Coordination polymers. XIII. Synthesis and investigation of polymers obtained by the reaction of maleic acid with ZnO

In some cases metal dicarboxylates can be considered as polymers. Formation of crystalline or amorphous polymer depends on the type and ratio of the metal ion to the carboxylate ligand and on the preparation conditions. The “polymer salt” synthesized by the reaction of ZnO and maleic acid shows special feature due to the cis configuration of the dicarboxylic acid. The polymer prepared in a water medium has a fibrillar morphology with a helical structure which is changed by heat treatment: a molecular rearrangement takes place which leads finally to amorphous polymer. The reaction of ZnO and fumaric acid (trans configuration) results in monocrystals containing crystal water or, after heat treatment, in powderlike polymer.     

N-substitution in the 2-amino- and 2,7-diaminophenoxazin-3-one ring system. Application to the preparation of actinomycin D analogs

A method is described for the direct N²-monoalkylation of the 2-aminophenoxazin-3-one system by treatment with dimethylsulfonium methylide in DMSO-THF, which acts as a base by abstracting a proton from the 2-amino function to form a stabilized anion, which is then alkylated by reaction with an alkyl halide. Selective N⁷-monoalkylation of the 2,7-diaminophenoxazin-3-one system can be accomplished by reaction with aromatic aldehydes in glacial acetic acid to give Schiff bases, which are then reduced with dimethylamine borane. These reactions have been applied to the preparation of N²-benzyl- and 7-benzylaminoactinomycin D.     

Study on the murexide reaction. V

Although the reaction of caffeine with hydrogen peroxide/hydrochloric acid or nitric acid and then with ammonia has been known to give a purple coloration (Murexide reaction), the use of hydrazine instead of ammonia is found to provide no purple coloration. The reaction of caffeine with hydrogen peroxide/hydrochloric acid and then with hydrazine hydrate afforded a yellow reaction mixture, from which 4-methyl-6-(N-methylcarbamoyl)-3,5-dioxo-2,3,4,5-tetrahydrotriazine 9 , oxalyl hydrazide 10 and hydroxylamine hydrochloride were isolated. The reaction of caffeine with nitric acid and then with hydrazine hydrate furnished a yellow reaction mixture, from which 8-amino-1,3,7-trimethyl-2,6-dioxo-1H,3H,7H-xanthine 11, 9 and hydroxylamine nitrate were isolated. Compound 9 was clarified to be produced from 3-hydroxy-4,6-dimethyloxazolo[4,5-d]pyrimidine-2,5,7(3H,4H,6H)-trione 3 and 1,3-dimethylalloxan 7 by the ring transformation with hydrazine.     

Novel heterocycles. 4. Synthesis of the pyrido[2,3-c]-1,2-thiazine ring system

The reaction of 2-chloronicotinonitrile with N-methylmethanesulfonamide and subsequent treatment with base furnished the novel pyrido[2,3-c]-1,2-thiazine ring system 7 . Spectrally, it was determined that the predominant tautomer in solution was the 4-amino form 7a . Acidic hydrolysis of 7 furnished the 4-oxo tautomer 8b , compound 8b was alkylated on oxygen with 1-bromopentane in the presence of sodium hydride. Reaction of 8b with isocyanates occurs at the 3 position to produce carboxanilides 10 . Spectral characteristics of these compounds are also discussed.     

Dediazoniations of arenediazonium ions. Part 26 Influence of Substituents on the Formation of Benzoic Acids in Reactions of Aryl-Cation-Type Intermediates with CO

The N₂-molecule-aryl-cation pair formed as the first intermediate in dediazoniations of arenediazonium ions can be trapped with CO in H₂O with formation of the corresponding arenecarboxylic acids. This reaction is considered as a model for the reverse of dediazoniation, since CO is isoelectronic with N₂. The evaluation of the yields of arenecarboxylic acids formed from substituted benzenediazonium ions using Taft's dual substituent parameter treatment demonstrates that the field reaction constant p_F and the resonance reaction constant p_R are positive and negative, respectively, as expected for a reaction which corresponds electronically to the addition of N₂ to aryl cations.     

