides and Their 3′-Phosphoramidites – Versatile Building Blocks for Oligonucleotide Synthesis

A series of new base-protected and 5′-O-(4-monomethoxytrityl)- or 5′-O-(4,4′-dimethoxytrityl)-substituted 3′-(2-cyanoethyl diisopropylphosphoramidites) and 3′-[2-(4-nitrophenyl)ethyl diisopropylphosphoramidites] 52 – 66 and 67 – 82 , respectively, are prepared as potential building blocks for oligonucleotide synthesis (see Scheme). Thus, 3′,5′-di-O-acyl- and N ²,3′-O,5′-O-triacyl-2′-deoxyguanosines can easily be converted into the corresponding O⁶-alkyl derivatives 6 , 8 , 10 , 12 , 14 , and 16 by a Mitsunobu reaction using the appropriate alcohol. Mild hydrolysis removes the acyl groups from the sugar moiety (→ 9 , 11 , 13 , 15 , and 19 (via 18 ), resp.) which can then be tritylated (→ 38 – 42 ) and phosphitylated (→ 57 – 61 ) in the usual manner. N ²-[2-(4-nitrophenyl)ethoxycarbonyl]-substituted and N ²-[2-(4-nitrophenyl)ethoxycarbonyl]-O⁶-[2-(4-nitrophenyl)ethyl]-substituted 2′-deoxyguanosines 5 and 7 , respectively, are synthesized as new starting materials for tritylation (→ 28 , 35 , and 37 ) and phosphitylation (→ 54 , 56 , 70 , and 78 ). Various O⁴-alkylthymidines (see 20 – 24 ) are also converted to their 5′-O-dimethoxytrityl derivatives (see 43 – 47) and the corresponding phosphoramidites (see 62 – 66 and 79 – 82 ).     

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.     

Hydroxymethylation and aminomethylation of 6-mercaptopurine and its derivatives

Labile aminomethyl and hydroxymethyl derivatives of 6-mercaptopurine (I) (6-MP) and S⁶-acyloxymethyl-6-MP have been converted to stable acetyloxymethyl derivatives by their reaction with acetic anhydride. Analysis of the reaction products and comparison of their 'H nmr spectra and hplc chromatograms with those of acetyloxymethyl derivatives of known structures suggested 1) that the aminomethyl derivatives of 6-MP were 7-substituted derivatives, 2) that the aminomethyl derivative of S⁶-acetyloxylmethyl-6-MP was a 9-derivative, 3) that the hydroxymethyl derivative of 6-MP was a mixture of 7-substituted and S⁶,3-disubstitu-ted derivatives, and 4) that the hydroxymethyl derivative of S⁶-pivaloyloxymethyl-6-MP was a 9-substituted derivative. In addition, a previously unreported dialkyl derivative of 6-MP VI was isolated from its reaction with aminomethylating agent and characterized. Analyses of the 'H nmr spectra and hplc chromatograms of the reaction of VI with acetic anhydride suggested that VI was a 1,7-disubstituted derivative.     

Chemosensor properties of mono- and bisthioureas based on 9-anthrylmethyl-substituted alkylamines and diamines

Mono- and bisthioureas were synthesized based on N-(9-anthrylmethyl)-substituted alkylamines and diamines. Their luminescent and complexing properties were studied by the electronic, IR, and NMR ¹H spectroscopy. N-(9-Anthrylmethyl)-N-(6-{9-anthrylmethyl[(phenylamino)carbothioyl]amino}hexyl)-N′-phenylthiourea was shown to be a highly effective fluorescent chemosensor for Hg²⁺ cations.     

Dihydropyrimidines and related structures. I. N2-substituted 2-pyrimidinamines and dihydro-2-pyrimidinamines by reaction of phenylbutenones and monosubstituted guanidines

The reactions of monosubstituted guanidines 2 with phenylbutenones 7 and 10 exclusively yield N²-substituted 2-pyrimidinamines 8 and 9 . The structure of the reaction products is proved and their differing stability is discussed. Action of methyl- and benzylguanidine respectively ( 2b, c ) on 4-phenyl-3-buten-2-one ( 7 ) and of 2c on l-phenyl-2-buten-1-one ( 10 ) under atmospheric oxygen affords aromatic N²-substituted 2-pyrimidinamines 9b and c . The dihydropyrimidines 8b and c, probable intermediates of the reactions, could not be isolated. In contrast, heating of arylguanidines 2d , e with 7 leads to stable dihydropyrimidinarnines 8d and e, which can be isolated as bases. Addition of methanol to 8d yields 6-methoxy-2-pyrimidinamine 11d , boiling of 8d in DMF affords 9d . Under nitrogen, guanidine adds to 7 to yield aminopyrimidinol 13a , which is transformed by heating in benzene into pyrimidine 9a . The low stability of 8a-c is attributed to their strong basicity, the greater stability of 8d and e to their lower basicity. The structural formulae of 8d , e and 9b-d and their salts respectively were established partly ( 8e ) by nmr and partly ( 9b-d ) by comparison of the corresponding picrates with authentic samples [17].     

