IIa IIc Research Articles

U2 snRNA Conformation is Regulated by Cus2 to Facilitate Dead-Box Protein Loading

The spliceosome undergoes dynamic changes in composition and conformation during assembly and splicing. We are interested in studying how the spliceosomal U2 snRNP loads onto pre-mRNA branchsites during assembly. This involves multiple conformations of the U2 snRNA (stem IIa vs. stem IIc), the Prp5 DEAD-box protein, and the Cus2 RRM protein. Our results show that Cus2 binds to WT or stem IIa stabilized model RNAs but not to stem IIc. In contrast, Prp5 binds indiscriminately to all three types of U2 RNA and each equally stimulates Prp5's ATPase. Prp5 appears to either displace or out compete Cus2 for U2 RNA binding in an ATP-independent process. Using single molecule FRET, we show the U2 core RNA is dynamic with interconverting populations of high- (likely stem IIc) and mid-FRET states (likely stem IIa). Addition of Cus2 depletes the high-FRET state, consistent with conformational selection of U2 stem IIa by Cus2. Together, our data support spliceosomal proteins acting in concert to facilitate loading of the DEAD-box onto a particular RNA structure. This represents a new paradigm for protein:RNA interactions that is distinct from ordered binding of structure specific RNA-binding proteins (i.e., ribosome assembly) or from positional control of DEAD-box protein loading during exon junction complex formation.

Analytic Theory of Finite Asymptotic Expansions in the Real Domain. Part II-A: The Factorizational Theory for Chebyshev Asymptotic Scales

This paper, divided into three parts (Part II-A, Part II-B and Part II-C), contains the detailed factorizational theory of asymptotic expansions of type (?) , , , where the asymptotic scale , , is assumed to be an extended complete Chebyshev system on a one-sided neighborhood of . It follows two pre-viously published papers: the first, labelled as Part I, contains the complete (elementary but non-trivial) theory for ; the second is a survey highlighting only the main results without proofs. All the material appearing in §2 of the survey is here reproduced in an expanded form, as it contains all the preliminary formulas necessary to understand and prove the results. The remaining part of the survey—especially the heuristical considerations and consequent conjectures in §3—may serve as a good introduction to the complete theory.

Block the function of nonmuscle myosin II by blebbistatin induces zebrafish embryo cardia bifida.

Nonmuscle myosin II (NM II) is the name given to the multi-subunit protein product of three genes encoding different nonmuscle myosin heavy chains including NM II-A, NM II-B, and NM II-C. Blebbistatin is a small molecule that has been shown to be a relatively specific inhibitor of NM II. Blocking the function of NM II by blebbistatin induces zebrafish embryo cardia bifida at a dose-dependent manner. In situ hybridization analysis with ventricular marker ventricular myosin heavy chain (vmhc) and atrial marker atrial myosin heavy chain (amhc) showed each of the heart contained both distinct atria and ventricle. However, the cardia bifida embryos had highly variable distance between two separate ventricles. We also provided evidence that time window from 12 to 20 h post fertilization (hpf) is necessary and sufficient for cardia bifida formation caused by blebbistatin treatment. Expression of spinster homolog 2 (spns2) was decreased in blebbistatin-treated embryos, suggesting the cardia bifida phenotype caused by NM II inhibition was relevant to precardiac mesoderm migration defects. Through in situ hybridization analysis, we showed that foxa1 was expressed in endoderm of blebbistatin-treated embryos at 24-hpf stage, suggesting the endoderm formation is normal in cardia bifida embryos caused by blebbistatin treatment. In addition, we demonstrated that blebbistatin treatment resulted in morphology alteration of zebrafish cardiomyocytes in vivo and neonatal mouse cardiomyocytes in vitro.

Life without double-headed non-muscle myosin II motor proteins.