Pyrimidones. 2. Synthesis and reactions of 2-chloropyrimidines

The treatment of 1-alkyl-5-aryl and 1-alkyl-4,5-diaryl-2-(1H)pyrimidones with phosphorus oxychloride and phosphorus pentachloride resulted in chlorination and dealkylation to furnish 2-chloro-5-aryl (or 4,5-diaryl)-pyrimidines. These chlorpyrimidines were reacted with a variety of nitrogen, oxygen, sulfur, and carbon nucleophiles to produce the corresponding 2-substituted pyrimidines. In the case of phenyllithium, attack occurred at the 4-position of the pyrimidine ring yielding 11 . Triazolopyrimidine 9 was synthesized via the treatment of 2d with hydrazine followed by reaction with triethyl orthoformate.     

Novel heterocycles. 9. Synthesis of the benzofuro[2,3-c][1,2]thiazine ring system

The treatment of 2-coumaranone with the Vilsmeier reagent affords three products: 2-chloro-3-benzofurancarboxaldehyde ( 3 ), 3-dimethylaminomethylene-2-(3H)benzofuranone ( 4 ), and 3-dimethylaminomethylene-2,3-dihydro-2-oxo-6-benzofurancarboxaldehyde ( 5 ). Both 4 and 5 are isolated as a mixture of E and Z isomers. The reaction of 3 with the anion of N-methylmethanesulfonamide affords the title compound 1-methyl-1H-benzofuro[2,3-c][1,2]-thiazine 2,2-dioxide ( 6 ). Spectral data is also discussed.     

Experiments on the total synthesis of Lysolipin I. Part II. Michael addition of 1,3-cyclohexanedione to quinone acetals

Base-catalyzed reaction of 1,3-cyclohexanedione ( 3 ) with the quinone monoacetals 4 and 7 leads to the polycyclic products 5 and 8 , respectively, and in the case of 4 to variable amounts of dibenzofuranone 6 . The 2-arylcyclohexanedione 9 , on the other hand, is isolated from the reaction of 3 and bisacetal 11 catalyzed by ZnCl₂ (Scheme 2). Treatment of the adduct 8 with (CH₃O)₂SO₂/K₂CO₃ results in cleavage of teh heterocyclic ring by a retro-Michael reaction affording teh liable enone 23 which was further transformed to 24 by selective hydrogenation. The 8-acetoxydibenzofuranone 22 is obtainable from 8 by acid treatment and acetylation (Scheme 4). The reactions of the silylenol ethers 27 and 35 with quinone monoacetals were very complex (Scheme 6). The desired arylcyclohexanone derivatives 28 and 36 were formed in very low yields. Under certain conditions (elevated temperature or strong Lewis acids as catalysts), single-electron transfer or addition to the ene-acetal rather than to the enone function of the quinone monoacetals became predominant. In connection with this study, the sensitive 2-methoxy-p-benzoquinone monoacetals 15 (Scheme 3) and 29 (Scheme 6) have been prepared and characterized.     

On the photodecomposition of chlorophyll in vitro. I. Reaction rates

Abstract— Chlorophyll solutions are irreversibly bleached by light in the presence of oxygen. The action spectra parallel the absorption spectra for both chlorophyll a and b. The reaction is of second order with a Q₁₀ of 1.26. The reaction rates for chlorophylls a and b are of the same order of magnitude. Depending upon the light source, the initial rate for chlorophyll a is slightly higher, by a factor of 1.15 to 1.30. The rate for pheophytin is lowe 3 by several orders of magnitude. No pheophytin has been detected in the reaction products of the irradiated chlorophyll solutions in the absence of water.     

Chemistry of Peri-condensed pyrroles. Synthesis of 4H-naphtho[1,4-def]carbazole. A new route to nitrotriphenylenes

Reaction of 1-nitrotriphenylene ( 7a ) with triethylphosphite (Cadogan reaction) produces 4H-naphtho[1,4-def]carbazole, a likely component of fossil fuels. Surprisingly 7a and its 2-isomer are obtained from treatment of triphenylene with sulfuric acid/trifluoroacetic anhydride in nitromethane. Correlation between ultraviolet spectra and substitution reactions in peri-condensed pyrroles and thiophenes is presented.     