A Cyclodextrin Molecular Reactor for the Regioselective Synthesis of 1,5-disubstituted-1,2,3-triazoles

6^A-Deoxy-6^A-propynamido-β-cyclodextrin reacts with 4-tert-butylphenyl azide in aqueous solution, to form the 5-(aminocarbonyl)-substituted triazole in preference to the 4-(aminocarbonyl)-substituted analogue, in a ratio of 25:1. The cyclodextrin moiety templates the reaction through the formation of a host-guest complex of the dipole with the dipolarophile, controlling the regioselectivity of cycloaddition. In a control reaction under similar conditions, with propiolamide instead of the cyclodextrin derivative, 5- and 4-(aminocarbonyl)-1-(4-tert-butylphenyl)-1,2,3-triazole were formed in a ratio of 1:4. As well as reversing the regioselectivity, the cyclodextrin substituent increases the rate of cycloaddition, by at least two orders of magnitude for the reaction to give the 5-substituted cycloadduct. Even the rate of formation of the 4-substituted cycloadduct is increased by a factor of two. Less marked effects are observed with phenyl azide and 4-tert-butylbenzyl azide as dipoles.     

Alkynylhalocarbenes

(Alk-1-ynyl)chlorocarbenes (3), generated from 1,1-dihaloalk-2-ynes and 3-substituted 3-bromo-1,1,1-trichloropropanes under the action of Bu^tOK in THF at 20°C, react with excess alkali metal alkoxide4 to give 3-substituted 2-(alk-1-ynyl)oxiranes (6) in 26–78% yields, most likely as a result of insertion of carbene3 into the α-C−H bond of alkoxides4 and subsequent cyclization of the resulting 1-substituted 2-chloro-2-(alk-1-ynyl)etoxides. The yields of oxiranes6 depend on the nature of the alkali metal used to prepare alkoxides4 and on the method employed for the preparation of the latter. For Part 2, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1185–1192, June, 1998.     

Synthesis,characterization, and biological activities of some novel thienylpyrido[3′,2′:4,5]thieno[3,2-d]pyrimidines and related heterocycles

3-Cyano-5-ethoxycarbonyl-6-methyl-4-(2′-thienyl)-pyridine-2(1H)-thione ( 1 ) is synthesized and reacted with chloroacetamide or chloroacetonitrile to give 3-amino-5-ethoxycarbonyl-6-methyl-4(2′-thienyl)-thieno[2,3-b]pyridine-2-carboxamide 3a or its 2-carbonitrile analog 3b , respectively. Cyclocondensation of 3a with triethylorthoformate produced the corresponding pyridothienopyrimidineone 4 , which on heating with phosphorus oxychloride gave 4-chloropyrimidine derivative 5 . Compound 5 was used as key intermediate for synthesizing compounds 6 , 9 , 10 , 11 , and 12 upon treatment with some nucleophilic reagents such as thiourea, 5-phenyl-s-triazole-3(1H)-thione, piperidine, morpholine, or hydrazine hydrate, respectively. Reaction of pyridothienopyrimidinethione 6 with N-(4-tolyl)-2-chloroacetamide or ethyl bromoacetate afforded the corresponding S-substituted methylsulfanylpyrimidines 7 or 8 . The condensation of 3b with triethylorthoformate gave azomethine derivative 13 , which was reacted with hydrazine hydrate to give ethyl 3-amino-3,4-dihydro-4-imino-7-methyl-9-(2′-thienyl)pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine-8-carboxylate ( 14 ). Compounds 12 and 14 were used as precursors for synthesizing other new thienylpyridothienopyrimidines as well as isomeric thienyl-s-triazolopyridothieno- pyrimidines. All synthesized compounds were characterized by elemental and spectral analyses such as IR, ¹H NMR, and ¹³C NMR. In addition, majority of synthesized compounds were tested for their antifungal activity against five strains of fungi. Moreover, compounds 3a , 5 , 6 , 8 , and 22 were screened for their anticancer activity against HEPG-2 and MCF-7 cell lines.     