Non-muscle myosin II motor proteins (myosin IIA, myosin IIB, and myosin IIC) belong to a class of molecular motor proteins that are known to transduce cellular free-energy into biological work more efficiently than man-made combustion engines. Nature has given a single myosin II motor protein for lower eukaryotes and multiple for mammals but none for plants in order to provide impetus for their life. These specialized nanomachines drive cellular activities necessary for embryogenesis, organogenesis, and immunity. However, these multifunctional myosin II motor proteins are believed to go awry due to unknown reasons and contribute for the onset and progression of many autosomal-dominant disorders, cataract, deafness, infertility, cancer, kidney, neuronal, and inflammatory diseases. Many pathogens like HIV, Dengue, hepatitis C, and Lymphoma viruses as well as Salmonella and Mycobacteria are now known to take hostage of these dedicated myosin II motor proteins for their efficient pathogenesis. Even after four decades since their discovery, we still have a limited knowledge of how these motor proteins drive cell migration and cytokinesis. We need to enrich our current knowledge on these fundamental cellular processes and develop novel therapeutic strategies to fix mutated myosin II motor proteins in pathological conditions. This is the time to think how to relieve the hijacked myosins from pathogens in order to provide a renewed impetus for patients' life. Understanding how to steer these molecular motors in proliferating and differentiating stem cells will improve stem cell based-therapeutics development. Given the plethora of cellular activities non-muscle myosin motor proteins are involved in, their importance is apparent for human life.

ChemInform Abstract: Synthesis of 6H‐Pyrrolo[2,3,4‐gh]perimidines from Naphthalene‐1,4,8‐triamine.

The importance of indole derivatives as biologically active compounds is difficult to overestimate. Benzo[c,d]indoles are not an exception; for example, efficient inhibitors of thymidylate synthase were found among compounds of this series [1]. The present communication describes the synthesis of fused benzo[c,d]indole derivatives, 6H-pyrrolo[2,3,4-gh]perimidines IVa–IVc, from naphthalene-1,4,8-triamine (I) and 1,3,5-triazines IIa–IIc. We previously showed that 1,3,5-triazine in polyphosphoric acid (PPA) acts as efficient formylating and acylating agent [2–5], in particular toward naphthylamines [5]. Therefore, it may be expected that the use of 1,3,5-triazine should ensure convenient synthesis of pyrroloperimidines IVa–IVc. In fact, by heating triamine I with triazines IIa–IIc in PPA first at 80–90°C and then at 130–140°C we obtained the corresponding pyrroloperimidines IVa–IVc in 38–48% yield. The reaction is likely to involve intermediate formation of aminoperimidines IIIa–IIIc. Unlike the known procedure [6], the proposed method requires no preliminary preparation and acylation of perimidines. Furthermore, the key step in the known procedure [6] is the Schmidt reaction utilizing sodium azide in acid medium, and there exists a risk of evolution of toxic and explosive hydrazoic acid. The procedure proposed by us is free from the said disadvantage.

Possible involvement of altered expression of BDNF exon II gene and specific dopamine receptors in simvastatin induced beneficial effects in depression

Background The up regulation of central BDNF gene expression has been suggested in the treatment of major depression. Chronic administration of dopaminergic agents activates the function of CREB which results into the up regulation of the BDNF gene expression. Statin therapy is associated with a reduced risk of depression and could be of therapeutic potential for major depression. Materials and methods We have examined a possible link amongst simvastatin, bromocriptine, haloperidol and levodopa in accordance with BDNF exon II gene expression using RT-PCR method in mice treated with standard paradigm of chronic mild stress procedure for 14 days. We specifically determined if the oral administration of simvastatin would affect the efficacy of bromocriptine, haloperidol or levodopa in mediating the regulation of the BDNF exon II gene expression. Results The results of RT-PCR method revealed the differential expression patterns for the expression of BDNF exon II gene in brain of mouse by indicating the three different bands, as evidenced previously to be the three different exon II transcript variants in mouse namely BDNF IIA, BDNF IIB and BDNF IIC. Mice treated with bromocriptine or levodopa in combination with simvastatin for 14 days could synergize the up regulation of for the expression of specific BDN Fe xon II transcript as compared to simvastatin alone whereas the mice treated with haloperidol in combination with simvastatin for 14 days could abolish the for the expression of up regulation of specific BDNF exon II transcript compared to simvastatin alone. Conclusion