Novel protecting groups. III. A study of the reaction of 2-picolyl 1-oxide derivatives with acetic anhydride

2-Picolyl 1-oxides (I-VIII) were prepared and the reaction of I-VII with acetic anhydride was followed by the gas chromatography. In this reaction, the increasing order of the rate of disappearance of the 2-pieolyl 1-oxide derivatives was found to be IV>III>VII>I>VI>II>V. Under comparable conditions, a half-life of VIII is midway between that of I and VI. The 2-picolyl 1-oxide group was found to be potentially useful for the blocking of hydroxyl functions of phosphates (viz., VIII), although ca. 4% of the organic phosphate remained unblocked after the deblocking procedure (acetic anhydride treatment and subsequent hydrolysis).     

Fused indoles. 2. Synthesis and reactions of imidazo[1,2-a]- and pyrimido[1,2-a]-indoles

The alkylation of 2-chloroindole-3-carboxaldehyde ( 1 ) and 3-acetyl-2-chloroindole ( 5 ) with 3-chloro-N,N-dimethyl-1-propylamine, 3-chloro-N,N-diethyl-1-propylamine and 2-chloro-N,N-dimethyl-1-ethylamine is described. Following alkylation, demethylation occurs and furnishes imidazo[1,2,-a]- and pyrimido[1,2-a]indoles ( 3a,6,8,10 ). Pyrimido-indole 3a , on treatment with lithium aluminum hydride, furnishes the bis-indole 12 . Analogous reaction with diborane affords the reduced product 14 , while reaction with methyllithium yields the deformylated product 13 . Spectral data of the resulting compounds are also discussed.     

New Method for the Generation and Trapping of 1-Azabicyclo[1.1.0]butane. Application to the Synthesis of 1,3-Dinitroazetidine

1-Azabicyclo[1.1.0]butane (1) has been prepared via a two-step, one-pot procedure that involves (i) reaction of a heptane solution of allylamine with N-chlorosuccinimide at 0 °C followed by (ii) codistillation of the product from basic solution along with heptane-octane. Compound 1 thereby obtained was extracted from the distillate by using cold aqueous NaNO₂. Subsequent treatment of the aqueous extract with cold concentrated aqueous HCl afforded N-nitroso-3-nitro-azetidine (4) in 5.5% yield. Oxidation of 4 with 100% HNO3 produced N,3-dinitroazetidine (5, 90%). This reaction sequence constitutes a formal synthesis of 1,3,3-trinitroazetidine (TNAZ), an important energetic material.     

Carbocyclische Verbindungen aus Monosacchariden. II. Umsetzungen in der Mannosereihe

Carbocyclic compounds from monosaccharides. II. Transformations in the mannose series Upon treatment with Zn in refluxing aqeous ethanol or butanol, the anomeric mannopyranosides 11 and 14 yielded the aldehyde 15 which was subjected (via its N-methyl-nitrone) to an intramolecular nitrone-olefine cycloaddition leading diastereoselectively to 18 in a yield of 64% from 14 . Minor products of this reaction sequence were the compounds 19 , 20 and 21 . Similarily, the easily accessible unsaturated furanose 26 , upon treatment with N-methyl-hydroxylamine gave the isoxazolidines 27 (84%) and 28 (3%), thus showing that a free 4-hydroxy group is not detrimental to this intramolecular nitrone-olefin cycloaddition. The configuration of 18 , 27 and 28 (resp. 29 ) were determined by spectroscopic means; that of 27 was further proven by transformation into the compound 31 , of which an X-ray analysis was performed.     

Novel heterocycles. 10. Reactions of 1,3,2-benzodiazaphosphorin-4(1H)-one 2-oxides

Reactions of 1,3-disubstituted-2,3-dihydro-1,3,2-benzodiazaphosphorin-4 (1 H)-one 2-oxides ( 1 ) with various electrophiles were investigated. The treatment of 1 with aldehydes in the absence of a basic catalyst directlyafforded alcohols 7a-h in good yield. The product from the reaction of 1 with chloral, on treatment with sodium hydride, resulted in the formation of a dichloroepoxide ( 8 ). When 1 was allowed to react with isocyanates or isothiocyanates in the presence of triethylamine, amides 10a-e and thioamide 11 were produced in good yield. Compounds 1a and 1b were readily halogenated on their phosphorus atom by treatment with either carbon tetrachloride or carbon tetrabromide and triethylamine. The P-chloro compound 12a reacted with ethanol to furnish the P-ethoxy derivative 13 and, in an attempt to react 12a with bis (2-chloroethyl) amine, anhydride 14 was formed in high yield. Spectral data for the majority of the products are also discussed.     

