Fused pyrimidine derivativesFused pyrimidine derivatives R 0515 Simple One-Pot Three-Component Synthesis of 2-Oxo-1,11b-dihydro-2H-pyrimido[2,1-a]isoquinolines. -(ADIB*, M.; MOLLAHOSSEINI, M.; YAVARI, H.; SAYAHI, M. H.; BIJANZADEH, H. R.; Synthesis 2004, 6, 861-864; Dep. Chem., Fac. Sci., Tehran Univ., Tehran, Iran; Eng.) -C. Herrmann

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O n e -P o t S y n t h e s i s o f 2 -O x o -1 , 1 1 b -d i h y d r o -2 H -p y r i m i d o [ 2 , 1 -a ] i s o q u i n o l i n e sAbstract: Isoquinoline reacts smoothly with dialkyl acetylenedicarboxylates in the presence of isocyanates to produce dialkyl 2-oxo-1,11b-dihydro-2H-pyrimido[2,1-a]isoquinoline-3,4-dicarboxylates in good yields.The development of simple synthetic routes for widely used organic compounds from readily available reagents is one of the major tasks in organic synthesis. 1 Bridgehead nitrogen heterocycles are of interest because they constitute an important class of natural and unnatural products, many of which exhibit useful biological activity. 2,3 The interest in fused bicyclic 6-6 systems with one ring junction and one extra nitrogen atom, stems from the appearance of saturated and partially saturated pyrido[1,2-a]pyrimidine ring systems and their 8,9-benzo analogues (pyrimido[2,1-a]isoquinolines) in many biologically active compounds and natural products, 3-10 some of which are key intermediates for the synthesis of rutaecarpine alkaloids, some have characteristic pharmacological properties such as analgesic, antiallergic, antiasthmatic, and antipsychotic agents, and some are neutral hydrogen chloride acceptors in organic synthesis. 3 As part of our current studies on the development of new routes in heterocyclic synthesis, 11 in this paper, we wish to report a simple synthesis of functionalized pyrimido[2,1-a]isoquinolines.The reaction of isoquinoline (1) and dialkyl acetylenedicarboxylates (2) in the presence of isocyanates (3) proceeds smoothly in dichloromethane at ambient temperature to produce dialkyl 2-oxo-1,11b-dihydro-2H-pyrimido[2,1-a]isoquinoline-3,4-dicarboxylates (4) in 75-99% yields (Scheme 1).The reactions were carried out by first mixing isoquinoline and the isocyanate and then the acetylenic ester was added slowly, proceeding spontaneously in CH 2 Cl 2 , and were complete within an hour (see experimental).The structures of compounds 4a-g were deduced from their elemental analyses and their IR, 1 H NMR and 13 C NMR spectra. The mass spectrum of 4a displayed the molecular ion (M + ) peak at m/z = 390, which is consistent with the 1:1:1 adduct of isoquinoline, dimethyl acetylenedicarboxylate (DMAD) and phenyl isocyanate. The 1 H NMR spectrum of 4a exhibited three singlets readily recognized as arising from two methoxy (d = 3.87 and 3.98) and the methine (d = 6.55) protons, an AB quartet system for two vinylic protons of the enamine moiety of isoquinoline ring (d = 6.01 and 6.56, J = 7.8 Hz), and the characteristic multiplets for the aromatic protons (d = 6.6-7.2). Scheme 1Downloaded by: University of British Columbia. Copyrighted material.

Efficient One-pot Three-component Synthesis of 7-Oxo-1,7,8,8a-tetrahydroimidazo[1,2-a]pyrimidines S y n t h e s i s o f 7 -O x o -1 , 7 , 8 , 8 a -t e t r a h y d r o i m i d a z o [ 1 , 2 -a ] p y r i m i d i n e sAbstract: 1-Methyl imidazole reacts smoothly with dialkyl acetylenedicarboxylates in the presence of isocyanates to produce dialkyl 1-methyl-7-oxo-1,7,8,8a-tetrahydroimidazo[1,2-a]pyrimidine-5,6-dicarboxylates in excellent yields.

Abstract. In this paper, Radial Basis Function (RBF) Neural Network and Logistic Regression (LR) models were proposed for hazard prediction of landslides in a part of the Semirom area (Iran) to compare their accuracy and performance. For this purpose, a spatial database of the study area was prepared that consists of 68 landslide locations and 11 influencing information layers including slope, aspect, profile curvature, plan curvature, distance from faults, distance from roads, distance from residential regions, distance from rivers, land use, lithology and rainfall. Landslide hazard maps were prepared for the study area by applying the proposed algorithms. Performance of the models was assessed using the Receiver Operating Characteristic (ROC) curve and area under the ROC curve (AUC). The coefficient of determination (R2), the root mean square error (RMSE), and the Normal Root Mean Square Error (NRMSE) were calculated for proposed methods. The outcomes showed that the RBF Neural Network has the highest R2 (0.8224), in comparison to that of the LR model (0.5365). Also, the ROC plots, RMSEs and NRMSEs showed that the proposed RBF Neural Network is much better than the LR model. Consequently, it can be concluded that the RBF Neural Network is the best regression model in this study and it can be considered as a capable method for landslide hazard mapping in landslide-susceptible areas.

The 1,2,4-benzotriazine nucleus fused to a benzene ring is a prominent heterocyclic substructure present in numerous pharmacologically active compounds. To date, many 1,2,4-benzotriazine analogues possessing a wide spectrum of potent pharmacological activities are known. This review compiles information on the synthesis, chemical reactions, medicinal chemistry aspects and applications of 1,2,4-benzotriazines.

Fused pyrimidine derivativesFused pyrimidine derivatives R 0515 Efficient One-Pot Three-Component Synthesis of 7-Oxo-1,7,8,8a-tetrahydroimidazo[1,2-a]pyrimidines. -Addition of diesters (III) to a solution of isocyanates and N-methylimidazole gives the title compounds (IV) in good yields. -(ADIB*, M.; MOLLAHOSSEINI, M.; YAVARI, H.; SAYAHI, M. H.; BIJANZADEH, H. R.; Synlett 2004, 6, 1086-1088; Dep. Chem., Univ. Tehran, Tehran, Iran; Eng.) -Mais 38-163

Fused pyrimidine derivativesFused pyrimidine derivatives R 0515 Efficient One-Pot Synthesis of 2-Oxo-1,9a-dihydro-2H-pyrido[1,2-a]pyrimidine Derivatives. -Slow addition of acetylenic esters (III) to a mixture of pyridines (I) and isocyanates (II) causes spontaneous reaction between the three components to afford the title derivatives (IV) in excellent yields. The reaction is performed under neutral conditions without any activation or modification. The simplicity of this one-pot method is an interesting alternative to other procedures. -(ADIB*, M.; YAVARI, H.; MOLLAHOSSEINI, M.; Tetrahedron Lett. 45 (2004) 8, 1803-1805; Dep. Chem., Fac. Sci., Tehran Univ., Tehran, Iran; Eng.) -H. Hoennerscheid 23-174