The impact of severity of hypertension on auditory brainstem responses

Background: Auditory brainstem response is an objective electrophysiological method for assessing the auditory pathways from the auditory nerve to the brainstem. The aim of this study was to correlate and to assess the degree of involvement of peripheral and central regions of brainstem auditory pathways with increasing severity of hypertension, among the patients of essential hypertension. Method: This study was conducted on 50 healthy age and sex matched controls (Group I) and 50 hypertensive patients (Group II). Later group was further sub-divided into - Group IIa (Grade 1 hypertension), Group IIb (Grade 2 hypertension), and Group IIc (Grade 3 hypertension), as per WHO guidelines. These responses/potentials were recorded by using electroencephalogram electrodes on a root-mean-square electromyography, EP MARC II (PC-based) machine and data were statistically compared between the various groups by way of one-way ANOVA. The parameters used for analysis were the absolute latencies of Waves I through V, interpeak latencies (IPLs) and amplitude ratio of Wave V/I. Result: The absolute latency of Wave I was observed to be significantly increased in Group IIa and IIb hypertensives, while Wave V absolute latency was highly significantly prolonged among Group IIb and IIc, as compared to that of normal control group. All the hypertensives, that is, Group IIa, IIb, and IIc patients were found to have highly significant prolonged III-V IPL as compared to that of normal healthy controls. Further, intergroup comparison among hypertensive patients revealed a significant prolongation of Wave V absolute latency and III-V IPL in Group IIb and IIc patients as compared to Group IIa patients. These findings suggest a sensory deficit along with synaptic delays, across the auditory pathways in all the hypertensives, the deficit being more markedly affecting the auditory processing time at pons to midbrain (IPL III-V) region of auditory pathways among Grade 2 and 3 hypertensives. Conclusion: Hence, we conclude there has been greater involvement of pontomesenchymal region with the increasing severity of the disease.

Characterization of Three Full-length Human Nonmuscle Myosin II Paralogs

Nonmuscle myosin IIs (NM IIs) are a group of molecular motors involved in a wide variety of cellular processes including cytokinesis, migration, and control of cell morphology. There are three paralogs of the NM II heavy chain in humans (IIA, IIB, and IIC), each encoded by a separate gene. These paralogs are expressed at different levels according to cell type and have different roles and intracellular distributions in vivo. Most previous studies on NM II used tissue-purified protein or expressed fragments of the molecule, which presents potential drawbacks for characterizing individual paralogs of the intact protein in vitro. To circumvent current limitations and approach their native properties, we have successfully expressed and purified the three full-length human NM II proteins with their light chains, using the baculovirus/Sf9 system. The enzymatic and structural properties of the three paralogs were characterized. Although each NM II is capable of forming bipolar filaments, those formed by IIC tend to contain fewer constituent molecules than those of IIA and IIB. All paralogs adopt the compact conformation in the presence of ATP. Phosphorylation of the regulatory light chain leads to assembly into filaments, which bind to actin in the presence of ATP. The nature of interactions with actin filaments is shown with different paralogs exhibiting different actin binding behaviors under equivalent conditions. The data show that although NM IIA and IIB form filaments with similar properties, NM IIC forms filaments that are less well suited to roles such as tension maintenance within the cell.

Synthesis of 6H-Pyrrolo[2,3,4-gh]perimidines from naphthalene-1,4,8-triamine

The importance of indole derivatives as biologically active compounds is difficult to overestimate. Benzo[c,d]indoles are not an exception; for example, efficient inhibitors of thymidylate synthase were found among compounds of this series [1]. The present communication describes the synthesis of fused benzo[c,d]indole derivatives, 6H-pyrrolo[2,3,4-gh]perimidines IVa–IVc, from naphthalene-1,4,8-triamine (I) and 1,3,5-triazines IIa–IIc. We previously showed that 1,3,5-triazine in polyphosphoric acid (PPA) acts as efficient formylating and acylating agent [2–5], in particular toward naphthylamines [5]. Therefore, it may be expected that the use of 1,3,5-triazine should ensure convenient synthesis of pyrroloperimidines IVa–IVc. In fact, by heating triamine I with triazines IIa–IIc in PPA first at 80–90°C and then at 130–140°C we obtained the corresponding pyrroloperimidines IVa–IVc in 38–48% yield. The reaction is likely to involve intermediate formation of aminoperimidines IIIa–IIIc. Unlike the known procedure [6], the proposed method requires no preliminary preparation and acylation of perimidines. Furthermore, the key step in the known procedure [6] is the Schmidt reaction utilizing sodium azide in acid medium, and there exists a risk of evolution of toxic and explosive hydrazoic acid. The procedure proposed by us is free from the said disadvantage.

