One-pot, mild and efficient multicomponent synthesis of novel various spiro-nitrogen heterocycle compounds

ABSTRACT. One-pot, mild and efficient synthesis of various spiro-nitrogen heterocycle compounds, based on the reaction of ninhydrin and 1,2-diamino-benzene, (indenoquinoxalin), with N-heterocycle compounds and dialkylacetylenedicarboxylates is described. Using this approach, various spiro-nitrogen heterocycle compounds at a temperature of 50-60 °C in acetonitrile solvent, can be obtained very high yields.   KEY WORDS: Ninhydrin, 1,2-Diaminobenzene, spiro-Nitrogen heterocycle compounds, Indenoquinoxalin, N-heterocycle compounds, Dialkylacetylenedicarboxylates   Bull. Chem. Soc. Ethiop. 2023, 37(1), 115-122.                                                           DOI:https://dx.doi.org/10.4314/bcse.v37i1.10&nbsp

Nitrogen-15 nuclear magnetic resonance spectroscopy. Carbodiimides

High-resolution, 18.25-MHz nitrogen-15 NMR spectra of several carbodiimides (1) have been obtained at the natural-abundance level. The high-field positions of the ^(15)N resonances of these substances are discussed in terms of two different shielding mechanisms. Solvent influences on the ^(15)N and ^(13)C chemical shifts of carbodiimides are small. Both the ^(13)C and ^(15)N spectra of l-ethyl-3-[3-(dimethylamino)propyl]carbodiimidhey drochloride indicate that at least four different structural isomers are present in dimethyl sulfoxide solution at room temperature. Information about the dimerization of carbodiimides in the presence of alkylating agents has been obtained from ^(15)N and ^(13)C NMR

Diastereoselective Synthesis and Conformation of trans-2;3-Dibenzoyl-1;4-dithiacyclohepta

The reaction of dibenzoylacetylene and propane-1,3-dithiol in the presence of triphenylphosphine leads to diastereoselective synthesis of the mesocyclic dithioether trans-2,3-dibenzoyl- 1,4-dithiacycloheptane in 70 % yield. The results of ab initio calculations at HF/6-31G* level show that the trans isomer is 31.3 kJ mol–1 more stable than the cis geometry

A three-component synthesis of functionalized ketenimines by the reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates in the presence of 2-quinolinol

The 1:1 reactive intermediates generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates were trapped by 2-quinolinol to yield highly functionalized ketenimines and, in some cases, minor amounts of 1-azabuta-1,3-dienes

Epidemiological study on some environmental and management parameters affecting on WSD occurrence in Fenneropenaeus indicus and Penaeus vannamei

For the first time white spot disease (WSD) was reported in shrimp farms of khoozestan province, in southwest of IRAN in 2002. Then in 2005 the neighbor province, boushehr, was contaminated. In 2008 WSD outbreak reported in sistan-bloochestan province in southeast of Iran. In 2015 all of southern shrimp farms of country except Hormozgan, the middle southern province, which has remained free of WSD, are being contaminated. White Spot disease suspended shrimp culture in thousands hectares of shrimp farms. Considering that white spot disease has not been observed in Hormozgan province yet, the question is; to what extent environmental and management factors participated in preventing WSD outbreak or cause WSD outbreak. In this study (20102012), the effects of environmental factors and management, stressors that decrease immune system function of shrimp are discussed. In addition, the role of pathogen as the main factor of outbreak is discussed. The goal of this study is to define environmental parameters and management practices associates with outbreak of white spot disease in affected provinces and discover reasons of being Hormozgan province free of this disease. In this study the role of the local environmental factors and management practice stressors in susceptibility to WSD was determine. Both the effects of environmental factors in water of ponds including total ammonia, nitrogen, dissolved oxygen, pH, salinity, transparency, and temperature and management issues related to biosecurity are studied. There were overlaps on physical and chemical parameter values obtained in clear areas with contaminated areas .Results of the data analysis suggest that lack of association with WSD incidence was 7 times greater than WSD incidence despite of disease outbreak in sistan-bloochestan province, so other sources of white spot disease virus incidence was suspected in affected areas. Histopathological examinations and polymerase chain reaction (PCR) tests during project performance did not reveal white spot disease virus evidences in post larvae examined from khoozestan province stocked in farms but disease outbreak was happened in that farms , so we suspected to management practice include feed , pond preparation and carrier of disease. Recorded values of temperature and salinity in some months during inspection in Hormozgan province specified stressful condition that may lead to WSD outbreak, however the disease did not appear. Therefore the hypothesis that the water physical and chemical conditions are reasons to prevent disease outbreak in Hormozgan province is being rejected. The policy of Hormozgan’s fishery authorities, to replaced Fenneropenaeus indicus with specific pathogen free Litopenaeus vannamei, that is more resistant to some of diseases, before incidence of WSD in farms and to before being endemic in the Hormozgan province, made an advantage compare to affected southern provinces that introduced Litopenaeus vannamei after WSD prevalence to their farms. However it does not guarantee to maintain current trend of being Hormozgan province farms free of white spot disease. Therefore establishing the principals of biosecurity are strongly emphasized. Strategies taken by the proficient authorities in preparation of SPF shrimp broodstock can be the most important factor in preventing WSD. Regarding biosecurity principals purchased feed must be free of shrimp head powder. Construction the new shrimp farms should be as far as it could be away from contaminated areas

^(15)N Nuclear Magnetic Resonance Spectroscopic Investigation of Differential Rates of Base-Catalyzed N-H Proton-Exchange Reactions of 1-aza-2-Cycloheptanone and 1-aza-2-Cycloheptanethione

Natural-abundance proton-coupled ^(15)N NMR spectra of an equimolar solution of the title compounds in dimethyl sulfoxide, to which was added aqueous sodium hydroxide, show that N-H proton exchange of the thiolactam is about 1500 times faster than that of the lactam at 25°C. This rate difference is suggested to arise from a greater contribution of the polar resonance structure for the thiolactam