On triazoles XIX: The reaction of 5-amino-1,2,4-triazoles with functionalized acetoacetic esters

Summary Different functionalized alkyl 3-oxo-butyrates (2) were reacted with 5-amino-3-Q-1H-1,2,4-triazoles (1) to yield3 and4 type 1,2,4-triazolo[1,5-a]pyrimidinones. In case of2 (R ¹=methyl,R ²=1-ethoxycarbonylethyl,R ³=ethyl) beside the corresponding derivative4 the unexpected 5,6-dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-methylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-one (7) was isolated, representing a novel ring system.

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Über Triazole, 19. Mitt.: Die Reaktion von 5-Amino-1,2,4-triazolen mit funktionalisierten Acetoessigestern

Zusammenfassung Verschiedene funktionalisierte 3-Oxo-buttersäurealkylester (2) wurden mit 5-Amino-3-Q-1H-1,2,4-triazolen (1) umgesetzt, wobei 1,2,4-Triazolo[1,5-a]pyrimidinone der Typen3 und4 erhalten wurden. Im Fall von2 (R ¹=Methyl,R ²=1-Ethoxycarbonylethyl,R ³=Ethyl) wurde neben dem erwarteten Derivat4 das unerwartete 5,6-Dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-me-thylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-on (7) isoliert, welches ein neues Ringsystem darstellt.

     

Generalizations and error analysis of the iterative operator splitting method

The properties of iterative splitting with two bounded linear operators have been analyzed by Faragó et al. For more than two operators, iterative splitting can be defined in many different ways. A large class of the possible extensions to this case is presented in this paper and the order of accuracy of these methods are examined. A separate section is devoted to the discussion of two of these methods to illustrate how this class of possible methods can be classified with respect to the order of accuracy.     

An α-Lactam as an Alkilating Agent

The ‘normal’ reaction of α-lactams (aziridinones) is mcleophilic ring ening,¹ which can occur with fission of either one of the three bonds (a-b-c), depending on the reagent, to yield and acyclic addition prodnct (I,II,III).²     

Artificial intelligence in electrostatic risk management

In the last two decades protection against electrostatic hazards became a very important topic. The increase in the range of possible faults fast automated systems and complex fault analysis is required.The tools of artificial intelligence and expert systems have been applied successfully on this field and this paper aims to take a step further. While giving some insight to the currently used tools, another AI method, the 'support vector machines' are introduced in this paper. Besides a brief review on SVMs they are introduced to the SCOUT system, a novel approach to electrostatic hazard management.     

Efficient syntheses of zoledronic acid as an active ingredient of a drug against osteoporosis

The reaction of 1H-imidazol-1-ylacetic acid and two equivalents of phosphorus trichloride/phosphorous acid at 75?°C in sulfolane, or in the presence of catalytic amounts of [bmim][BF₄] afforded zoledronic acid in yields up to 75%. The joint use of the ionic liquid additive and sulfolane as the solvent was synergetic affording highly valuable zoledronic acid in a record yield of 93%.     

Calculating all elements of minimal index in the infinite parametric family of simplest quartic fields

It is a classical problem in algebraic number theory to decide if a number field is monogeneous, that is if it admits power integral bases. It is especially interesting to consider this question in an infinite parametric familiy of number fields. In this paper we consider the infinite parametric family of simplest quartic fields K generated by a root ξ of the polynomial P _t (x) = x ⁴ ? tx ³ ? 6x ² +tx+1, assuming that t > 0, t ≠ 3 and t ² +16 has no odd square factors. In addition to generators of power integral bases we also calculate the minimal index and all elements of minimal index in all fields in this family.     

E. Thomas Strom and Seth C. Rasmussen,Eds, 100+ Years of Plastics. Leo Baekeland and Beyond. ACS Symposium Series Volume 1080

Structural Chemistry -     

Polymerization-Driven Photoluminescence in Alkanolamine-Based C-Dots

Carbonized polymer dots (CPDs), a peculiar type of carbon dots, show extremely high quantum yields, making them very attractive nanostructures for application in optics and biophotonics. The origin of the strong photoluminescence of CPDs resides in a complicated interplay of several radiative mechanisms. To understand the correlation between CPD processing and properties, the early stage formation of carbonized polymer dots has been studied. In the synthesis, citric acid monohydrate and 2-amino-2-(hydroxymethyl)propane-1,3-diol have been thermally degraded at 180 °C. The use of an oil bath instead of a more traditional hydrothermal reactor has allowed the CPD properties to be monitored at different reactions times. Transmission electron microscopy, time-resolved photoluminescence, nuclear magnetic resonance, infrared, and Raman spectroscopy have revealed the formation of polymeric species with amide and ester bonds. Quantum chemistry calculations have been employed to investigate the origin of CPD electronic transitions. At short reaction times, amorphous C-dots with 80 % quantum yield, have been obtained.