Reactions of spiro[2.3]hexane-5-carbonyl chloride with phosphorus(III) acids esters

We have previously shown that the reaction of bicyclo[4.1.0]heptane-7-carbonyl chloride with medium esters of phosphorous and arylphosphonous acids occurs with the retention of the small carbocycle [1]. In continuation of this work it is interesting to study the behavior of carbonyl compounds of spirohexane series in the Arbuzov reaction [2]. Due to the high energy strain of these spiranes one could expect unusual reaction course affording new types of organophosphorus compounds. We found that spiro[2.3]hexane-5-carbonyl chloride I reacts readily with phosphorous and arylphosphonous acids esters. When an equimolar ratio of reagents was used under mild conditions (0–20°C), the attack of the P-nucleophiles occurs on the carbon atom of the carbonyl group. As a result, the reaction produces dialkyl spiro[2.3]hexane-5-carbonyl phosphonates IIa–IIc or alkylarylspiro[2.3]hexane-5-carbonyl phosphinates IId–IIf. DOI: 10.1134/S1070363213060303

Nonmuscle Myosin II Is Required for Internalization of the Epidermal Growth Factor Receptor and Modulation of Downstream Signaling

Ligand-induced internalization of the epidermal growth factor receptor (EGFR) is an important process for regulating signal transduction, cellular dynamics, and cell-cell communication. Here, we demonstrate that nonmuscle myosin II (NM II) is required for the internalization of the EGFR and to trigger the EGFR-dependent activation of ERK and AKT. The EGFR was identified as a protein that interacts with NM II by co-immunoprecipitation and mass spectrometry analysis. This interaction requires both the regulatory light chain 20 (RLC20) of NM II and the kinase domain of the EGFR. Two paralogs of NM II, NM II-A, and NM II-B can act to internalize the EGFR, depending on the cell type and paralog content of the cell line. Loss (siRNA) or inhibition (25 μm blebbistatin) of NM II attenuates the internalization of the EGFR and impairs EGFR-dependent activation of ERK and AKT. Both internalization of the EGFR and downstream signaling to ERK and AKT can be partially restored in siRNA-treated cells by introduction of wild type (WT) GFP-NM II, but cannot be restored by motor mutant NM II. Taken together, these results suggest that NM II plays a role in the internalization of the EGFR and EGFR-mediated signaling pathways.

Angiotensin converting enzyme (ACE D/I) polymorphism and its relation to liver fibrosis progression in Egyptian patients with chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is a global health problem in Egypt and causes different liver disease spectrum. Evidence indicates that angiotensin I converting enzyme (ACE) gene polymorphism may play a role in determining disease progression. We aimed to determine the association of ACE gene I/D polymorphism with ACE serum levels and to examine the association between different I/D genotypes with the severity of hepatic fibrosis in chronic HCV infected Egyptian patients. Thirty controls and 90 HCV infected patients participated in the study, patients were subgrouped by Ishak stage of fibrosis into subgroup IIa (n=30; fibrosis score 0–1), subgroup IIb (n=38; fibrosis score 2–3) and subgroup IIc (n=22; fibrosis score 4–6). DNA was multiplied by polymerase chain reaction (PCR). ACE genotype frequency in HCV infected patients was significantly different comparing to controls (X2=7.169, P=0.028). With non-significant difference in ACE D/I genotypes and allele frequencies among the patient subgroups (P>0.05),the frequency of the DD, DI and II genotypes in subgroup IIa, subgroup IIb and subgroup IIc were (53.3%, 36.6%, 10%), (44.7%, 44.7%, 10.5%) and (50%, 22.7%, 27%), respectively. The D and I allele frequency were (71.66%, 28.33%), (67.1%, 32.9%) and (61.36%, 38.63%), respectively. ACE serum levels were significantly increased in DD more than DI and II (t=2.56, 3.43, P<0.05), respectively, with non-significant association in sonographic findings, viral load and liver function test (LFT) parameters with the ACE genotypes. Serum ACE levels were significantly increased in all patient subgroups when compared to controls with a non significant difference of ACE levels between subgroup IIb and IIc. We concluded that the D/D genotype is associated with HCV infection but not associated with degree or the progression of hepatic fibrosis.