Syntheses with nitriles. 60. Preparation of 4-amino-5-cyano-6-phenylpyrimidines from 2-amino-1,1-dicyano-2-phenylethene

The reaction of 2-amino-1,1-dicyanobut-1-ene and 2-amino-1,1-dicyano-2-phenylethene, respectively, with N,N-dimethylformamide dimethylacetal provided the corresponding (N,N-dimethylaminomethylene)amino derivatives. 2-[(N,N-Dimethylaminomethylene)amino]-1,1-dicyano-2-phenylethene was converted into 4-amino-5-cyano-6-phenylpyrimidines by treatment with primary aliphatic and aromatic amines. The structure of the reaction products was confirmed by ¹³C nmr spectroscopy.     

The cycloaddition of ethylene to butene-2. I. Stereochemistry of the reaction

The rate of the thermal cycloaddition of ethylene to cis and trans butene-2 has been measured at 693°K and at pressures of about 12 atmospheres. The ratio of trans- to cis-1,2-dimethylcyclobutane from the reaction of trans-butene-2 with ethylene was 5.1, obtained from the initial rates of formation of the products. Similarly, the ratio of cis- to trans-1,2-dimethyl-cyclobutane from the reaction of cis-butene-2 with ethylene was 2.8. The results show that the cycloaddition reactions are the reverse of the decomposition reactions of the dimethyl-cyclobutanes and may be interpreted in terms of a biradical intermediate. Several ratios of rate constants have been measured as well as the rate constants for the reaction of the olefins to form the intermediate biradical.     

Photoinitiation. V. Effect of medium polarity on the acrylonitrile polymerization photoinitiated by naphthalene

The heterogeneous polymerization of acrylonitrile photoinitiated by naphthalene is influenced by the polarity of the reaction medium. The rate of initiation increases with the increasing dielectric strength of the reaction medium. A similar trend is observable for Stern–Volmer constants of naphthalene fluorescence quenching by acrylonitrile. The ratio k_p/k_t^1/2 of the rate constant for propagation and termination reactions is not influenced by a change in the polarity of the reaction medium. The effect of viscosity on the value of k_p/k_t^1/2 known for polymerization in a homogeneous medium was not observed in the reaction systems studied.     

Polycondensed nitrogen heterocycles. Part 19. Pyrrolo[1,2-f]phenanthridines by pschorr-type cyclization brought about by hypophosphorous acid

Pyrrolo[1,2-f]phenanthridines were prepared in good yields by the diazotization in acetic acid of the amines la,b and subsequent treatment with hypophosphorous acid. The necessity for hypophosphorous acid in the reaction was demonstrated.     

Preparation of polyamides via the phosphorylation reaction. X. A study of higashi reaction conditions

We report a study of the conditions of the phosphorylation reaction for the preparation of aromatic polyamides using the Higashi reaction medium. For poly(p-phenylene terephthalamide) (PPD-T), the optimum conditions are: reaction temperature, 115°C; monomer concentration, C = 0.083 mol/L; and ratio of triphenyl phosphite (TPP) to monomer, 2.0. These optimum conditions produce PPD-T having η_inh = 6.2 dL/g. At temperatures of 120°C and above PPD-T precipitates from the reaction mixture, leading to lower molecular weights. At lower temperatures the reaction mixture gels, and the gel time decreases with increasing reaction temperature. However, polycondensation continues in the gel state. Monomer concentrations C = 0.10 mol/L and above produce precipitation and yield polyamides of lower molecular weight. For the preparation of poly(p-benzamide) (PBA), the optimum ratio of TPP to monomer is 0.6 for either p- aminobenzoic acid or N-4-(4′-aminobenzamido)benzoic acid. In the former case the inherent viscosity of polymer prepared at 115°C showed little dependence upon the concentration of the monomer. The highest value, η_inh = 1.8 dL/g, was obtained with C = 0.40 mol/L and a TPP/monomer ratio of 0.6. However, for the same TPP/monomer ratio, the monomer containing a preformed amide linkage, N-4-(4′-aminobenzamido)benzoic acid, gave PBA with η_inh = 4.6 dL/g when the monomer concentration is 0.33 mol/L. This is the highest value reported for PBA using the phosphorylation reaction. In A?A + B?B polycondensation, examples in which one of the monomers contained one or two preformed amide linkages produced polyamides having η_inh = 7.8 and 8.9 dL/g, respectively.