Synthesis of 6-substituted 3-cyano-5-nitropyridine-2(1H)-thiones

The reactions of 1-substituted 2-nitro-3-phenylaminoprop-2-en-1-ones with cyanothioacetamide afforded the corresponding 6-substituted 3-cyano-5-nitropyridine-2(1H)-thiones, which were used for the synthesis of 6-substituted 3-cyano-2-methylthio-5-nitropyridines and 7-substituted 4-hydroxy-8-nitropyrido[2",3":4,5]thieno[2,3-b]pyridin-2(1H)-ones.     

Mass spectrometry of homoadamantane derivatives

Homoadamantane derivatives can be divided into two groups according to their mass spectra. To the first group belong compounds with electron attracting substituents (COOH, CI, COOCH₃, Br); compounds with electron releasing substituents (OCH₃, OH, NH₃, NHCOCH₃) constitute the second group. The most characteristic feature of the first group compounds is the splitting off of the substituent. The hydrocarbon fragment [C₁₁H₁₇]⁺ thus formed then loses olefin molecules with the formation of corresponding ionic species C_11?nH_17?2n. The 3-substituted compounds of this group undergo thermal Wagner-Meerwein type rearrangements into adamantane derivatives, resulting in the [C₁₀H₁₅]⁺ (m/e 135) ion formation; this is the main difference between 1- and 3-substituted homoadamantanes. The series of [C_nH_2n?6X]⁺ ions (where X = OCH₃, OH, NH₂, NHCOCH₃, n = 6 to 10) are characteristic of the mass spectra of the second group compounds, the ion [C₆H₆X]⁺, [M ? C₅H₁₁]⁺ being the most abundant. The intensity ratio of [M ? C₅H₁₁]⁺ to [M ? C₄H₉]⁺ ions is 10:1 for 1-substituted and 3:1 for 3-substituted compounds of this group, allowing the location of the substituent. Some individual features of the spectra are also reported.     

[1,3]Dioxolo[5,6][1]benzothieno[2,3-c]-quinolin-6(5H)-ones

Summary The reaction of 3,4-methylenedioxycinnamic acid (1) with thionyl chloride resulted in the formation of 7-chlorothieno[2,3-f]-1,3-benzodioxole-6-carbonyl chloride (2) and cinnamoyl chloride (3). Subsequent reaction of the former withp-substituted anilines led to the formation of 7-chloro-N-(p-substituted phenyl)-thieno[2,3-f]-1,3-benzodioxole-6-carboxamides (4a–c) which on photocyclization afforded 2-substituted [1,3]dioxolo[5,6][1]benzothieno[2,3-c]quinolin-6(5H)-ones (5a–c) in fairly good yields and high purity. The structures have been confirmed by IR,¹H NMR, and analytical methods.Accepted for presentation at the Hong Kong International Symposium on Heterocyclic Chemistry (August 13–16, 1995)     

Reaction of Methylmalonyl Dichloride with Unsaturated Carboxamides

Methylmalonyl dichloride reacts with (2E)-3-phenylacrylamides and (2E)-3-(2-furyl)acrylamide to give the corresponding E-isomeric 2-substituted 4-hydroxy-5-methyl-6H-1,3-oxazin-6-ones. The reaction of methylmalonyl dichloride with acrylamide afforded N-(3-chloropropionyl)-2-methylmalonamic acid. The structure of the products was confirmed by the ¹H and ¹³C NMR, IR, and UV spectra.     

Synthesis,structural and conformational study of some amides derived from 3,7-dimethyl-9-amino-3,7-diazabicyclo[3.3.1]nonane-9-carboxamide

A series of 3,7-dimethyl-9-amino-3,7-diazabicyclo[3.3.1]nonane-9-carbonitrile and 3,7-dimethyl-9-amino-3,7-diazabicyclo[3.3.1]nonane-9-carboxamide N-substituted have been synthesized and studied by ¹ H and ¹³C nmr spectroscopy and the crystal structure of 3,7-dimethyl-9-benzylamino-3,7-diazabicyclo[3.3.1]nonane-9-carboxamide dihydrochloride ( IVb· 2HCl) has been determined by X-ray diffraction. The compounds studied display in deuteriochloroform, dimethyl sulfoxide-d₆ and methanol-d₄ the same preferred flattened chair-chair conformation with the methyl groups in equatorial position. The carboxamido group lies in a plane nearly perpendicular to the bispidine skeleton. The conformation and protonation sites of IVb· 2HCl in the crystal state and in deuterium oxide solution are discussed.