ChemInform Abstract: diaza‐Wittig Reactions of Diketoesters Phosphazines: Synthesis of Tetrasubstituted Fluoroalkyl‐Containing Pyridazines.

Pyridazines attract much attention due to their biological activity [1], some of them are used in the treatment of Parkinson, Alzheimer, and other neurodegenerative diseases [2, 3]. Therefore the development of new methods of preparation of this class compounds is an urgent problem of the synthetic organic chemistry. In keeping with published reports 3,4,6-trisubstituted pyridazines can be synthesized in good yields from 2-vinyl derivatives of 2-diazoketones by the intramolecular diaza-Wittig reaction [4–9]. The only example of the synthesis of the tetrasubstituted pyridazine with the use of analogous procedure was described in [10], where by the diaza-Wittig reaction of the posphazine of 4-diazopyrrolidinetrione with ethyl acetoacetate bicyclic pyrrolo[3,4-c]pyridazine was obtained. The aim of our study was the elucidation of the possibility to obtain 3,4,5,6-tetrasubstituted pyridazines by the intermolecular diaza-Wittig reaction of phosphazines of acyclic diazoketoesters with 1,3-diketones and ketoesters . We used as diazo substrates methyl and ethyl 2-diazo-3-oxo-4,4,4-trifl uorobutanoates (Iа, Ib), аnd as 1,3-dicarbonyl compounds ketoesters IIa, IIb and diketones IIc, IId. In the preparation of the phosphazines from diazoketoesters I we applied the triphenylphosphine (IIIа) commonly used in the Staudinger reaction [11–13] and more nucleophilic [14] tris(dimethylamino)phosphine (IIIb). The reaction of diazoketoesters Iа, Ib with ketoester IIа was carried out similarly to procedure [10] using PPh3. It presumably proceeded with the intermediate formation of triphenylphosphazines IVа, IVb and was of low effi ciency. The monitoring of the reaction progress by 1Н NMR spectroscopy showed that under these conditions a fairly complex mixture of products formed containing alongside the target compounds also a diazoacetic ester phosphazine and the other reaction products, and according to the data of 1Н NMR spectrum of the reaction mixture the yield of pyridazines V did not exceed 30–32%.

Reactions of phosphorus trihalides with 6-(adamantan-1-yl)imidazo[2,1-b]thiazoles

We found that 6-(adamantan-1-yl)imidazothiazoles Ia–Ic do not react with phosphorus trichloride under similar conditions. (Adamantan-1-yl)imidazothiazole Ia reacts with phosphorus tribromide to yield the compound IIa, whereas the reactions of adamantlyimidazothiazoles Ib and Ic give rise to the dibromoderivatives IIIa and IIIb. Compounds Ia–Ic give the analogous products at reflux in liquid bromine. Compounds IIa–IIc were formed under milder conditions [3] in the reaction of equimolar amounts of the studied thiazoles with bromine in chloroform. zolium bromide IVa. Yield 93%, mp 128–130°C. H NMR spectrum, δ, ppm: 1.73 s (6H, 4',6',10'-CH2), 1.87 s (6H, 2',8',9'-CH2), 2.01 s (3H, 3',5',7'-CH), 2.34 s (3H, Me), 6.74 s (1H, 5-H), 7.37 s (1H, 3-H). Found N, %: 10.20. C16H20N2S. Calculated N, %: 10.28.

