No abstract

Diamondoid molecules are cage-like, ultra stable and saturated hydrocarbons. The basic repetitive unit of the diamondoids is a ten-carbon tetracyclic cage system called "adamantane" (Fig. 1.1). They are called "diamondoid" because they have at least one adamantane unit and their carbon-carbon framework is completely or largely superimposable on the diamond lattice (Balaban and Schleyer, 1978; Mansoori, 2007). The diamond lattices structure was first determined in 1913 by Bragg and Bragg using X-ray diffraction analysis (Bragg and Brag, 1913). Diamondoids show unique properties due to their exceptional atomic arrangements. Adamantane consists of cyclohexane rings in "chair" conformation. The name adamantane is derived from the Greek language word for diamond since its chemical structure is like the three-dimensional diamond subunit as it is shown in Fig. 1.2. 1.2. Classification and Crystalline Structure of Diamondoids The first and simplest member of the diamondoids group, adamantane, is a tricyclic saturated hydrocarbon (tricyclo[3.3.1.1(3.7)]decane, according to the von Bayer systematic nomenclature).

O‐Acylamidoxime and 1,2,4‐oxadiazole derivatives were synthesized from adamantanecarbonyl chloride 1 and a diversity of arylamidoximes 2 a‐k. First, O‐acylamidoximes intermediates 3 a‐k were synthesized and subsequent cyclization under microwave irradiation afforded 1,2,4‐oxadiazol derivatives 4 a‐k. Molar Heat of Reaction Calorimetry studies performed from O‐acylamidoximes revealed influence of the substituent groups. A one‐pot two‐step methodology was also developed proving to be a viable protocol. Compounds were characterized by 1H and 13C Nuclear Magnetic Resonance (NMR) Spectroscopy, Elemental Analysis or High Resolution Mass Spectral Analysis, and subjected to cytotoxic studies in non‐tumoral Vero cells and antiproliferative activity tests in six malignant cell lines. Our findings suggest that compounds 3 derivatives presented a concentration‐dependent profile for chronic myeloid leukemia (K562) and acute promyelocytic leukemia (HL‐60) cell.

In this review paper, we report the molecular structure, origin, natural occurrence and variety of diamondoid hydrocarbons in petroleum fluids and other fossil fuels. In addition, we present the role of diamondoids as geochemical tools for petroleum characterisation, ways diamondoid molecules are used to play an important role in petroleum evaluation, and may be used to assess origin, extend of biodegradation and thermal maturity, as well as to identify the occurrence of petroleum. The diamondoid-based diagnostic ratios in environment science as well as diamondoid-based diagnostic ratios for petroleum maturity parameters are also presented and discussed. Such diamondoid-based parameters may be used to assess oil source, maturity and biodegradability, providing supporting information, especially when traditional evaluation data are not available or are difficult to interpret. We also report applications and problems associated with diamondoids in petroleum exploration and production. That is the role of diamondoids in petroleum and natural gas production fouling as well as separation, detection and measurements of petroleum diamondoids. We realise that the presence of diamondoids in petroleum has become much more than a chemical curiosity since it has advanced to be a resourceful instrument in petroleum science, biomedicine, materials science and an important family of molecular building blocks in nanotechnology. [

The diagnosis of lung cancer mostly occurs when the cancer is already in an advanced stage. In this situation, there are few options for the treatment and most of them have few chances of success. In this study, we developed and tested etoposide microparticles as a diagnostic agent for imaging lung cancer at early stages of development. We tested etoposide microparticles labeled with technetium 99m in inducted mice. The results demonstrated that over 10% of the total dose used was uptake by the tumor site. Also, the results showed that the microparticles had a good renal clearance and low uptake by liver and spleen. The data suggest that these micro-radiopharmaceuticals may be used for lung cancer imaging exam, especially single-photo emission computed tomography (SPECT).[Formula: see text].