Diaza-Wittig reactions of diketoesters phosphazines: Synthesis of tetrasubstituted fluoroalkyl-containing pyridazines

Pyridazines attract much attention due to their biological activity [1], some of them are used in the treatment of Parkinson, Alzheimer, and other neurodegenerative diseases [2, 3]. Therefore the development of new methods of preparation of this class compounds is an urgent problem of the synthetic organic chemistry. In keeping with published reports 3,4,6-trisubstituted pyridazines can be synthesized in good yields from 2-vinyl derivatives of 2-diazoketones by the intramolecular diaza-Wittig reaction [4–9]. The only example of the synthesis of the tetrasubstituted pyridazine with the use of analogous procedure was described in [10], where by the diaza-Wittig reaction of the posphazine of 4-diazopyrrolidinetrione with ethyl acetoacetate bicyclic pyrrolo[3,4-c]pyridazine was obtained. The aim of our study was the elucidation of the possibility to obtain 3,4,5,6-tetrasubstituted pyridazines by the intermolecular diaza-Wittig reaction of phosphazines of acyclic diazoketoesters with 1,3-diketones and ketoesters . We used as diazo substrates methyl and ethyl 2-diazo-3-oxo-4,4,4-trifl uorobutanoates (Iа, Ib), аnd as 1,3-dicarbonyl compounds ketoesters IIa, IIb and diketones IIc, IId. In the preparation of the phosphazines from diazoketoesters I we applied the triphenylphosphine (IIIа) commonly used in the Staudinger reaction [11–13] and more nucleophilic [14] tris(dimethylamino)phosphine (IIIb). The reaction of diazoketoesters Iа, Ib with ketoester IIа was carried out similarly to procedure [10] using PPh3. It presumably proceeded with the intermediate formation of triphenylphosphazines IVа, IVb and was of low effi ciency. The monitoring of the reaction progress by 1Н NMR spectroscopy showed that under these conditions a fairly complex mixture of products formed containing alongside the target compounds also a diazoacetic ester phosphazine and the other reaction products, and according to the data of 1Н NMR spectrum of the reaction mixture the yield of pyridazines V did not exceed 30–32%.

A risk-adapted strategy of radiotherapy or cisplatin-based chemotherapy in stage II seminoma

ObjectivesIndications for radiotherapy and chemotherapy in stage II seminoma are currently debated. Materials and methodsSince1980, the policy at Institut Gustave Roussy was to treat patients with stage IIA-B disease with external radiotherapy and patients with stage IIB-C with cisplatin-based chemotherapy. In stage IIB disease, 3 cm was the usual tumor size threshold above which individual patients were considered for chemotherapy. ResultsDuring the period 1980–2001, 67 patients with stage II seminoma were treated: stage IIA (n = 5), stage IIB (n = 31), and stage IIC (n = 31). The median age was 40 years (range: 23–64). Among 37 patients who received radiotherapy, 5, 28, and 4 had a stage IIA, IIB, and IIC, respectively. Among 30 patients who received chemotherapy, 27 had a stage IIC. With a median follow-up of 9.4 years, 19 relapses (28%) occurred, including 11 and 8 cases treated with radiotherapy (30%) and chemotherapy (27%), respectively. The 5-year relapse-free survival was 71% (95% CI: 59–80). All but three relapses were salvaged with chemotherapy followed in selected cases by surgical resection of residual masses. Only 3 patients died of seminoma. The 5-year overall survival rate is 97% (95% CI: 89–99). Five patients subsequently developed a non-germ-cell second cancer, which occurred within the radiation field in 3 cases. ConclusionWith an overall survival rate of 97%, the overall outcome of patients with stage II seminoma managed according to this risk-adapted strategy is good. The possibility of extending the indications for chemotherapy to selected stage IIB seminoma patients needs to be further evaluated as potentially beneficial in terms of relapse risk.

Synthesis of a New Series of 2-(2-Hydroxynaphthylazo)aryltellurium Compounds

A new series of 2-(2-hydroxynaphthylazo)arylmercury chlorides (Ia–Ib) were prepared by azo coupling of diazonium salts of 2-aminophenyl-, 2-amino-5-bromophenyl-, 2-amino-5-methylphenyl-, and 2-amino-5-nitrophenylmercury chlorides with 2-naphthol. Reactions of compounds Ia–Ib with tellurium tetrabromide in 1:1 and 2:1 molar ratios in dry dioxane gave 2-(2-hydroxynaphthylazo)aryltellurium tribromides (IIa–IId) and bis(2-(2-hydroxynaphthylazo)aryl)tellurium dibromides (IIIa–IIId), respectively, in good yields. Reduction of compounds IIa–IIc and IIIc–IIId by ethanolic hydrazine hydrate gave the corresponding ditellurides (IVa–IVc) and tellurides (Vc–Vd), respectively, in moderate to good yields. Treatment of compounds IIIb and IIId with [Pd(PPh3)4] in acetonitrile gave new symmetrical biaryls containing azo groups. All compounds were characterized by spectroscopic data and elemental analysis. GRAPHICAL ABSTRACT

One-step transformation of tetracyanocyclopropyl ketones into pyrrolo[3,4-c]pyridine derivatives

Tetracyanocyclopropyl ketones obtainable via modified Wideqvist reaction are accessible and convenient precursors of a number of heterocyclic systems [1–3]. Reactions of cyclopropyl ketones Ia–Ic with alkoxides give rise to 2-[2-alkoxy-5-amino-4-cyano-2-phenylfuran-3(2H)-ylidene]malononitriles [3]. We anticipated that replacement of the ketone acetal fragment in the latter by more labile semiacetal moiety should facilitate recyclization of the furan ring into pyrrole. Such transformation could be promoted using hydroxide ion instead of alkoxide in reactions with cyclopropyl ketones Ia–Ic. The above assumption was verified by studying the reaction of cyclopropyl ketones Ia–Ic with aqueous sodium hydroxide. We found that this reaction involves not only expected recyclization of furan ring into pyrrole but also annelation of pyridine ring. The structure of compounds IIa–IIc isolated by neutralization of the reaction mixture with a solution of sulfuric acid was confirmed by the H NMR and mass spectra. The H NMR spectra contained singlets at δ 7.12– 7.69 and 8.78–9.02 ppm, which were assigned to the hydroxy and NH protons, respectively, in the pyrrole ring. The NH proton in the pyridine ring resonated as

Reactions of bicyclo[4,1,0]heptane derivatives with phosphorus pentachloride

Bicycloalkanes containing three-membered cycle possess the enhanced activity to electrophile reagents action due to raised angular and torsion strains. In this connection the study of reactions of phosphorus pentachloride with bicyclo[4,1,0]heptane derivatives are of significant interest. We pioneered in using as a latter the easily available norcarane, 7,7-dichloroand 2-alkoxy-7,7-dichloronorcaranes Ia–Ic. Under standard conditions [1], norcarane was found to phosphorylation with a small ring cleavage to form cyclohexylidenemethyland 1-chlorocyclohexylmethylphosphonic dichlorides. 7,7-Dichloronorcarane does not react with phosphorus pentachloride under similar conditions that is probably caused by the increased small ring stability. 2-Alkoxy-7,7-dichloronorcaranes Ia–Ic are phosphorylated on alkoxyl group to give 2-(7,7dichlorobicyclo[4,1,0]heptyl-2-oxy)ethenylphosphonic dichlorides IIa–IIc. Theoretically possible reaction pathway at the cycle is not observed that is proved by the absence of product with P–C bond when one carried out reaction with 2-methoxy-7,7-dichloronorcarane. This reaction gives rise only to 3-dichloromethylenecyclohexanone, the product of competitive reaction occurring at the three-membered cycle. The possible scheme of the formation of latter was described by us earlier [2]. DOI: 10.1134/S1070363210050336

Synthesis of a new organic anion by reaction of 4-aryl(hetaryl)-4-oxobutane-1,1,2,2-tetracarbonitriles with ammonia

4-Oxoalkane-1,1,2,2-tetracarbonitriles are known to react with concentrated aqueous ammonia to produce compounds of two types. Adducts of tetracyanoethylene and cyclic ketones (such as cyclopentanone and cyclohexanone) give rise to 2,7-diazabicyclic compounds [1], whereas from aliphatic tetracyanoethylated ketones isonicotinic acid derivatives are formed [2]. There are no published data on reactions of aqueous ammonia with tetracyanoalkanones derived from methyl aryl(hetaryl) ketones. When such reactions were carried out under the conditions reported in [1, 2], strong tarring occurred, and no individual products were isolated. By varying the conditions of this reaction we succeeded in obtaining ammonium 4-aryl1,1,2,2-tetracyano-4-oxobutan-1-ides IIa–IIc by mixing ketones Ia–Ic with a freshly prepared solution of ammonia in ethyl acetate at reduced temperature. Structures analogous to IIa–IIc but having singly charged metal cations were reported in [3, 4]. Compounds IIa–IIc turned out to be unstable in the solid state: on exposure to air they lost hydrogen cyanide with formation of ammonium 4-aryl-1,1,2-tricyano-4oxobut-2-en-1-ides IIIa–IIIc that are derivatives of a new organic anion. Intermediate formation of ammonium salts IIa–IIc is confirmed by their transformation into initial ketones Ia–Ic by the action of dilute hydrochloric acid immediately after isolation. Some structural similarity of salts IIIa–IIIc to betaines described in [5] may be noted. The latter were synthesized from tetracyanoethylene and pyridinium ylides. The structure of compounds IIIa–IIIc was confirmed by their IR, H NMR, and mass spectra and elemental analyses. The synthesis of salts III is an example of new reaction pathway of 4-oxoalkane1,1,2,2-tetracarbonitriles with ammonia. Ammonium 1,1,2-tricyano-4-(4-methoxyphenyl)4-oxobut-2-en-1-ide (IIIa). 4-(4-Methoxyphenyl)-4oxobutane-1,1,2,2-tetracarbonitrile (Ia), 0.139 g (0.5 mmol), was added to 2 ml of a freshly prepared solution of ammonia in ethyl acetate, cooled to –10°C, and the mixture was vigorously stirred until it became homogeneous. After several minutes, a solid separated and was filtered off, washed with cold ethyl acetate, and kept for 5–7 days on exposure to air. Yield 0.115 g (86%), mp 84–85°C. IR spectrum, ν, cm: 2230, 2199 (C≡N); 1667 (C=O). H NMR spectrum, δ, ppm: 3.81 s (3H, OCH3), 6.51 s (1H, CH), 7.01 d (2H, Harom), 7.07 br.s (4H, NH4), 7.79 d (2H, Harom). Mass spectrum: m/z 251 (Irel 49%) [M – NH3]. Found, %: C 62.51; H 4.77; N 20.95. C14H12N4O2. Calculated, %: C 62.68; H 4.51; N 20.88. Compounds IIIb and IIIc were synthesized in a similar way. Ammonium 1,1,2-tricyano-4-oxo-4-(2-thienyl)but-2-en-1-ide (IIIb). Yield 0.096 g (79%), mp 85– 87°C. IR spectrum, ν, cm: 2221, 2196 (C≡N); 1672 (C=O). H NMR spectrum, δ, ppm: 6.41 s (1H, CH), 7.16 d.d (1H, Harom), 7.19 br.s (4H, NH4), 7.65 d.d (1H, R = 4-MeOC6H4 (a), 2-thienyl (b), 3,4-(MeO)2C6H3 (c). ISSN 1070-4280, Russian Journal of Organic Chemistry, 2010, Vol. 46, No. 4, pp. 597–598. © Pleiades Publishing, Ltd., 2010. Original Russian Text © M.Yu. Belikov, O.V. Ershov, A.V. Eremkin, Ya.S. Kayukov, O.E. Nasakin, 2010, published in Zhurnal Organicheskoi Khimii, 2010, Vol. 46, No. 4, pp. 604–605.